The Garden Shed

A Community Newsletter published by the Piedmont Master Gardeners

December 2017 - Vol. 3 No. 12

 

Olive Cheese Puffs

Magical Repelling Powers of Marigolds — Myth or Fact?

The Pros and Cons of the Eastern Redcedar

For comments, questions or suggested topics for future Garden Shed articles contact us at: garden-shed@piedmontmastergardeners.org.

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Table of Contents

Recipe of the Month

Olive Cheese Puffs

By Cate Whittington

Wow your holiday guests with this tasty make-ahead appetizer!

Tasks and Tips

The Vegetable Garden in December

By Cleve Campbell

Happy holidays from The Garden Shed!  You’ve completed all your Christmas shopping and done all your decorating, so now you're looking for a few gardening tasks. Right?  Well, here's our list of December tasks and tips for the edible garden:...

In the Edible Garden

Magical Repelling Powers of Marigolds — Myth or Fact?

By Cleve Campbell

"What are you doing?"

Tasks and Tips

The Ornamental Garden in December

By Pat Chadwick

December is a good time to reflect on your garden's successes and failures.

In the Ornamental Garden

The Pros and Cons of the Eastern Redcedar

By Pat Chadwick

The eastern redcedar -- is it a "weed" or a valuable native tree?

Feature

Reflections on the Winter Landscape

By Pat Chadwick

Winter, the dormant season, is when the bare bones of the landscape are revealed.

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The Pros and Cons of the Eastern Redcedar

When is a cedar not a cedar? When it’s an eastern redcedar. The name is a misnomer. This plant is actually a juniper, as its botanical name (Juniperus virginiana) indicates. True cedars belong to the Cedrus genus and are not native to this country. Sources are inconsistent on the treatment of the common name, variously referring to it as eastern red cedar (two words), eastern redcedar (one word), eastern red-cedar (hyphenated), and red cedar, among many other names.

Juniperus virginiana (eastern redcedar tree)

To say this plant has an image problem is an understatement. It has been snubbed over the years by tree aficionados, partially because it is so common. This ubiquitous native evergreen is the most widely distributed conifer in the eastern part of North America. It grows prolifically along fencerows, highways, and back roads, as well as in pastures and open fields that are not routinely mowed or maintained. The seedlings can rapidly take over a piece of land, making this tree equivalent to a “first responder” in populating abandoned properties and neglected fields. It would not be unreasonable to regard this plant as weedy and even invasive in poorly managed sites. In fact, it has been documented as a threat to prairie and scrubland ecosystems in states such as Oklahoma and Kansas.

Another problem with the eastern redcedar is its role as an alternate host for cedar-apple rust, a Gymnosporangium pathogen that is destructive to pome fruit trees such as apple, pear, and quince.  By the way, pome fruits are members of the plant family Rosaceae, sub-family pomoideae.

Despite the negatives just cited, the eastern redcedar has plenty of good qualities. It is:

• Resistant to extremes of drought, heat, and cold. Regardless of where you stand on the issue of global warming, this is a plant that can take such conditions with aplomb.
• Tolerant of a wide range of soils — poor dry soil, alkaline soil, and dry rocky outcrops, as well as wet swampy land.
• Tolerant of windy conditions, so much so that the species was planted as windbreaks to offset the dust bowl conditions of the 1930s.
• Salt tolerant, which means it can be used near roads, driveways, and sidewalks. It can tolerate brackish marshy sites in the southeastern part of Virginia and coastal sand dunes that are subject to salt spray.
• A significant source of food and shelter for wildlife. The blue fruits on the female trees are consumed by a wide variety of wildlife, including the Cedar Waxwing songbird, which is named for this tree.
• A moderate to long-lived evergreen. Some specimens have been known to live more than 500 years. Large specimens are often found in old cemeteries and other older, undisturbed properties.

PLANT PROFILE

Not to be confused with the western redcedar (Thuja plicata), which is native to the western U.S. and an entirely different species, the eastern redcedar is native to the eastern half of the United States. Hardy in USDA zones 2 – 9, it is widely distributed from Canada to Florida and west to Texas.
Below ground, an eastern redcedar seedling initially has a penetrating taproot. But as the plant ages, it develops an extensive shallow, fibrous root system enabling it to persist on outcrops and shallow soils. Above ground, the tree grows 1’ to 2’ per year on a single trunk. It matures at about 40’ to 50’ tall and 8’ to 20’ wide, becoming rounder with age. Very old specimens are capable of growing 80’ or more feet tall and 30’ or more feet wide. The national champion eastern redcedar, located in the Lone Hill Methodist Church Cemetery in Coffee County, Georgia, is 57’ tall with a 75’ wide crown spread.

Female eastern redcedar tree with masses of bluish berry-like cones

Eastern redcedars are dioecious, which means that male and female trees are separate plants. It’s easy to tell the difference between the two. While both bloom in late winter, female eastern redcedars produce green flowers and the males produce yellow flowers. The female trees bear small (quarter-inch), fleshy, berry-like cones that appear in spring and mature in the fall. The “berries” are generally blue with a whitish bloom, giving them a gray-blue appearance, and contain 1 to 4 seeds each. The male trees bear brown, pollen-bearing cones on the branch tips. Their pollen is dispersed by the wind.

The fragrant, scale-like foliage is sticky to the touch and can be coarse or fine-cut. It varies in color from gray or blue-green to dark green and tends to “bronze” In winter.

Scale-like Foliage of Eastern Redcedar Tree

TIMBER VALUE OF EASTERN REDCEDAR

First observed at Roanoke Island, Virginia in 1564, and described by the early colonists as “the tallest and reddest cedars in the world,” the eastern redcedar quickly became prized for building purposes. Finding the heartwood to be rot-resistant, the colonists used it to construct furniture, rail fences, poles, coffins, and log cabins. It is famously known for its fragrant oil, which is a natural insect repellant. Because the scent repels moths, the aromatic wood has been used for centuries in the construction of chests, closets, and wardrobes to protect woolen clothing. Redcedar sawdust or wood chips may also be used in kennel bedding to repel fleas and minimize odors.

Prior to 1940, pencils were made almost entirely from cedar but are now made from cheaper wood sources or synthetic materials.
In the past, eastern redcedars were commonly used as Christmas trees. While still used in parts of the south, the species is not extensively grown for this purpose anymore, possibly because it may be slower growing than other commercially grown evergreens. When used for decorations, it gives off a strongly scented perfume, making a house smell wonderfully festive.

VALUE FOR WILDLIFE

The dense branches of the eastern redcedar provide important refuge and shelter for song birds and game birds, such as quails, bobwhites, ruffed grouse, pheasants, and turkeys. Butterflies and small mammals also benefit from the cover this tree provides. The soft, silvery bark peels off in long, flexible strips which squirrels and other small mammals use in their nest materials. The berries are an important source of food for more than 50 bird species as well as a variety of mammal species, including rabbits, foxes, raccoons, skunks, opossums, and coyotes. The twigs and foliage are often eaten by hoofed browsers, such as mule deer and whitetail deer.

HERBAL PROPERTIES

Juniper berries, which are used to flavor gin, are purported to come from this species but, in fact, come from a related species, Juniperus communis. American Indians did make a tea from the twigs as a remedy for sore throats and coughs but the berries themselves are believed to be mildly toxic.

CULTURAL REQUIREMENTS

The cultural requirements for this tree seem to run counter to what most plants prefer. This tree can grow under conditions that would cause other species to crash and burn. While it can tolerate just about any growing conditions, other than full shade, it does best in deep, moist, well-drained alluvial soil with a pH value ranging from 4.7 to 7.8 and full sun to part shade.

PROPAGATION

Eastern redcedar is easily propagated by seed. In fact, birds and small mammals eat the berries and then “disperse” the seeds along fence lines, telephone lines, or other perching sites. Cultivars, however, need to be propagated from stem cuttings in order to get a clone of the parent plant.

PESTS/DISEASES

Apple-Cedar Rust Gall on Eastern Redcedar Tree

The eastern redcedar should be planted a minimum of 500’ away from apple trees. As previously mentioned, it is an alternative host for cedar-apple rust, a fungal disease that causes serious leaf and fruit spot damage on apple trees. The disease has a minor effect on the eastern redcedar itself. Galls containing the fungal spores appear on twigs in early April as tiny dimpled growths, ranging in size from 0.375” to more than 1” in diameter. Warm spring rains trigger the galls to produce gelatinous, orange, starfish-like protrusions called telial horns. The telial horns dry up and fall off with the arrival of dry weather but, by then, the rust spores will have floated away. The disease can be prevented from spreading to apple trees by spraying the galls in early April with a suitable fungicide.

Eastern redcedars are relatively free of serious pest and disease problems. They are, however, susceptible to bagworms, which should be picked off and destroyed before the eggs hatch. Don’t put the bagworms in the compost. The eggs can live in the compost and hatch out later. Seal them in a plastic bag and put them in the trash or place them in a pail of soapy water so that they drown.

EASTERN REDCEDAR SELECTIONS

A number of eastern redcedar cultivars have been bred to capture some of the more desirable aspects of the species. Many of the cultivars may be more suitable in modern landscapes than the straight species. Available in various shades of green or gray, the cultivars can be tall and narrow or short and spreading and several shapes in between. Just a few of the 34 cultivars listed in Michael A. Dirr’s Manual of Woody Landscape Plants include:

Eastern redcedar cultivar ‘Burkii’ at the U.S. Botanic Garden

• ‘Burkii’, a non-flowering male cultivar with a narrow, pyramidal shape ranging in height from 10’ to 15’ with a spread of 4’ to 10’. Although this cultivar has good resistance to the cedar-apple rust pathogen, it is best not to plant it near apple trees.

• ‘Emerald Sentinel’, a female eastern redcedar cultivar that produces abundant fruits. It has a narrow, conical-shaped form and grows about 25’ tall and 8’ wide. This cultivar generally retains its dark green color throughout the winter months. In 1997, the Pennsylvania Horticultural Society named this selection as a “Gold Medal” plant.  Described as one of the toughest plants available, ‘Emerald Sentinel’ is tolerant of extreme climatic and soil conditions.

• ‘Blue Arrow’, a small, upright, non-flowering cultivar with attractive blue-green foliage. This narrow, columnar tree only grows 15’ tall by 2’ wide, making it an excellent choice as a vertical element in a mixed border, a featured tree in a small garden, or as a hedge. Its shorter size also makes it a good choice under power lines.

• ‘Canaertii’, a conical female tree form with dark green foliage that takes on a brownish cast in the winter. This cultivar produces a heavy fruit set. It grows 30’ tall and 8’ to 15’ wide. Its habit becomes looser and more open with age.

• ‘Taylor’, a densely branched, columnar cultivar that typically grows 15’ to 20’ tall but only 3’ to 4’ wide. In higher elevations and dry sites, this cultivar develops more leaf wax, giving the foliage a silvery-blue color that stays attractive throughout the growing season. This cultivar has a formal look to it, similar to that of an Italian Cypress. The Missouri Botanical Garden selected this cultivar as a Plant of Merit for its outstanding quality and dependable performance. To quality for this honor, the plant needed to be easy to grow and maintain as well as have outstanding ornamental value.

‘Grey Owl’ cultivar — a shrub form of Juniperus virginiana

• ‘Grey Owl’, a broad, slow-growing shrub form with finely textured silvery gray foliage. This female form produces large amounts of berries on a compact, wide-spreading shrub that grows 3‘ tall and 6’ wide. This cultivar has good resistance to cedar apple rust.

• ‘Pendula’, a good specimen tree, which grows to 40’ tall and 15’ to 25’ wide. The branch tips droop, giving the tree a weeping habit. This female form features abundant blue, fleshy cones.

HOW TO USE EASTERN REDCEDAR IN THE LANDSCAPE

Use eastern redcedar as a specimen plant or in groups. Use it planted as a hedge, a border, a screen, or as a windbreak. It can even be clipped into a topiary form. Some of the smaller forms may be planted in large pots for display purposes or in a mixed shrub border. This species may be used in large rain gardens or on slopes to help stabilize soil.

SUMMARY

On the one hand, eastern redcedar is a native tree with many positive attributes that make it a desirable woody plant in the modern landscape. On the other hand, this plant can potentially have a negative impact in some ecosystems if it is not managed well. And therein lies the dilemma. In the past, controlled fires kept the tree from populating open fields. As human populations increased and spread across the country, controlled fires ceased being a viable option. In addition, many properties are no longer aggressively managed, resulting in conditions that are more ideal for the spread of this tree than in the past. As a minimum, the eastern redcedar can be a nuisance tree, particularly in open fields and abandoned properties where young seedlings are not regularly mowed or dug out. Worst case, it has the capacity to negatively impact certain ecosystems by crowding out other species. Those conditions notwithstanding, the eastern redcedar has three significant advantages going for it. It is able to withstand adverse growing conditions that many other tree species cannot tolerate. The rot-resistant heartwood makes it a very valuable timber tree. It is an important source of food and shelter for a wide variety of wildlife species. For these reasons alone, this species deserves a place in the landscape. In a controlled environment and in the right setting, it is a landscape asset worth having.

SOURCES

A Natural History of Trees of Eastern and Central North America (Peattie, Donald Culross, 1977)

Manual of Woody Landscape Plants, Sixth Edition (Dirr, Michael A., 2009)

Native Plants of the Southeast (Mellichamp, Larry. 2014)

“For the Birds, Butterflies, and Hummingbirds: Creating Inviting Habitats,” Virginia Cooperative Extension (VCE) Publication HORT-59, ext.vt.eduedu/HORT-59

“Trees and Shrubs that Tolerate Saline Soils and Salt Water Draft,” VCE Publication 430-031, ext.vt.edu/430/430-031

“Eastern redcedar,” Virginia Cooperative Extension Publication, pubs.ext.vt.edu/3010-1477

“Eastern redcedar,” dendro.cnre.vt.edu//factsheet (Virginia Tech Landowner Fact Sheet)

“Eastern Redcedar,” National Forest Service, na.fs.fed.us

“Juniperus virginiana,” Purdue University Center for New Crops and Plants Products,  www.hort.purdue.edu

“Juniperus virginiana,” University of Connecticut College of Agriculture, Health and Natural Resources Plant Database, Univ.of Conn. Plant Database

The Morton Arboretum, Fact Sheets, www.mortonarb.org/eastern-red-cedar 

The Pennsylvania Horticultural Society Gold Medal Plants, phsonline.org/gold-medal-plants/juniperus-virginiana

“Juniperus virginiana — Another Look,” The Scott Arboretum’s Gardenseeds blog, gardenseeds.swarthmore.edu//2011/juniperus-virginiana

“Juniperus virginiana,” Fire Effects Information System,(Anderson, 2003).  U.S. Department of Agriculture, Forest Service, www.fs.fed.us/database/feis

Olive Cheese Puffs

Having a crowd for the holidays? Need something easy to pass around with drinks while the roast is in the oven? If you love cheese straws and olives, then this throwback to the fifties, combining the two, is your delicious answer! You may freeze the unbaked cheese puffs on cookie sheets for about an hour, then pop them into freezer bags and take out just what you need whenever you want.

When I was in college, my boyfriend’s grandmother served these cheese puff appetizers to us every time we went to her house. This delectable combination of sharp cheese and salty olive resurfaces in my home around the holidays. A Google search turned up multiple sites with recipes for the retro favorites. The recipe that follows is a composite of having played around with many variations on a theme. You may use whatever type of olive you want, but most recipes call for the small green, pimiento-filled ones and I found them to be the best. Most recipes do not use an egg, but I found I preferred the consistency of the dough with the egg — not so crumbly. Many recipes call for pinching off bits of dough, but I love the suggestion of rolling and cutting out shapes — saved time and effort and gave a more consistent finished product.

 

In the photograph, I tried to capture the ease and simplicity of making

and serving these cheese balls–from rolling and cutting the dough,

to wrapping them around the olives  and placing on a baking sheet,

to serving them with a beverage of your choice. Bon Appetit.

 

 

 

 

 

Ingredients

8 Tablespoons (1 stick) butter

8 oz. (2 cups) grated extra-sharp cheddar cheese

1.5 cups unsifted all-purpose flour

1/4 teaspoon salt

1/4 teaspoon cayenne pepper or smoked paprika

Dash of Worcestershire sauce

1 large egg

1 jar (8 oz.) pimiento-stuffed Spanish green olives

 

Directions

  1. Drain the olives well, and dry them completely with a clean dish towel. Set aside.
  2. Beat the butter until creamy in a large mixing bowl; add the cheese and mix well.
  3. Stir the flour, salt, cayenne, and Worcestershire sauce until smooth. Beat the egg with 2 Tablespoons of cold water and add to the dough. Mix until just incorporated. Refrigerate for 30 minutes.
  4. Preheat oven to 400º.
  5. Once the dough is chilled, roll it out rather thin. Cut out squares or circles from the dough (I used an upended champagne flute). Settle the olive inside the circle and fold the dough around the olive.
  6. Place on ungreased baking sheet. Repeat with remainder of dough and olives. Bake until dough sets and balls are lightly browned, about 15 minutes. Serve hot.

 

The Ornamental Garden in December

The winter solstice in December brings with it the shortest days of the year and freezing temperatures. While that sounds like a downer, it also means the gardening season is officially over.  For the gardener, it’s time to reflect on the successes–and perhaps even failures–of this year’s garden and possibly start planning for next year’s garden.  Without weeds to pull, flowers to deadhead, or bugs and pathogens to fend off, we turn to our houseplants to satisfy the itch to garden.

Heavy December frost on ‘Gulf Stream’ Nandina foliage

 

 

WINTER HOUSEPLANT CARE

Overwintering plants indoors doesn’t have to be all that challenging.  You don’t have to be a “houseplant whisperer” to keep them healthy and vigorous. It’s simply a matter of understanding their requirements for water, humidity, temperature, and light.  If you ignore these essentials, you’ll find that it’s quite easy to kill a houseplant.  Let me count the ways:

  1. Overwatering (also known euphemistically as “killing with kindness”). This is considered perhaps the most effective way to kill a houseplant.  Overly saturated soil prevents the plant from taking up oxygen at the root level. Symptoms of overwatering include wilting and yellowing of the foliage.   The proper way to water a houseplant is to give it enough water so that it drains from the bottom of the pot.  Otherwise, salts in the water may build up in the soil, which will eventually harm the plant.  Unless your plant is one that prefers consistently moist soil, like an African violet, allow the soil to dry out somewhat between waterings.
  2. Lack of humidity. The flip side of overwatering is not having enough moisture in the air.  Once we turn the heat on in our homes, the humidity in the air drops to well below 50%, which is the moisture level that most plants need to stay healthy.  Browning of the leaf margins or tips generally indicates that the air is too dry.  To remedy this problem, place the houseplant in a bathroom or kitchen where steam from showers or from boiling water will raise the humidity level in the room.  Or, if you have a humidifier, try to position it near your houseplants.  Another solution is to fill a pebble tray with water and set the pots on top of the pebbles so that they are not actually touching the water.
  3. Exposure to direct heat. Avoid placing houseplants near a vent or other source of direct heat.  Hot air blowing on a plant can severely dehydrate it.  A plant that is overheated will appear very limp.
  4. Exposure to cold air. If your house is not well insulated or sealed against cold drafts, your plant can suffer from exposure to the cold temperatures.  You’ll have the same problem if you place a tender tropical plant near a door that is opened frequently.
  5. Direct contact with a window. Although most houseplants need as much light as possible, don’t let them have direct contact with a frosty window.  Otherwise, the foliage touching the glass may freeze.
  6. Not enough light. Plants that aren’t getting enough light will let you know by looking pale rather than a healthy green color. New growth will look tall and leggy or spindly rather than robust, and the new leaves may appear smaller than normal.  To solve the problem, move the plant to a brighter spot, preferably to a south or west-facing window.   Remember to give the plant a quarter turn about once a week so that it grows evenly and doesn’t lean or stretch toward the light.
  7. Pest problems. It may be wintry outside but that doesn’t mean you can assume plant pests are not an issue.  Pests such as white fly, spider mites, aphids, mealy bugs and scale can multiply very quickly on plants.  It pays to inspect your plants frequently for unwanted hitchhikers and deal with them promptly.

DECORATING FOR THE HOLIDAYS

One the best things about December is the chance to celebrate winter holidays and that means decorating the house with greenery. For many households, a favorite family activity is selecting and decorating a Christmas tree.  You may have noticed that Christmas tree lots appeared around town before Thanksgiving, which makes one wonder just how fresh those trees could possibly be.  For information on selecting and maintaining a cut Christmas tree, see Nancy Bolton’s excellent article on Holiday Decorating with Fresh Greenery, which appeared in the December 2015 issue of The Garden Shed.   Her article includes a table comparing the four most popular Christmas trees – Fraser Fir, White Pine, Scotch Pine, and Norway Spruce.  If you’re not sure which is which, here’s how to tell the difference:

  • Fir – If the branches bear their needles individually rather than in groups and if the needles feel flat to the touch, the tree is most likely a fir.
  • Pine – If the needles occur on the twigs in groups of two, three, or five, it’s a pine.
  • Spruce – if the needles have four sides and roll easily between your fingers, it’s a spruce.

If you want to do further research on Christmas trees, check out Virginia Cooperative Extension Publication 420-641, Selection and Care of Christmas Trees.   The National Christmas Tree Association website (realchristmastrees.org) is another good source for learning about the characteristics of conifers commonly used for Christmas trees.    Also, the National Gardening Association website (garden.org) has descriptions of the top 10 most common Christmas trees.

PREPARING YOUR LANDSCAPE FOR SNOW

Just because the past few winters here in Virginia have yielded minor snow accumulations, don’t assume we’ll have the same mild weather (translation:  little or no snow) this season.  It wasn’t that many years ago (2010, actually) that the northeast and mid-Atlantic regions received two heavy snow storms (dubbed “snowmageddon”) back-to-back, producing more than 3 feet of snow in Virginia.

Should we experience heavy snow or ice storms this season, take some precautions to prevent damage to your evergreen landscape plants. Species with multiple leaders are susceptible to snow and ice damage. The branches of Leyland Cypresses in particular are bad about splaying under a heavy snow load, and the damage is generally permanent.  Other evergreens that might also be damaged include arborvitae, upright junipers, yews, magnolias, boxwoods, and some hollies.  There are a couple of ways to minimize damage.  By loosely encircling the outside of the plant with jute twine, narrow rope or strips of cloth, individual branches can’t catch and hold much snow.  Another technique is to tie the main leaders together, high up on the side of the shrub.   The bindings may be left in place once the snow melts or left in place until new growth begins in spring.

Clemson Cooperative Extension’s Publication on Protecting Evergreens from Ice Damage recommends preventing the problem in the first place by selecting evergreens with a single trunk or leader.  Species with multiple leaders should be pruned to a single trunk or leader when the tree is young.

GARDENING RECORD KEEPING

Before the first snow flies and you lose all memory of how well your garden did this year, take a walk through your garden (preferably on a mild winter’s day) and take notes on what did well and what didn’t.  Before you forget where the spring flowering bulbs are planted, make a marker of some sort – it doesn’t have to be fancy – and stick it in the soil so that you’ll be able to find the bulbs next spring. This is a good time to make a list of plants that need to be divided, donated to a plant sale, shared with friends, or simply put out of their misery.

This is also a good time of year to inventory your seeds – the ones you collected and the packaged ones that are left over from previous years.  I find it handy to organize seeds by year.  Just write the year the seeds were packaged for sale in the upper corner so that you can instantly see how old the seeds are.  If you have a lot of leftover seeds, you might want to make a database of the seeds and the year they were packaged.  This system helps you keep track of what you have and may prevent you from buying duplicates you don’t need.   Then, next spring, before you start planting, do a seed viability test to see if the older seeds are still any good or whether they need to be tossed.

INSECTS – WHERE DO THEY GO IN THE WINTER?

Do you ever wonder where insects go once the weather turns cold? It turns out that they have a variety of strategies for surviving cold weather.  Monarch butterflies, for example, migrate to warmer climates.  Wooly bear caterpillars overwinter in the larval state under leaf litter.  Japanese beetle larvae burrow deeper into the soil to escape the cold.  Some insects, such as dragonflies and mayflies, overwinter as nymphs in streams or ponds. Yet others, such as praying mantids, overwinter as eggs.  Certain moths overwinter as pupae and then emerge as adults in the spring.    Lady beetles, wasps, and some butterflies, such as the Mourning Cloak, simply hibernate.  For an interesting and colorful article on insect strategies to survive winter weather, see the University of Minnesota’s publication on Tough Buggers.

FUN FACTS ABOUT PLANTS

Now that gardening season is over for the year, keep in touch with your inner gardener by learning a few fun facts about plant names. For example, approximately 200 plants have the word “wort” in their names.  This word, which is derived from the Old English “wyrt,” originally meant plant, herb, or root and was applied to the names of plants believed to have healing properties.   For example:

  • Lungwort (Pulmonaria), which has spotted leaves, was believed to cure lung diseases.
  • Liverwort got its name from the shape of its leaves, which resemble a lobed liver.
  • Spiderwort (Tradescantia) may have been used to treat spider bites.
  • Barrenwort (Epimedium) was believed to prevent pregnancies.
  • St. John’s Wort (Hypericum) was thought to ease symptoms of depression.

 

 

 

 

 

 

 

 

 

Reflections on the Winter Landscape

Piet Oudolf, a world-renowned innovative garden designer, believes “The real test of a garden is how it looks in winter, when the bare bones of the design are revealed.”  In other words, a garden should be designed to be interesting throughout the year and not just in the spring and summer seasons.  Furthermore, Oudolf asserts, “The garden in winter is an emotional experience.  You think in terms of decay and disappearing and coming back. You feel the life cycle of nature.”  His words remind us that life is indeed a cycle and all seasons of the garden are beautiful – or should be.

WHERE TO BEGIN

Without the brilliant color and fragrance of flowers or leafy foliage to excite the senses, we must look for other ways to bring life and energy to the normally dormant winter landscape.  Begin by critically assessing your views from indoors.  As you look out your windows, does your eye linger on any one specific plant or landscape feature?  Think about what makes the view interesting and imagine what you could change to make it more appealing.

In determining changes to make, it may be helpful to break the dormant season into thirds.  Once you think of winter in terms of mini-seasons, it’s easier to decide which elements to incorporate into the landscape to make it more vibrant and alive.

Frost-covered Echinacea seed heads add texture and interest in the winter garden.

  • In late fall/early winter, some deciduous trees and shrubs hang on to their foliage or fruits well into November or even early December, providing plenty of color and interest. A few examples include oakleaf hydrangea, fothergilla, some viburnum species, and a number of oak tree species.   Also, the seed pods and seed heads of many perennials add texture throughout the entire winter season.

    Winter color on Burford hollies at the Norfolk Botanical Garden

  • In mid-winter, conifers and broadleaf evergreens provide mass and substance to the landscape, transforming it from drab and sparse to rich and full. Deciduous trees and shrubs with fissured or colorful bark, unique growth habits, and persistent berries also provide plenty of mid-winter interest.

    Galantus nivalis (snowdrops) blossoms emerging through snow cover

  • In late winter/early spring, hardy winter-blooming plants such as witch hazel, hellebores, and snowdrops add unexpected color and drama to the winter garden.

COLORFUL CONIFERS AND OTHER EVERGREEN SPECIES

Conifers and other evergreen trees and shrubs are the mainstays of the winter landscape.  They bridge the seasons, providing reliable color and structure in the spring and summer garden and a foil for the vivid colors of autumn leaves.  A native holly, juniper, or magnolia can be a very effective centerpiece in the winter landscape.  Their persistent foliage and thick branching catch and hold snow, creating infinite visual interest.  Virginia Cooperative Extension (VCE) publications 426-605 and 426-607 (listed below under sources) offer information on the selection of conifers and broad-leaved evergreens.

When choosing a conifer or broad-leaved evergreen, keep in mind the various shades of green and how they will harmonize with other plantings throughout all four seasons.  For example, the needles of blue spruce (Picea pungens) and other blue-leaved evergreens can make a strong visual impact when paired with purple or burgundy-leaved plants.  The fine, lacy, golden thread-like foliage of golden false cypress (Chamaecyparis pisifera species) contrasts well with darker green conifers and lightens the composition.  Gray-green junipers offer a cooling, soothing presence in the landscape.  With careful consideration of the shades of green, one can create a rich tapestry of color using conifers and broad-leaved evergreens only.    If you’re color challenged, like many of us, Nancy Ondra’s award-winning (American Horticulture Society) book, Foliage, is an excellent resource for learning more about the role of foliage, texture, and color in the landscape.

In addition to conifers, many other woody and herbaceous species add color and texture to the winter landscape.  Examples include magnolia (Magnolia grandiflora and cultivars), boxwood (Buxus species), inkberry holly (Ilex glabra), camellia, skimmia (Skimmia japonica), sweet box (Sarcococca species), mountain laurel (Kalmia latifolia), rhododendron, and Japanese Pieris (Pieris japonica).  Some fern species, hellebores, heuchera, and yucca are also good perennial evergreen choices.

Plants with variegated or spotted foliage may be used singly as an accent plant or in groups to add interest in the winter landscape. Too much variegated foliage, however, can be distracting, so don’t overdo it.  English holly (Ilex aquifolium) cultivar ‘Argenteo Marginata’ and English boxwood (Buxus semperverens) cultivar ‘variegata’ are two examples of variegated plants that have dark green leaves edged in white.  Gold Dust Aucuba (Aucuba japonica) ‘variegata’ has deep glossy green leaves richly splattered with gold.

COLOR SELECTIONS FOR THE WINTER LANDSCAPE

While evergreen species are often considered the mainstay of the winter garden, there are many other options for enlivening the landscape. Suzy Bales, author of The Garden in Winter, wrote:  “Green in winter is to the garden what meat and potatoes are to the body:  comfort food.  Brighter colors—blue, red, and gold—are much more exciting, like sugary desserts, but best used in small amounts.”   With that advice in mind, a vast number of plants may be used to provide a pop of color here and there in the winter landscape.

Red is the easiest color to incorporate into the winter landscape, according to VCE Publication 426-228, Patriotic Gardens:  Red, White, and Blue in Fall and Winter Gardens.  As the name of the publication indicates, the emphasis is on patriotic gardens.  However, the plant choices listed include a number that apply to any winter landscape. For example:

  • Flowering dogwood (Cornus florida) sports clusters of red berries that persist into winter.
  • Scarlet Oak and Red Oak (Quercus coccinea and Quercus rubra) foliage holds its red color well in cold weather before eventually turning brown.
  • Red twig/red osier dogwood (Cornus alba and C. sericea) have bright red twigs that make a dazzling display, particularly in snow, but also when positioned in front of dark green conifers or other evergreens. The brightest colors are on the new growth.
  • Red chokeberry (Aronia arbutifolia) is one of many shrubs with red fruits that may persist into the winter months.
  • Witch Hazel (Hamamelis x intermedia ‘Diane’) has reddish ribbon-like flowers that bloom in late winter – a time when flowers of any kind are in short supply.
  • Fothergilla, which is related to witch hazel, holds its orange, gold, and red leaves into December. After the leaves finally drop, the zig-zag branches provide winter interest.

WINTER BERRIES AND FRUITS

A wide range of berry- and fruit-bearing woody plants thrive in Virginia, providing many options for adding color to the winter landscape.  For example:

Berry-laden branches of Ilex verticillata ‘Winter Red’ deciduous holly

  • Red: Evergreen (Ilex species) and deciduous (Ilex verticillata) hollies; some crab apple (Malus) cultivars, such as ‘Donald Wyman’; green hawthorn (Crataegus), such as ‘Winter King’; American cranberry bush viburnum (Viburnum tribolum), Skimmia (Skimmia japonica); and even staghorn sumac (Rhus).  Also, rose bushes are often overlooked as a source of color in the winter landscape.  Rose hips from Rugosa roses such as ‘Jens Munk’ or Fru Dagmar Hastrup’ and shrub roses such as ‘Bonica’ or ‘Carefree Beauty’ provide welcome red color as well as a source of food for wildlife. 
  • Orange or red-orange: Pyracantha species and orange-berried winterberry holly (Ilex verticillata ‘Aurantiaca’). Also, our native persimmon tree (Diospyros virginiana) has orange fruit that persists into the winter months.
  • Yellow or gold: Yellow-berried American holly, such as Ilex opaca ‘Aurea’; yellow twig dogwood (Cornus sericea species), such as ‘Arctic Sun’; flowering crab apple, such as Malus ‘Harvest Gold’; or deciduous holly (such as Ilex Verticillata ‘Winter Gold’).
  • Blue: Junipers (including eastern redcedar) and some viburnum species, such as arrowwood (Viburnum dentatum) and black-haw (Viburnum prunifolium).
  • Purple: American beautyberry shrub (Callicarpa americana). The vibrant purple berries persist into winter, provided birds don’t eat them first.
  • Black or blue-black: Black chokeberry (Aronia melanocarpa), inkberry holly (Ilex glabra), and fringetree (Chionanthus virginicus).  All three produce attractive black or blue-black berries and fruits that serve as a food source for birds.

When selecting plants such as these for winter color, bear in mind that some species, such as winterberries and certain viburnums, are dioecious, meaning the male and female blossoms occur on separate plants.  So, for berry or fruit production, it’s important to select both a female specimen and a compatible male pollinator.

THE NATURAL BEAUTY OF BARK

Bark is the “Rodney Dangerfield” of the landscape.  During most of the year, it does not get the attention and respect it deserves.  Instead, flowers and foliage receive all the glory and accolades.  But once the flowers fade and the leaves fall away, bark finally gets its turn in the spotlight.  Some deciduous trees and shrubs have richly colored, fissured, striated, peeling, or curling bark. However, we generally don’t pay much attention to it until winter.  Only then do we become aware of its texture, variety, and beautiful shades of cinnamon, brown, cream, or gray — all best viewed against a backdrop of snow.  A few examples of woody plants with interesting or colorful bark include the following:

Peeling bark on River Birch ‘Heritage’ trees

  • River Birch (Betula nigra) bark exfoliates into papery sheets and plates, exposing various shades of brown, cinnamon, and gray on the underlying inner bark. This 40’ to 70’ species is perhaps the most heat tolerant of the native species. Don’t confuse this species with the paperbark birch (Betula papyrifera), which has the whitest bark of all the native U.S. birches, according to Michael Dirr’s Manual of Woody Landscape Plants.  While a beautiful tree, the paperbark birch prefers the cooler temperatures of zones 2 to 6, whereas most of Virginia is in warmer USDA Zone 7.
  • Paperbark Maple (Acer griseum) bark sheds strips of cinnamon-color bark all winter. The older bark of this 20’ to 25’ native of China exfoliates, revealing beautiful cinnamon or reddish brown coloration. The large curls remain on the tree rather than falling to the ground.
  • Coral-bark maple (Acer palmatum ‘Sango-Kaku’) bark provides multi-season interest. The bright coral-red stems and branches aren’t all that noticeable until after the simple palmate leaves drop in autumn.  The colorful bark of this small 20’ to 25’ tall Japanese maple shows to best advantage when displayed against a backdrop of hollies or other dark green evergreens.
  • Lacebark Elm (Ulmus Parvifolia) bark has mottled patterns of gray, green, orange, and brown. The leaves of this 40’ to 50’ tall and wide Asian native tree are smaller than those of other elm species. Lacebark elm has good resistance to Dutch elm disease.
  • Lacebark Pine (Pinus bungeana) bark on this slow-growing Chinese conifer peels, revealing a mottled patchwork pattern of white, silver, olive green and purple. The species grows about 40’ to 50’ tall on average, although more compact forms are available, and sports bright green needles in groups of three.
  • Oakleaf hydrangea (Hydrangea quercifolia) branches and stems peel, revealing a cinnamon color and interesting texture on this native species.
  • Stewartia (Stewartia pseudocamellia) bark is reddish brown and exfoliates, providing interesting winter color and texture. This small, slow-growing non-native tree from Japan grows about 12’ to 40’ tall and 8’ to 25’ wide.
  • Sycamore (Plantanus occidentalis) bark is light grayish brown, flaking off in large, irregular, thin pieces, exposing mottled grayish to cream-colored inner bark. This fast-growing native tree is best given plenty of space because it will eventually grow 75’ to 100’ tall and wide.

REVEALING SHAPES AND FORMS – THE BARE BONES OF THE GARDEN

Sadly, most gardening references focus on the spring, summer and fall attributes of woody plants but seldom provide much information on their winter attributes.   Some woody plants are often not fully appreciated for their beauty until they drop their leaves, revealing striking branches, angles, and sculptural shapes that can make a significant impact in the landscape:

Weeping Pussy Willow (Salix Caprea)

  • Weeping forms. Any weeping form of tree or shrub can make a dramatic focal point or accent in the winter landscape.  The cascading branches and foliage add delightful grace notes and a pleasing contrast to more upright species.  Although very few trees have a naturally weeping form, mutations of both deciduous and evergreen trees have resulted in a number of weeping selections.  A few examples include:  Redbud (Cercis), flowering cherry (Prunus species), Japanese maple (Acer dissectum species), umbrella elm (Ulmus), and willow (Salix).  
  • Vertical forms. Incorporating a strong geometric shape to serve as a vertical accent can transform a landscape from ordinary to extraordinary, particularly if most plantings in the landscape are low-growing. Just remember to keep proportions in mind when combining vertical with horizontal forms so that the two planes are in harmony with one another.   Examples of narrow, columnar, or pyramidal forms include:  Arborvitae, (Thuja ‘Emerald Green’), juniper (Juniperus virginiana ‘Emerald Sentinel’), boxwood (Buxus sempervirens ‘Dee Runk’), or holly (Ilex crenata ‘Sky Pencil’).
  • Topiaries – Pruning shrubs or trees into topiary forms is another way to add winter interest. Exotic shapes and forms, such as the topiary fox and hounds found at Baltimore’s Ladew Botanical Garden, may well be beyond the average gardener’s skill set. However, it is possible to build on the topiary idea by simply pruning a boxwood into a perfect sphere and showcasing it in a square container.  Arborvitae species are commonly shaped into a spiral form.
  • Espalier – This ancient method of training woody plants into a linear shape against a flat surface is an especially effective way to create interesting textures in the winter landscape. Many forms of espalier exist, but two of the easiest to master are the horizontal cordon and the candelabra. Although commonly used on fruit trees, other plants that respond well to this treatment include firethorn (Pyracantha species), rose of Sharon (Hibiscus syriacus), some crabapple (Malus) species, camellias, and some smaller magnolia species.

OTHER LANDSCAPE ELEMENTS THAT SURPRISE AND DELIGHT

Texture is an all-important element in the winter garden.  Some plants that provide interesting branching, seed heads, or shapes in the landscape include the following:

Contorted branches of Harry Lauder’s Walking Stick shrub

  • Harry Lauder’s Walking Stick (Coryllus Avellana Contorta), with its contorted branching, is particularly eye catching in the winter landscape. Dressed in its green summer clothing, this is just an ordinary looking shrub with no particularly distinctive features.  But, once it sheds its leaves in fall, this shrub takes on a completely different personality.  Its unique branching truly makes this shrub one of the more interesting plants in the landscape. Plant it near a walkway where its contorted habit can be viewed up close.   
  • Corkscrew willow (Salix matsudana), also known as curly willow, is perhaps best known for attention-getting wavy branches that are often cut and used for dramatic elements in floral arrangements. This fast-growing tree grows 20’ to 30’ tall with a symmetrical, rounded crown. Attractive year round, it is hardy in USDA zones 4 – 8. Although the branches are susceptible to breakage and the tree is not particularly long-lived, the corkscrew willow’s charming and unique branching may make it worthwhile growing anyway.
  • Dried grasses, such as ‘Shenandoah’ and ‘Dallas Blues’ switchgrass (Panicum virgatum), ‘Karl Foerster’ feather reed grass (Calamagrostis x acutiflora), or ‘Little Bluestem’ (Schizachyrium scoparium) sway in the wind and add movement to the landscape. For best results, select grass species that won’t flop over in winter.  Also, avoid planting invasive species.
  • Dried seed heads and seed pods of many plants, including tall sedum species, Echinacea, Clematis, and Rudbeckia, glimmer when coated in ice. Dried hydrangea flower heads catch the snow and rattle when stirred by a breeze.  Dried milkweed (Asclepias) seedpods reveal attractive shimmery linings when split open, contrasting beautifully with the dark brown seeds.
  • Silvery plants add interest to the winter landscape by reflecting the light. A few examples include common sage (Salvia officinalis), lamb’s ear (Stachys bysantina), Russian sage (Perovskia), and even the whitish-gray spent foliage of catmint (Nepeta).  Korean fir (Abies koreana ‘Horstmann’s Silberlocke’) is an interesting conifer species with green needles that curl up exposing the silvery underside.

BLOSSOMS THAT BRAVE THE COLD

It may be hard to believe, but a few plants are capable of pushing the wintry envelope and blooming despite the cold weather.  While some bloom sporadically throughout the season, particularly on milder days, a number of plants start showing color in February and March, as winter edges closer to spring.

  • Winter-blooming shrubs include witch hazel (Hamamelis), which sports red, copper, or yellow blossoms, depending on the species or cultivar. On mild winter days, winter jasmine (Jasminum nudiflorum) offers pops of bright yellow blossoms that both startle and delight the casual passerby.  Often grown as a short hedge, winter jasmine’s arching branches look particularly fetching when allowed to cascade over a stone wall.  Other winter-blooming shrubs include Japanese Pieris (Pieris japonica), fragrant winter daphne (Daphne odora), pussy willow (Salix discolor), paperbush (Edgeworthia), and some cold-hardy camellia species.
  • A few perennials that bloom in winter include Lenten Roses (Helleborus orientalis) or Christmas roses (Helleborus niger), named for the time of year they bloom. They are not roses at all, but members of the Helleborus genus. Depending on the species, they start blooming from mid- to late winter and continue to bloom through spring.  A related species, bear’s foot hellebore (H. foetidus), has clusters of chartreuse flowers edged in dark red held high over darker green foliage.  All three Helleborus species, plus countless hybrids, have handsome leathery dark green foliage that sprouts in early spring, holds up well in summer heat, and persists through the winter months.
  • Many bulb species are also capable of braving the elements. Toward the end of winter – February and March – or even during a mild January, many bulbs provide color, including white snowdrops (Galanthus), bright yellow winter aconites (Eranthis hyemalis), or brilliant blue Siberian squill (Scilla siberica). Of course, nothing is more enchanting than the sight of a bright gold or purple crocus pushing up through a blanket of snow and ice.

THE ROLE OF HARDSCAPE FEATURES IN THE WINTER GARDEN

It’s perfectly normal to focus entirely on live plants as a way to invigorate the winter landscape.  However, one of the easiest and most satisfying ways to make the winter landscape interesting is to install a hardscape feature.  An interesting gate or archway makes a pleasing accent in the garden, prompting visitors to enter and explore. A well-placed bench invites one to linger and admire the view.  Stone walls, fences, curving walkways, terraces, and other permanent features serve as accents, focal points, backdrops or dividers. A graceful trellis, tuteur, or arbor adds a vertical element and can look particularly attractive when coated in a blanket of snow.  Permanent urns (weather-proof, of course), sculptures, kinetic art, birdbaths, birdhouses, and other ornamental objects can also add dramatic or whimsical elements.   With the strategic placement of a simple fountain, sculpture, urn, or small bench, the smallest patio garden can be just as fascinating as the largest estate garden.

DON’T FORGET THE VALUE OF WILDLIFE IN THE LANDSCAPE

Anything that adds motion to the landscape enlivens it and makes it interesting, no matter the season.  This applies to wildlife as much as it does to plant materials.  Plants with seeds, cones, or berries will ultimately attract birds and other wildlife species.  The flashes of color as birds dart from one food source to another, together with the furtive movements of other creatures, make the landscape come alive on so many levels.  This is perhaps the best of all reasons to create a vibrant winter garden.  In our fast-paced, technology-driven society, such a landscape re-connects us with the natural world and provides an instant balm for the soul.

SUMMARY

As I reflect on the winter landscape, I am reminded of a frigid December night nearly 50 years ago in a small Pennsylvania town near the Pocono Mountains. With Christmas only hours away, every house was festooned with bright twinkling lights and other colorful holiday decorations.  One house on the edge of town stood apart from the others, conspicuous by its lack of holiday decorations.  That home owner’s choice of decoration was a single spotlight positioned to shine up through the branches of a white birch tree in the front yard.  The spotlight caught the tree’s gleaming white bark, casting the tree branches in sharp contrast with the late night darkness.  That breathtakingly beautiful image, so unexpected and so startling, has stayed with me all these years.  To my mind, all the gaudy, bright Christmas decorations in the world could not compete with the sheer beauty and simplicity of that birch tree.  It doesn’t take much to make a winter landscape exciting and powerful – a conifer here, a berried shrub there, perhaps an urn, or just a simple spotlight.

SOURCES

Foliage (Ondra, Nancy J., 2007)

Manual of Woody Landscape Plants (Dirr, Michael A. 2009)

Planting Design – Gardens in Time and Space (Oudolf, Piet and Kingsbury, Noel, 2005)

Planting for All Seasons (Buchan, Ursula, 1999)

The Art of Gardening, Design Inspiration and Innovative Planting Techniques from Chanticleer (Thomas, R. William, and the Chanticleer Gardeners, 2015)

The Nonstop Garden (Cohen, Stephanie and Benner, Jennifer, 2010)

Viburnums – Flowering Shrubs for Every Season (Dirr, Michael A., 2007)

“Patriotic Gardens:  Red, White and Blue in Fall and Winter Gardens,” VCE Publication 426-228

“Problem-Free Shrubs for Virginia Landscapes,” VCE Publication 450-236

“Problem-Free Trees for Virginia Landscapes,” VCE Publication 450-237

“Selecting Landscape Plants: Conifers,” VCE Publication 426-605

“Selecting Landscape Plants:  Broadleaf Evergreens,” VCE Publication 426-607

 

 

Magical Repelling Powers of Marigolds — Myth or Fact?

Last July I was out in the vegetable garden, when a neighbor gardener approached and asked, “What are you doing?”  I responded, “Smashing Mexican bean beetle larvae.” My neighbor gave me a puzzled look, followed by a smirking smile, as if I was committing a gardening no-no. I just had to ask, “You’re not having a beetle problem on your green beans?” He smiled and said, “Of course not I plant marigolds with my beans, and they keep the bugs out of the bean patch.” WOW! Could this be the silver bullet in controlling this obnoxious pest?

Now that the gardening season is over and the cover crop is planted,  I’ve got a chance to catch my breath from sowing, planting, mulching, weeding and harvesting. Did I mention weeding? Anyway, now that I have a little time to reflect back on the garden season as to what may or may have not worked well, I’ve been returning to that conversation with my neighbor about the wonders of the marigold. The seed catalogs are starting to show up in the mail, and the planning for next year’s garden is in the beginning stage, so before ordering a ton of marigold seeds, now would be a good time to do a little research on the magical repelling powers of the marigold plant. I’ve heard marigold stories for years, how marigolds will repel every garden pest known to mankind, including bugs, snails, rabbits, ground hogs, and deer!  I’ve even heard that it has been used to target and kill selected weeds. This sunny annual has been employed as a companion plant for generations just to do that — repel pests from the garden. Do they really benefit the garden as a repelling machine or are they just pretty and their repelling powers just a gardening myth?

The Plant

Marigolds belong to the aster family (Asteraceae), genus Tagetes. Their natural range extends from the southwestern United States into Argentina, with their greatest distribution being in south central Mexico. Approximately 50 species are known, but in general, the three most common are African marigolds (T. erecta), French marigolds (T. patula) and Signet marigolds (T. tenuifolia). However, regardless of their name, all marigolds are native to subtropical America and have been cultivated in Mexico for over 2,000 years.

Tagetes patula, commonly called French marigold, is a compact annual that typically grows 6-12” tall and features single, semi-double, double or crested flowers (1-2” diameter) in shades of yellow, orange, red and bicolor. Their pinnate leaves with toothed, lance-shaped leaflets are aromatic.

French Marigold (Tagetes patula)

Tagetes erecta, commonly called African marigold, Aztec marigold, American marigold or big marigold, is native to Mexico and Central America. Big marigold may be the most descriptive of its names because plants are noted for their large flowerheads. They typically grow from 1-4’ tall and feature huge, mostly double-globular flowers (2-4” diameter) in various shades of yellow, orange, and white. Foliage and flowers are aromatic when brushed or crushed. Triploid F1 hybrids (T. erecta x T. patula) combine the large flowers of the African marigold with the more compact size of the French marigold into vigorous plants with 2-3” diameter flowers on stems reaching 10-18” tall. These triploids are largely unaffected by high heat and usually bloom all summer.

African marigold (Tagetes erecta)

Tagetes tenuifolia. Signet marigolds are compact, mounding plants with smaller flowers and leaves than most other marigolds. Yellow, orange, golden, or bicolored flowers are held either well above the fine-textured, dark green foliage or tucked in with the foliage, depending on the cultivar. This plant doesn’t have that overwhelming marigold scent but has a light, citrusy smell.

Signet marigolds (Tagetes tenuifolia)

Fact or Fiction

Corn earworm on marigold

For generations, many vegetable gardeners have planted marigolds in their vegetable patches to repel pests. However, there is a lack of scientific evidence to support the notion that marigolds actually repel pests. Research conducted at Rutgers University concluded that marigolds failed to repel cabbage, carrot and onion pests.  In fact the USDA lists a total of 15 pests that attack marigolds; included on their list are aphids, Japanese beetles, snails, and spider mites,  just to name a few.  On the other hand, researchers at the University of Vermont have reported that marigolds have been effective in luring pests away from other ornamental plants.

Although science has yet to prove that marigolds actually repel pests from vegetable crops, there is scientific evidence  that marigolds CAN be an important tool in controlling certain nematodes.   Nematodes are tiny worms, usually microscopic in size. Nematodes that feed on plants — called plant-parasitic nematodes —  have spear-like mouthparts used to puncture plant roots to obtain nutrients.  As a result, plant-parasitic nematodes can seriously damage or even kill crops, turf, and ornamental plants.

How marigolds help fight nematodes

Marigold roots release a toxic chemical  (alpha-terthienyl), and the presence of this chemical inhibits the hatching of nematode eggs.   Therefore, control of the nematode population is achieved by interrupting the nematode life cycle.

One drawback with using marigolds for nematode control is that the benefit is not realized until the following year. To be effective the marigolds must be planted before the vegetable crop — at least 2 months before — and must be planted at the same location where the vegetable crop is to be planted; otherwise, no benefits will be gained from the marigold root exudates.  For example, California research showed that tomatoes grown after marigolds had significantly lower numbers of root galls due to  root-knot nematodes (Meloidogyne incognito).  In addition, the tomato yields were higher (root length, shoot weight, number and weight of fruits were all higher in plants grown after Tagetes).  UniversityofCaliforniaRiverside.edu. 

Varieties Matter

Care should be taken when purchasing marigolds for controlling nematodes.  That’s because “not all marigold varieties control all types of nematodes.”  Univ.ofFlaExt.edu/ng045.  For example, the California research mentioned above revealed that particular varieties are more effective at controlling root-knot nematodes.  In that experiment, the “Single Gold” variety of Tagetes patula outperformed other varieties.  You’ll get the best results if you determine which types of nematodes are in your local soils, and you can do this by sending soil samples to a nematode assay laboratory.  Univ.ofFlaExt.edu/ng045 (look at the chart in this article identifying marigold species and varieties by their resistance to and effectiveness against particular types of root-knot nematodes).

Attracting Beneficial Insects

In addition to helping control nematodes, marigold flowers attract beneficial insects that not only pollinate, but also help control bad bugs. Beneficial insects attracted to marigolds include: hover flies, lady bugs and parasitic wasps.

Conclusion

To date there is very little scientific evidence that the aroma of the marigold plants actually repel pests, however it is a generally accepted scientific fact that marigolds help to control nematodes and attract beneficial insects that aid in controlling unwanted pests.

There is growing  concern about pesticides’ non-target effects on humans and other organisms, and many pests have evolved resistance to some of the most commonly-used pesticides. Together, these factors have led to increasing interest in non-chemical, ecologically sound pest management. The marigold is not only pretty but offers the gardener another arrow for the quiver in the bug war.  Who wouldn’t want to plant a beautiful plant that was edged out by the rose for our national flower. I know I will!

Thanks for stopping by The Garden Shed.   We members of The Garden Shed Team wish you and your family a safe and happy holiday season.

Sources:

“Tagetes L., Marigold,” Plant Profile, USDA https://plants.usda.gov/core/profile?symbol=TAGET

“Tagetes erecta, ” Missouri Botanical Garden, http://www.missouribotanicalgarden.org/PlantFinder/PlantFinderDetails.aspx?taxonid=277371

“Effects of Selected Marigold Varieties on Root-knot Nematodes and Tomato and Melon Yields”, Department of Namatology, University of California, http://faculty.ucr.edu/~atploeg/PDF PAPERS/PLANT DISEASE/PLANTDISEASE.pdf

“Marigolds (Tagetes spp.) for Nematode Management,” University of Florida Institute of Food and Agricultural Sciences, Univ.ofFlaExt.edu/ng045.

“Companion Planting and Insect Pest Control,” Rutgers University, http://pemaruccicenter.rutgers.edu/assets/PDF/publications/2013-InTech-Companion_planting_and_insect_pest_control.pdf

“Murdering Thrips with Marigolds, Fungi & Mites,” University of Vermont Entomology Research Laboratory, https://www.uvm.edu/~entlab/Greenhouse IPM/Workshops/2015/AFEProjectDesc&SummaryDec2014.pdf

“Root-knot Nematodes: Biocontrol with Marigolds,” North Carolina Cooperative Extension, https://carteret.ces.ncsu.edu/wp-content/uploads/2013/07/Root-Knot-Nematodes-Biocontrol.pdf?fwd=no

“The Repellent Marigold And Other Myths Of Companion Gardening,” The Chicago Triburne, http://articles.chicagotribune.com/1992-09-13/news/9203230490_1_companion-plantings-carrots-love-tomatoes-bedding-plants

“Dispelling Marigold Myths,” Alabama Cooperative Extension System, http://www.aces.edu/dept/extcomm/specialty/marigolds.html

“Parasitic Wasps: A Gardener’s Best Friend,” North Carolina Cooperative Extension, https://brunswick.ces.ncsu.edu/2014/04/parasitic-wasps-a-gardeners-best-friend/

“PROMOTING THE MARIGOLD AS NATIONAL FLORAL EMBLEM,” The Dirksen Congressional Center, http://www.dirksencenterprojects.org/promotingmarigold.pdf

“Controlling Insects on Flowers,” USDA, https://naldc.nal.usda.gov/download/CAT87210014/PDF

2003 Annual Report of Accomplishments and Results, The Connecticut Agricultural Experiment Station, https://portal.nifa.usda.gov/web/areera/Reports/2003/Ct/AES.NewHaven.CT.pdf

“Attracting Beneficial Insects, Penn State University,” https://extension.psu.edu/attracting-beneficial-insects

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

The Vegetable Garden in December

Happy holidays from The Garden Shed!  You’ve completed all your Christmas shopping and done all your decorating, so now you’re looking for a few gardening tasks. Right?  Well, here’s our list of December tasks and tips for the edible garden:

  • Looking for a gardening gift for that friend who has everything? Consider a gardening journal. Winter is a good time to start a garden journal and document all the trials and triumphs of the gardening season. When the mailbox gets deluged with seed catalogs for next season, your friend will have a record to refresh his or her memory about which seeds to order and which to avoid.
  • If your soil test shows a need for raising the pH, apply dolomitic limestone now so the winter rain and snow can move it into the ground.
  • If you have run out of sage, or just want a different flavor, substitute savory or rosemary in your turkey recipe.
  • Use a combination of red and green sweet peppers frozen from last summer’s garden to give holiday food a seasonal flair.
  • If you are planning to lay out newspapers as mulch next spring, glue them end-to-end this winter and store them in rolls. When needed, the paper mulch unrolls easily and won’t be lifted by the wind before they can be anchored.
  • There are several herbs that can be grown in pots in the home during the winter. Parsley is one of the most widely-grown herbs in home gardens and can serve as a houseplant during the winter. The plant will provide fresh green leaves for garnishing or flavoring for egg dishes, soup, fish or potatoes. Chive plants can also be grown in pots during the winter. The leaves are used to season soups, salads and stews. Finely chopped leaves add delicious flavor to sour cream for dip or salad dressing. Plant seeds in pots filled with rich, well drained, and sterilized potting mix. Cover the pots with plastic bags or clear wrap until germination occurs. Put the pots in a warm room, in a sunny, southern window and keep the soil moist.
  • You still have time to make herb vinegars with chives, shallots, garlic or any herbs on your windowsill. Use approximately 4 ounces of fresh herbs to 1 quart of wine or rice vinegar. Allow the herbs to infuse for at least two weeks.
  • Don’t forget to use some of those vegetables still out in your garden: carrots, turnip greens, kale or other hardy vegetables.

The Garden Shed team hopes you and your family have a safe and happy holiday season.  We look forward to your visits to The Garden Shed in 2018.

Source:

Adapted from The Virginia Gardener by Diane Relf