The Garden Shed

A Community Newsletter published by the Piedmont Master Gardeners

June 2016-Vol.2 No.6


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Who We Are

We are members of the Piedmont Master Gardeners, which simply means we have all been trained to share the scientific expertise of Virginia Tech and the Virginia Cooperative Extension Service. More important, we are your friends and neighbors with a passion for gardening – and learning more about it. MORE

Table of Contents

Pasta Primavera with Asparagus and Peas

Toss garden veggies with pasta for a satisfying meal!

Grasscycling-Let the Clippings Fall

Good for the environment

The Vegetable Garden in June

WOW what a spring.....

The Ornamental Garden in June

As spring planting winds down, it's time to focus on maintaining the ornamental garden.

Sweet Potatoes

Is it a yam or a sweet potato?

Asclepias — Or How I Learned to Love Milkweed

Asclepias -- a common weed but a worthy addition to the ornamental garden!

Growing Things When the Rains Don’t Come

That wasn't our May, but may be the summer.

Sweet Potatoes


The sweet potato (Ipomoea batatas) a member of the Convolvulaceae or morning glory family, is one of several native American plants discovered by Christopher Columbus and his shipmates on one of their American voyages, and Mr. Columbus and crew are given credit for transporting sweet potatoes back to Europe. However, the origin of sweet potatoes did not commence with Christopher Columbus’s discovery. The earliest cultivation records go way back to around 850 BC in Peru, and some archeological evidence suggests the cultivation of sweet potatoes may have begun around 2500-1850 BC. By the time Christopher Columbus arrived in the new world in the late 15th century, sweet potatoes were well established in the Americas.

Benefits and Uses

This South American and Central American tropical crop is remarkably nutritious and versatile; often referred to as one of the super foods, it is high in calcium, potassium, vitamins A and C, iron, and thiamine. It is low in sodium and is a good source of fiber and other important vitamins and minerals. A complex carbohydrate food source, it provides beta-carotene which may be a factor in reducing the risk of certain cancers. Sweet potatoes contain no fat and are a healthier alternative to white potatoes, which have a high glycemic index , meaning that starch from white potatoes are quickly metabolized, leading to a rapid increase in blood sugar. Sweet potato starches are metabolized at a slower rate. They can be eaten raw, boiled, baked, used in soups, desserts, breads, or stir-fries- and don’t forget that southern classic, homemade sweet potato fries!

A little known fact about sweet potatoes is that its leaves are edible, so they can be added to fresh garden salads, steamed like spinach or kale, or used in stir-fries. And the list goes on and on. In the early 1900’s George Washington Carver developed over 100 products using sweet potatoes —  ranging from flour to writing ink. And in recent years one North Carolina entrepreneurial farmer developed a creative use for sweet potatoes by processing them into an adult beverage.

Temperature Requirements

Unlike potatoes, which like cool weather, sweet potatoes enjoy hot weather and can be grown in the home garden with little difficulty. One of the keys to growing sweet potatoes is patience.  Do not plant too early; they need hot weather. The soil temperature should be above 65º F before planting this crop, and the plants need sun — lots of it — about 10 hours, in fact.

Sweet Potatoes in Virginia

Our state has a long history of growing sweet potatoes, as they were first cultivated in Virginia in 1648, possibly even earlier.  Did you know that George Washington was a sweet potato farmer before he became a general and the first the first U.S. president?  So if you want to add a little Virginia tradition to your vegetable garden this year, there’s still time. According to the Virginia Cooperative Extension Publication No. 426-331 we can plant sweet potatoes in our area up to the last week in June.


Examples of Sweet Potatoe Varieties Photo Source: North Carolina Sweet Potato Commission

Examples of Sweet Potato Varieties
Photo: North Carolina Sweet Potato Commission

There are hundreds of varieties of sweet potatoes, in colors ranging from white, orange, and red to purple. Virginia Cooperative Extension Publication No.426-480 recommends the following varieties for our area: Centennial, Jewel and Barker.

Soil and Fertilizer Requirements

Historically, sweet potatoes have been a poor soil crop that produces a decent harvest, however; well-drained sandy or clay loam soil yields sweet potatoes with better root shapes. Heavy or clay soils often yield rough or irregular root shapes. Sweet potatoes tolerate acid soils and perform best with soil pH of 6.0 to 6.5. It is best to base fertilizer applications on the results of a soil test. If a soil test has not been taken, the recommendation is to apply 3 pounds of 5-10-10 fertilizer per 100 square feet or the equivalent amount of organic fertilizer. After the vines begin to run, in about 3-4 weeks, sidedress with 4 pounds of 5-10-10 fertilizer per 100 feet of row. Be careful with the amount of fertilizer applied as over-fertilized sweet potato plants produce excessive amounts of foliage, resulting in smaller-sized potatoes.


Sweetpotato slips

Sweet potato Slips

Sweet potatoes are propagated vegetatively rather than from seeds and are typically started from transplants, which are called “slips.”  Slips are baby plants that are sprouted from a mature sweet potato. While you can grow sweet potato slips yourself, it is always a good ideal to start out with certified disease-free plants or vine cuttings from a reputable garden supplier.  If you have soil with a high clay content it is recommended to plant the slips on a ridge or “pseudo raised bed.”  Till the soil and build a pseudo raised bed (high ridges), about 10 inches wide and

Pseudo sweet potato raised bed

Raised bed for sweet potatoes

10-12 inches high with flat-topped ridges, spaced about 4 feet apart. Then plant the transplants with 8 to 12 inches between plants at a depth of 3 to 4 inches.

Sweet potatoes require at least 1 inch of water per week to grow well. Watering is especially important during the period right after transplanting — which is the establishment and root-development period. In general, weeds can be controlled by mulching between the row s with straw, clean (weed free) grass clippings or leaves. Once the vines begin to run, they usually will shade out weeds.


Sweet potatoes are usually ready to harvest in 90-120 days, depending on the variety. The tops usually begin to turn yellow as it gets close to harvest time. In any event, they should be harvested before frost.  Once the soil cools to around 50 degrees F, the quality and storage life of the sweet potato is reduced.

One word about digging sweet potatoes —  you cannot be too gentle! Carefully loosen the soil with a digging fork and gently pull the potatoes from the ground by their crowns. The skin on sweet potatoes is very thin, and extreme care should be taken during digging and handling to avoid skinning and bruising the roots. Even a very small wound can become infected with decay organisms. I have a gardening friend that lines the container with rags to avoid bruising or scratching the potatoes.  Also,  avoid direct exposure to sunlight for more than 30 minutes — that much sun may cause sunscald, which renders the sweet potatoes more susceptible to rot during storage.


Freshly dug sweet potatoes are considered to be “green” — not the color green, but uncured — and are not very sweet and moist.  In this uncured state, sweet potatoes have a shortened storage life. After the roots are dug, the curing process should begin within an hour or two. The curing process is required to bring out their sweetness, improve their nutritional value, and increase their storage life. During the curing process, starches are changed to sugar and a protective skin (periderm) develops, which thickens over wounds and creates a barrier to pathogens. To cure, place the sweet potatoes in a warm, humid room for 5 to 10 days at 80-85ºF and a high relative humidity — about 80 to 90%. These exact conditions may be hard to establish around the home, so select a location that comes close to these conditions. A general rule is that the lower the temperature, the longer the curing time; for example, a curing temperature of 65-75ºF may extend the curing period to 14-21 days.


After the sweet potatoes are cured, move them to a dark location where a temperature of about 60-65ºF can be maintained. Sweet potatoes are subject to chilling injury, so they should not be refrigerated. Properly cured and stored sweet potatoes can last for up to 10 to 12 months under ideal conditions.

Is it a sweet potato or yam?


Sweet Potato (Left) vs.  Yam (Right) Photo: North Carolina Sweet Potato Commission

 What do sweet potatoes and yams have in common? If you are a botanist, absolutely nothing! They are completely unrelated. Sweet potato (Ipomoea batatas) is part of  the Convolvulaceae family, and, like it cousin the morning glory, is a dicot (two embryonic seed leaves), and native to South and Central America. Whereas, the yam is in the Dioscoreaceae family, along with onions, lilies and grasses,  is a monocot (one embryonic seed leaf) and is native to West Africa. Sweet potatoes have a smooth thin skin and the yam has a rough scaly skin. The list of differences goes on and on.

Sweet Potatoe Canned yams

“Candied Yams”

So how did this confusion come about? Well, it may have started several hundred years ago with the West African word nyami, referring to the starchy, edible root of the Dioscoreaceae family.  The word nyami became “yam” in America — and was used by some people to refer to sweet potatoes, which do have some similarities to the nyami found in West Africa.

To add to the confusion, in 1937 the state of Louisiana coined the term “yam” as part of a marketing campaign to differentiate Louisiana-grown sweet potatoes from other sweet potatoes grown on the East coast. In 1937, the Louisiana sweet potato became a yam!

Today the terms sweet potato and yam are generally used interchangeably; the USDA requires that sweet potatoes labeled as “yams” always be accompanied by words “sweet potato” to differentiate them from true yams.

So what’s the difference? It may just depend on who you ask. If you ask a botanist the general response would be along the lines of: “They are totally different; they have nothing in common; if is grown in this county it is a sweet potato, not a yam.”   And indeed, the nyami is not as moist and sweet as a sweet potato.  On the other hand, if you asked a marketing person, you might get a response something like, “ All sweet potatoes are yams, but not all yams are sweet potatoes.” With that being said, it certainly clears up the confusion!

The sweet potato is truly a versatile vegetable; it is one of the few vegetables that can be featured as a vegetable or as a dessert. It is fairly easy to grow, with few pest or disease problems in our area —  with one exception:  deer love the vine. If you have a problem with dear in your garden, you’ll need to protect this wonderful vegetable.

Thanks for joining us in The Garden Shed.  We hope you drop by again next month.


“A Sweet Potato History,” Library of Congress website,

The Worlds Healthiest Foods,” What’s New and Beneficial about Sweet Potatoes”,

N.C. State University, Perspectives on Line, “Research reveal Sweet Potatoes are weapon against diabetes,”

“Yes, you can eat sweet potato leaves,” The Minnesota Project (, June 26,2012) ,

“Carver Sweet Potato Products,” Tuskegee University,

“Farmer turns leftover sweet potatoes into award-winning vodka,”   Red & White For Life, (N.C. State Alumni Association, Oct. 29, 2013)

“Sweet Potato,” Clemson Univ. Extension, Publication No 1322, ,

“Vegetable Planting Guide and Recommended Planting Dates,” Virginia Cooperative Extension Publication No. 426-331,

“Vegetables Recommended for Virginia, ”Virginia Cooperative Extension Publication No. 426-480, ,

“Sweet Potato Louisiana’s Most Popular Vegetable,”

“Home Garden Sweet Potatoes,” University of Ga. Coop. Extension, Publication C1014,

Purdue University Consumer Horticulture, “Dig those Sweet Potatoes”,

“How to Grow Sweet Potatoes,” North Carolina Sweet Potato Commission, ,

“Curing and Storing,” North Carolina Sweet Potato Commission, ,

“Curing and Storing Sweet Potatoes,” LSU AgCenter,

N.C. Cooperative Extension, “ What is the Difference Between a Sweet Potato and a Yam?”

“Sweet Potatoes,”Clemson Extension, Publication HGIC 1322


The Vegetable Garden in June

WOW,  what a spring we had in central Virginia. In April we had very little rain, and, well, May just made up for it with a deludge of rainfall. Naturally, a lot of planned planting got pushed out to June. And guess what, June is already a busy month in the vegetable garden — there’s planting, weeding, mulching, harvesting, looking for that little extra space to plunk in that one more pepper or tomato plant. Did I say weeding?

But let’s start with planting. June is a good month for planting beans and squash and plenty of other vegetables. Take a look at the handy-dandy chart below, which was developed using the  Virginia Cooperative Extension Publication 426-480, “Vegetable Planting Guide and Recommended Planting Dates.”

June 1-6 June 7-13
Bush Beans Bush Beans
Pole Beans Pole Beans
Lima beans Lima beans
Wax Beans Wax Beans
Cucumbers Cucumbers
Egg Plant* Egg Plant*
Muskmelons Muskmelons
Okra Okra
Peppers Peppers
Pumpkins Pumpkins
Southern Peas Southern Peas
Sweet Corn Sweet Corn
Summer Squash Summer Squash
Winter Squash Winter Squash
Sweet Potato Sweet Potato
Tomatoes* Tomatoes*
Watermelon Watermelon
June 14- 20 June 21-30
Bush Beans Bush Beans
Pole Beans Pole Beans
Lima beans Lima beans
Wax Beans Wax Beans
Cucumbers Cucumbers
Egg Plant* Egg Plant*
Muskmelons Muskmelons
Okra Okra
Peppers Peppers
Pumpkins Pumpkins
Southern Peas Southern Peas
Sweet Corn Sweet Corn
Summer Squash Summer Squash
Winter Squash Winter Squash
Sweet Potato Sweet Potato
Tomatoes* Tomatoes*
* Denotes Transplants
The suggested dates may vary for different areas.

June Tasks

  • Thin the seedlings of carrots and beets to proper spacing, about 4-5 inches to avoid crowding.
  • Apply organic mulches such as leaves, straw and clean grass to conserve water, suppress weed germination, and enrich soil as the mulch decays.
  • Repeat plantings of corn and beans to extend the harvest season.
  • Monitor soil moisture. As a general rule, vegetables require about an inch of water per week during the growing season. Soaker hoses or drip irrigation make the most efficient use of water during dry spells.
  • Asparagus — stop harvesting when spears become thin.
  • Growing lettuce under a shade screening material will slow bolting and extend the harvest season. Also try planting bolt-resistant varieties such as Muir, Sierra and Nevada.
  • Sow new warm-season vegetable seeds after harvesting cool weather crops.
  • Continue to mound soil up around the potatoes to prevent them from being exposed to the sun and turning green. You can also add a layer of straw or leaf mulch to help control weeds.

Some soils in our area are magnesium deficient, especially those where high-calcium lime has been applied rather than lime containing magnesium (dolomite). “Green” your peppers by giving them a magnesium boost with Epsom salts. This will aid fruit production. Dilute one tablespoon of Epsom salts in a quart of water. Spray the solution on leaves using a clean household spray bottle. You will notice a difference in the color of the leaves in couple of days.


Herbs planted in average soil need no fertilizer. Too much fertilizer may reduce flavor and pungency.

To control ear-worms on corn plants: apply several drops of mineral oil to the corn silk.

Thin overloaded fruit trees; this will result in larger and better fruit at harvest time.

You may have noticed your strawberries have a milder favor than normal this year. The problem could be the result of the excessive rainfall we had in May; it could have diluted the flavor of the berries. That heavy rain increased the risk of fungal problems, too.  I am experiencing higher than normal loss due to fungal diseases because of the wet weather.

Renovate the strawberry patch after harvest. Mow the rows, thin out excess plants and apply mulch for weed control.


Adapted from the Albemarle/Charlottesville VCE Office, “Monthy Horticulture Tip Sheets”,





Growing Things When the Rains Don’t Come

Any gardener who takes a summer vacation knows the impending disaster if plants go without water for even a week of broiling days.  The critical periods come at different seasons for each plant, but generally germination, bloom time and fruiting absolutely demand adequate moisture in order for vegetables, lawns and ornamentals to prosper.  In addition, some species tolerate dry spells better than others.  A deeply rooted woody plant or an established stand of grass may survive a drought for a couple of months while most annuals want watering at least once a week.  Here’s a rundown of summer strategies for keeping your garden and yard alive with moisture.

Mulching  The simplest approach is to wait for rain to fall; but that’s too passive for those of us who want consistently beautiful and tasty results.  Summer heat and windy weather any time of year will quickly dry out soil unless we mulch.  For our vegetables — where appearance is less important — we can put down several layers of newspaper,  which we cover with some other mulching material.  Newspaper decays in a couple of months and today is printed with ink more friendly to the environment.

A wide variety of mulching materials are available:

  • Raw wood chips or sawdust will decay slowly and initially uses up nitrogen, although each is sometimes available for free from local tree trimmers.
  • Green grass clippings hold moisture but produce a stinky mess as they deteriorate so mix them with another media.
  • Pine bark is beautiful although it scatters too easily for my taste.
  • Pine needles are more stable and lower the soil’s pH, making them useful around our acid-loving berries and azaleas.
  • Ground hardwood bark comes in brown, red or black, the first choice for flower beds.
  • Landscaping cloth, covered with another material for aesthetic purposes, is durable and also retards weeds.  Be aware that planting over the cloth later will require cutting it with a sturdy tool.

Finally, synthetic chips are brightly colored for your fancy, but since they do not decay, they add nothing to enrich your dirt.

Transporting Water.  A watering can is the iconic symbol of the gardener.  But who takes the time to sprinkle more than a few pots or new additions?  Nonetheless, a clever friend found she could extend her season for fresh lettuce by giving her plants a daily afternoon shower, cooling them just enough to stay happily productive.  Some of us save dishwater to pour on recently transplanted shrubs or trees; but be cautious about the additives in soap.  The other time-honored method of getting water where it’s needed is using a hose.  As straightforward as watering might seem, I’ve discovered there are better and worse ways of hosing down your growing things.

Tips for Effective Watering with a Hose

A 5/8 inch hose of good quality will last longer with a support around the female end that attaches to the supply, since the better hoses don’t kink and develop leaks.  Because they are heavier to lug around, they are best used where you can leave them in place for the season.  Installing rounded hose guards at critical locations can protect your finest garden specimens from damage when dragging a heavy hose through the garden.  Few accidents are more discouraging than breaking off a tomato plant by pulling too hard on your hose.  Decorative guards are sold in shops, although a heavy broomstick driven into the ground serves the same purpose.  A pistol grip valve on the business end of your hose can control the amount of water and how it’s dispersed as well as save your steps back and forth to the faucet.

Other irrigation systems for watering have some technological advantages.  Overhead sprinklers — often fixed atop a pole — will cover taller plants.  Such a system seldom develops problems.  It’s great for folks with unlimited water.  The disadvantage is the amount of water going where it’s not needed and the high percentage lost to evaporation.  Several micro delivery techniques have been devised.  One method buries multiple smaller hoses with closed ends, sometimes one per plant,  each hose having tiny holes punched along its length.  These small tubes are connected to a larger hose also buried in the ground and fitted with an automatic valve at the supply to turn on the water as often as desired.  I’ve seen this done for foundation plantings around a newly constructed home.   This system is ideal for newly-planted shrubs.  It could be used for any garden, although planting or cultivating around buried hoses would be problematic.

Micro-emitters laid on the surface can be easily moved.  I’ve used a small soaker hose made from recycled materials that can be placed alongside a row of vegetables or wound through an ornamental garden.  Perhaps because of the material or the multiple penetrations or the need to move them often, these hoses usually last only a season or two before breaking apart.  Another design uses a flat ribbon with small holes.  Unfortunately, all the micro-emitters are subject to clogging, again limiting the product’s life.

Before settling on an irrigation system, consider:

  • Distance from your water source to the garden.  If driveways or paths must be crossed, you may need to bury the hose or protect it.
  • Needs of the plants.  They will dictate the sophistication and expense of your system.
  •  The arrangement of your garden — in straight rows or scattered irregularly, tall or short plants, an ornamental display or a working vegetable supply.
  • Finally, don’t forget that central Virginia winters will freeze and sometimes burst hoses left filled outside.

For every system that saves time and effort, nothing replaces a gardener who keeps a watchful eye on the health of the growing things under her care.  The good news is that almost nothing makes more difference in a garden than having enough water.

More information

“Creating A Water-wise Landscape,”

“Environmental Horticulture: Guide to Nutrient Management,” Diane Relf,, (month-by-month management of water and nutrients).

“Filtration, Treatment, and Maintenance Considerations for Micro-Irrigation Systems,” Brian Benham,

“Irrigating the Home Garden,” R. Allen Straw,

“Mulching for a Healthy Landscape,” Diane Relf,

So You Want to Start a Nursery (Tony Avent, Timber Press 2003),  pp. 132-135.

Grasscycling-Let the Clippings Fall

While taking the Master Gardener class, I came to understand that it is actually preferable to leave the grass clippings on the lawn, saving labor and time, but more importantly promoting a healthy lawn.

6 Reasons to practice grasscycling

  • It improves lawn quality when we allow the clippings to decay naturally and provides valuable nutrients.
  • It saves time and work.
  • All lawn mowers can grasscycle.
  • Grass clippings are a free source of slow release fertilizer
  • There is no need to spend tax dollars on landfilling grass.
  • It is a simple, easy opportunity for every homeowner to do something good for the environment.

Are there reasons ever to bag the clippings?

  • If the lawn is heavily diseased, removing clippings may reduce the diseased organism load
  • If the lawn is mowed when wet or excessively long, the clippings will mat together and could damage the lawn under the clumps of clippings.
  • If your mower does not have a method to operate without a bagger.




Asclepias — Or How I Learned to Love Milkweed

While I have strong feelings, pro or con, about most plants, I feel ambivalent about a few.  Asclepias (pronounced ah SKLEE pee us) is one of those, but my attitude toward it has gradually evolved.  As a child growing up on a farm, I knew this plant by its common name — milkweed.  A large, coarse-looking weed, it had little to offer in the way of charm.   It grew aggressively throughout several of the farm’s pasture fields, but the cows and horses avoided it.  I learned early on that if you break the leaves or stems of this plant, a sticky, white sap oozes out and irritates your skin.  The cows and horses, clearly smarter than I was, knew that and left these plants alone.  Once the plant bloomed and set seed, my attitude toward it mellowed a bit.  On the one hand, the spherical clusters of oddly shaped small flowers were interesting to examine.  On the other hand, the flowers were a dull and decidedly unappealing shade of anemic pink.  The monarch butterflies flitting around this plant didn’t seem to mind the color, though.  I guessed, perhaps accurately, that they were attracted to the pleasant scent of the flowers.

In my childlike mind, the only reason milkweed needed to exist was because of its seedpods.  When they matured, they split open, revealing perfectly aligned rows of brown seeds with long, fluffy white hairs attached to them.  As a bored kid with an insatiable curiosity about nature, those seedpods provided me with endless hours of amusement.

Fast forward to adulthood, when I eventually learned about the relationship between milkweed and the life cycle of the monarch butterfly. What an epiphany to discover that the same homely weed about which I felt ambivalent as a child is critical to this beautiful creature’s very existence, specifically at the larval stage.  Looking at milkweed in a whole new light, I set out to learn more about it.  I discovered, for example, that:

  • It is named after the Greek god of medicine, Asklepios.  I can only surmise that this must be a pretty important plant to be given such an auspicious name.
  • Legend has it that this plant has been used throughout history to treat a variety of medical conditions, including pleurisy, arthritis, gall stones, stomach ailments, and even warts.
  • The sticky white sap is mildly poisonous and its bitter taste warns away most animals and insects that attempt to eat it.  Monarch butterfly larvae seem not to be bothered by either the bitter taste or the toxin.  In fact, by feeding on the leaves, they accumulate enough of the toxin in their bodies to make themselves distasteful to predators.
  • During World War II, the buoyant milkweed floss was used as a substitute for kapok in life jackets.

With my new-found knowledge about milkweed, I eventually decided it was time to adjust my attitude about it.   With some (OK, a lot of) reluctance, I added a couple of species to my ornamental garden a few years ago.  I dreaded the idea of incorporating bright orange or other “hot” colors in my garden, which consists predominately of “cool” colors.  Also, there’s something counterintuitive about installing an ornamental plant that is meant to be eaten.   But, you know what? Despite my apprehension, this species has finally grown on me.  Perhaps it took a few monarch butterflies to help me see the light.  Ambivalent no longer, I now find myself hovering anxiously over it in the spring time, waiting for it to break dormancy.  As for the seedpods, I haven’t quite outgrown the desire to play with them, but I’m working on it.

Whether you call it Asclepias or milkweed, the genus consists of more than 100 species of evergreen or deciduous, clump-forming or spreading perennials.  Flora of Virginia lists 15 members of the genus that are native to this state. Of those 15 species, A. tuberosa and A. incarnata tend to be the most commonly grown in the ornamental garden.   Those and a few other selected species are described below.

  • A. syriaca (Common Milkweed).  This is the species that flourished with wild abandon on the farm where I grew up.   It is commonly found throughout much of the eastern United States, particularly along roadsides and in meadows and pastures.  It typically grows about 4 to 5 feet tall and, as mentioned earlier, sports clusters of dull, some might say unappealing, pale pink flowers from late June through July.
    Photo Source: Va. State Arboretum at Blandy

    Asclepias syriaca

    What this plant lacks in color, it makes up for with a distinctive musky scent that butterflies adore. This is not a particularly attractive plant, which is why it’s not ordinarily found growing in orderly, cultivated gardens.  Also, it can aggressively spread by underground rhizomes.


  • A. tuberosa (Butterfly Weed).  This smaller, more refined species grows from 1-1/2 to 3 feet tall and has narrow leaves and clusters of bright orange flowers.  If you’ve ever seen this one growing in the wild, the color fairly jumps out at you (in an attractive way).   Of all the native species, this one appears to be the easiest to find in garden centers and plant catalogs.  A couple of cultivars are available in addition to the orange species:
    • ‘Gay Butterflies’ – This 2 to 3-foot tall plant bears red, orange or yellow flowers.
    • ‘Hello Yellow’
      Photo Credit: Pat Chadwick

      Asclepias tuberosa ‘Hello Yellow’

      — This 2 to 2-1/2 foot tall plant bears bright yellow flowers.  I planted this cultivar a couple of years ago but found the yellow color just a little too vibrant for my tastes.  So I moved it to another spot in the garden where it will blend in better with its neighbors.

  • A. incarnata (Swamp Milkweed).  This thick-stemmed species grows about 3 to 4 feet tall.  The clusters of pink flowers are more colorful than those of its A. syriaca cousin. The flowers have a mild vanilla scent that butterflies go wild over.  This species grows in ditches, swamps, and other moisture-retaining soil.A. incarnata cultivars include:
    • ‘Ice Ballet’ – Slightly smaller than the species at 32 to 40 in. in height, it bears white flowers.
    • ‘Cinderella’ — Growing to about 3 feet tall, it has soft pink flowers that open from deep pink buds. This cultivar can tolerate a dry site.
    • ‘Soulmate— Growing to about 3 feet tall, it has rosy-purple flowers. Like ‘Cinderella’, this cultivar can also tolerate a dry site.
      Photo Credit: Commons.wikimedia

      Asclepias incarnate (Swamp Milkweed)

  • A. purpurascens (Purple Milkweed).
    Photo Credit: Commons.wikimedia

    Asclepias purpurascens (Purple Milkweed)

    This 2 to 3-foot tall species gets its name from the reddish-purple rib on the leaves.  Unfortunately, it is not as commonly available as A. tuberosa or A. incarnata.  As reported by Allan Armitage in his Herbaceous Perennial Plants, this is one of the most attractive members of the genus.  The thick clusters of fragrant flowers start out as dusky pink buds and open to an eye-catching deep rose to reddish-purple color. Although similar in form to its relative A. syriaca, this species is a gentle spreader in the garden.

  • A. variegata (White Milkweed).
    Photo Credit: Ryan Shurette/U.S. Forestry Service

    Asclepias variagata (White Milkweed)

    This species grows from 1 to 4 feet tall with densely arranged clusters of white blossoms having a faint touch of purple at the base of each individual flower.

  • A. verticillata (Whorled Milkweed). This 1 to 3-foot tall species has narrow, whorled leaves and small creamy white flowers along the length of the stems.  One of the most widely distributed of all Asclepias species in the U.S., this selection is one of the few clone-forming species.   Although unlikely to be found in cultivated or grazed landscapes, it does colonize in ditches and along roadsides and is a common late season host plant for monarch larvae.
    Photo Credit: wikimedia.commons

    Asclepias verticillata

In addition to the native species, the following tropical non-natives also support monarch butterfly populations.  Although technically perennials, they are not hardy in Zone 7 and must be grown as annuals.

  • A. Curassavica (Blood Flower or Tropical Milkweed) – This South American native is hardy only to Zone 9.  It grows between 2 and 3 feet tall and produces clusters of yellow and red bi-colored flowers during the latter half of summer into fall.  It will self-sow in most gardens but resents being transplanted.  Readily available through garden centers and on-line sources, it is a favorite nectar source for a wide variety of butterflies, including monarchs.  In the interest of full disclosure, my research revealed some concern about this plant in the southern-most U.S. (Florida and Texas).  Because it stays alive in those warmer climates, the concern is that the monarchs may stick around to feed on it rather than migrate to their usual wintering grounds.  This should not be a problem in Virginia because this plant is not hardy here.  However, if you do grow it and have any concerns about it, cut it back in the fall before it self-sows.
Photo Source: commons.wikimedia

Asclepias curassavica

  • Gomphocarpus physocarpus (Balloon Flower) – Once in a while, I encounter a plant that causes me to stop dead in my tracks in wonder.
    Photo Source: wikimedia

    Gomphocarpus physocarpus (formerly Asclepias physocarpa)

    Such a plant caught my attention at the Green Springs Botanical Garden in northern Virginia about 10 years ago.  The white blossoms on this large, 5-foot tall plant clearly resembled those belonging to members of the Asclepiadaceae genus.  However, it definitely did not resemble any Asclepias species with which I was familiar.   What had me baffled was the pale green, softly spiny-looking clusters of 2 to 2-1/2 inch round, balloon-like seed pods.   Although unusual in appearance, the seedpods were oddly attractive.  Upon researching this plant with its unpronounceable botanical name, I learned that it had been formerly classed as A. physocarpa — a member of the Asclepias family.  It was apparently renamed to indicate its southeast Africa origin.  I never forgot that plant and was delighted to encounter another specimen two years ago in the butterfly garden at the Biltmore estate in North Carolina.   Mature monarch butterflies as well as larvae and pupae liberally covered the plant.  To say that my fellow visitors and I were thoroughly enchanted by both the plant and the cloud of monarchs flitting about it is an understatement!


To provide a source of nectar for adult monarchs and leaves for the larvae, try planting several species of Asclepias, preferably ones that are native to this area.   Don’t limit yourself to just one or two plants.  Plant as many as you can reasonably fit into your garden.

  • Butterfly garden – Incorporate with other nectar-rich plants to attract butterflies and other pollinators.  A few companion plants that come to mind include Joe Pye weed (Eupatorium maculatum), cardinal flower (Lobelia cardinalis), great blue lobelia (Lobelia siphilitica), coneflower (Echinacea), Mexican sunflower (Tithonia rotundifolia), bergamot (Monarda), goldenrod (Solidago), ironweed (Vernonia), and various asters.
  • Meadow or wildflower gardens — This is a particularly suitable application for the larger, coarse-leaved varieties, such as A. syriaca.  Be sure to include other species that bloom later in the season in order to provide a source of food throughout the growing season.
  • Mixed border – Include in a mixed perennial and annual border.  Some varieties, as already noted, have strong colors.  They work best in a border with other “hot” colors, including such plants as tickseed (Coreopsis), black-eyed Susan (Rudbeckia), yarrow (Achillea) and blazing star (Liatris).
  • Decorations – The seedpods can be used in very interesting ways in dried arrangements.  The inner shell of A. syriaca, for example, has a faint silvery sheen that looks particularly attractive when combined with other dried plant materials in holiday wreaths.


Plant Asclepias in average to poor soil that drains very well.  Sandy soil is ideal. Swamp milkweed can tolerate moist soil, as its name suggests, but also grows well in dry soil.  Asclepias prefers full sun but will tolerate partial shade.  Rich soil or heavy shade can cause the stems to be weak or floppy.

Asclepias are among the last of the perennials to emerge in spring.  You might be wise to mark where you plant them or leave the stalks in place over winter so that you don’t lose track of them the following spring.

Handle with care.  The foliage contains latex, a milky substance that may irritate your skin.  If ingested, the plant can be poisonous to both animals and humans.


Asclepias may be propagated by seed, stem cuttings, or root cuttings. For best results with seeds, sow them directly into a bed in autumn or early winter.  The seed of most species needs to be stratified (subjected to a period of cold temperatures) before they sprout in the spring.   Alternatively, seeds may be sown in spring but, to improve the germination rate, stratify them first.  The easiest way to do this is to place them between moist paper towels in a plastic bag and refrigerate them for about 3 to 6 weeks.  Then, remove the seeds from the refrigerator and soak them in warm water for about 24 hours before planting them.  The warm water bath further improves the germination rate.  Tropical species of Asclepias do not require stratification in order to germinate.

To propagate by stem cutting, sever a 3 to 4-inch cutting from a green stem that is about 1/3rd inch thick.  Make the cut ¼ inch below a leaf node.  Remove the lower leaves, dip the cut end of the stem into a rooting compound, and insert the cutting into a container that is filled with moist sand, vermiculite or potting soil. Cover the container with plastic wrap or a glass jar to maintain high humidity until the plant starts to develop roots.  Mist the soil as needed to keep it moist but not soggy.  Cuttings generally require about 6 to 10 weeks to develop good root systems before they can be planted in the garden.

Root cuttings are the trickiest method of propagation for this plant and not generally recommended.  Asclepias has an extensive root system, and if the long tap root is damaged, it may not recover.  If you do attempt this method of propagation, carefully sever a portion of the root system when the plant is dormant.  To root the cutting successfully, make sure it has one or more shoot buds.


Anyone who has ever grown Asclepias knows that it attracts aphids.  These pests, usually orange or yellow in color, cover the stems and leaves of the plant and sap it of its juices.  Ridding the plant of aphids is tricky business because of the risk of harm to monarch butterfly eggs, larvae and pupae.   Here are several strategies for combating these pests:

  • Inspect Asclepias stems and leaves (both sides) daily.  Take immediate action at the first aphid sighting.  Don’t procrastinate.  The sooner you take action, the less of a problem you’ll have over the growing season.
  • Squish the aphids with your fingers, preferably gloved, of course.  Try not to damage the foliage and stems in the process.  A small brush sometimes works well in dislodging aphids, especially from the little nooks and crannies and other tight spots.
  • Carefully direct a spray of water at the aphids to dislodge them.  As you do this, be extremely careful not to spray monarch eggs or larvae. Otherwise, you’ll dislodge them, too.
  • Let natural predators take care of the job.  Lady beetles, lacewings, parasitic wasps, and mantids are natural enemies of aphids.  However, they also eat monarch eggs.
  • For further information on aphids and controls, see VCE Publication 444-220, “Aphids.”  Keep in mind one important fact:  Any controls used for aphids, regardless of how benign, may also affect monarch eggs or larvae.  Proceed carefully with any pest treatment you use.

Milkweed bugs (Oncopeltus fasciatus) are another common pest of the plant.  Unlike aphids, which do a lot of harm, milkweed bugs are more of a nuisance than an actual threat to the plant.  These colorful orange and black insects are usually found in small groups feeding on the seeds, stems and leaves.  The adult insect lives only about a month and doesn’t do much harm to the plant.   The Missouri Botanical Garden website advises simply living with the damage.  Removing leaf litter and spent plant material in the fall helps to control these insects.

Several foliar or fungal diseases, such as powdery mildew, leaf spots and rusts, may affect Asclepias.

  • Powdery mildew may develop on the leaves when there’s a mixture of both damp and dry conditions caused by foggy mornings followed by very dry weather later in the day.  There’s generally not much that can be done or that needs to be done for this problem.
  • Leaf spots are caused by irregular watering or by lack of good air circulation. This is a concern because the diseased leaves are not suitable for monarchs to feed on.  To prevent the problem, avoid overhead watering, especially in the evenings when foliage cannot dry off properly.  Proper spacing of plants is essential for promoting good air circulation.  Remove any affected leaves, particularly those that fall to the ground.
  • Rust stunts the growth of foliage and causes reddish-color spots on leaves.  Carefully remove affected leaves to avoid scattering the fungal spores.


A-Z Encyclopedia of Garden Plants (American Horticulture Society, 2008)

“Aphids,” Va. Coop. Ext. (

Herbaceous Perennial Plants, Third Edition, (Armitage, Allan M., 2008)

Lady Bird Johnson Wild Flower Center, The University of Texas at Austin, (

“Milkweed Bugs,” Missouri Botanical Garden website (Milkweed Bugs)

Monarch Watch (educational outreach program based at University of Kansas, (

“Monarchs and Milkweeds,” National Wildlife Federation website (Pollinators/Monarchs)

Piedmont Virginia Native Plant Database (

“12 Native Milkweeds for Monarchs,” National Wildlife Federation website (12 Native Milkweeds for Monarchs)

United States Department of Agriculture Plant Database (

Virginia Department of Conservation and Recreation, (



The Ornamental Garden in June

With the arrival of the summer solstice on June 20 comes hotter, steamier weather and the most active season of the year for dedicated gardeners.  As spring planting winds down, shift your focus to the following tasks:

Maintain Your Ornamental Beds

  • Weed your flowerbeds at least once a week, more often if you have the time and the inclination.
  • Deadhead spent blossoms on annuals to keep plants looking tidy and to encourage re-blooming.
  • Water plants deeply and infrequently at the root level.  This is particularly important for newly planted ornamentals.  If you use a sprinkler system, try to water in the mornings so that foliage can dry off during the day.

Monitor Ornamentals for Pests and Disease

  • Japanese beetles – The Japanese beetle is one of the most devastating landscape pests in central Virginia at this time of year.  The grubs pupate in the soil in spring and emerge as adults in June and July with voracious appetites.  They arrive in groups and can quickly skeletonize the leaves of many ornamental plants.  The best strategy for managing these beetles is prevention and early detection. When the pests first appear in the landscape, immediately remove them from affected plants.   The logic in doing this is that the presence of the beetles on a plant attracts more beetles.  A quick “organic” way to dispense with them is to pick them off plants by hand early in the morning when they are sluggish and drop them into a bucket of soapy water.  Virginia Cooperative Extension Publication ENTO-97NP, Japanese Beetle, provides information on this pest and strategies for controlling it.  For additional information, see University of Kentucky Cooperative Extension Service Publication ENTFACT-451, Japanese Beetles in the Urban Landscape.  It includes lists of landscape plants that are seldom damaged by Japanese beetles as well as plants that are likely to be attacked by them.


  • Rabbits — It’s easy to blame deer for damage to your ornamentals, but rabbits tend to like the same plants.  Some strategies for keeping bunnies out of your garden include:
    • Deer repellents.  Rabbits and deer belong to the same mammal family and any organic spray that contains rotten eggs and hot pepper should repel both critters.  The downside to repellents is that most of them need to be re-applied after heavy rains.   TIP:   Like deer, rabbits also don’t like the scent of blood meal or Milorganite fertilizer.
    • Fences or other physical barriers. If you have plants that are prone to rabbit browsing, install a physical barrier of chicken wire or other small gauge wire.  If that’s not a practical solution, you may need to consider installing a rabbit-proof fence around your entire garden.  To be effective, the fence needs to be 3 feet tall and constructed of chicken wire or other wire with openings no more than one inch wide.  Rabbits can tunnel, so make sure the bottom of the fence is buried about 6 inches deep.
    • Rabbit-resistant plants.  Rabbits don’t normally bother Allium, Artemisia, Achillea (yarrow), Monarda, Baptisia, Irises, Salvia, lavender, monkshood, Russian sage, lilacs, or viburnums.  For additional rabbit-resistant plantings, check out Penn State’s Cooperative Extension Publication on Rabbit-Resistant Garden and Landscape Plants.
    • Dogs.  If you don’t have a dog, encourage your friends with dogs to visit you often.


Collect and Save Seeds

When you’re not busy battling pests in the garden, try collecting and saving seeds.  Start with spring-blooming plants such as Dianthus, sweet William, poppies, and bleeding hearts. Collect the seeds after the flowers have faded and seeds are dark brown or black.  Spread the seeds out and allow them to dry thoroughly so that they don’t become moldy.  Place the dried seeds in paper envelopes or air-tight glass jars and label and date them.  Store the seeds in a cool, dry, dark place over winter. Some people like to store seeds in their refrigerators.   Remember:  open-pollinated species will come back true from seeds.  Hybrids will not.

Consider yourself to be an advanced seed saver if you try your luck with trickier seeds that require stratification or scarification or both in order to achieve germination.  For example, collect Baptisia seeds after the pods darken and begin to split open.  If you plant the seeds ¼ inch deep while they are fresh, they should germinate within about 2 weeks.   However, if you wait until later in the season to germinate them, they must be chilled (stratified) for 6 to 12 weeks first.  Then, before planting them, scarify them (lightly scratch with sandpaper or nick the seed coat). As an alternative to scarification, pour hot water over the seeds and let them soak for about 24 hours before planting them.

Salvage Root-bound Plants

As prime planting season winds down, you’re likely to encounter lots of “bargain” plants for sale.  Make sure you’re buying healthy specimens and not badly stressed plants.  I’m referring specifically to root-bound plants that have outgrown their pots and not been re-potted into larger containers.  Being root-bound (or pot-bound) prevents plants from taking up water and nutrients, stunts the plant’s growth, and may eventually kill it.  Root-bound plants are easy to spot.  They’re the ones with roots growing out of the pot’s drainage holes. If you want to try salvaging such a plant, cut off the roots that have emerged through the drainage holes and remove the plant from the container.  You’ll see dense masses of matted and tangled roots.  In some cases, the roots may be coiled in a circle at the bottom of the pot.  If the roots are brown or black, they are probably dead.  If they are white, they are alive.  Cut off any extremely long coiled roots near the root ball.  Using a sharp knife or hand pruners, make several vertical cuts through the root ball about 1 to 2 inches deep (depending on the size of the root ball).   While that sounds drastic, it’s necessary in order to stimulate new root growth.  It help the roots grow out or down into the soil rather than around in a circle.

Divide daffodils

After daffodil foliage has died back, use a shovel or garden spade to dig up the bulbs.  Dig several inches away from the clump to avoid damaging the bulbs and their offsets.   Bulbs are usually planted fairly deep, so be prepared to dig down to about the depth of your spade.  Lift the clump of bulbs from the ground being careful not to damage the roots.  Gently twist the bulbs apart with your fingers.  Discard any that look damaged or diseased.  Re-plant the bulbs in a sunny spot with good drainage.  Mix in a good amount of compost or other organic matter before you replant them.  Plant them three times deeper than the circumference of the bulb.  In other words, if the bulb measures two inches around its middle, plant it six inches deep.   If you replant any of the bulbs in the original location, incorporate some fertilizer in the planting site to re-build nutrient levels.

Propagate Stem Cuttings

Late spring to early summer is a good time to propagate stem cuttings of woody ornamental plants.  Camellia, cotoneaster, viburnum, deutzia, and lilac are examples of plants that can be easily propagated this way. Softwood cuttings should be taken from tender new growth on woody plants, just as it begins to harden.  To learn how to propagate plants, refer to Virginia Cooperative Extension’s publication 426-002 on Propagation by Cuttings, Layering and Division (

Remove Spent Rhododendron Blooms

Now that rhododendrons have finished blooming, carefully remove the old blooms.  This will promote better blooming next year.  In addition, it will give the plant a tidier appearance and will help prevent insect infestations.  The best time to deadhead is within 2 to 3 weeks after the blooms have faded.  The technique for deadheading is simple:  Grasp the spent blossom cluster (called a truss) and carefully pinch it off or push it aside with your thumb.  This will reveal the developing flower buds for next year’s flowers.   Be careful not to injure those as you remove this year’s dead flower clusters.

Plant Succulents

If you’re looking for something different for your garden, try growing succulents.   Many species of Sedum, Sempervivum, and Euphorbia can tolerate our summer humidity and are hardy enough to withstand our USDA Zone 7 winters.  Sedums, in particular, are drought tolerant once established, deer resistant, and may be used as an alternative to mulch for smothering weeds.  They are low- growing, colorful, and, in some cases, finely textured.   A few that are readily available in garden centers include ‘John Creech’, ‘Blue Carpet’, ‘Angelina’, ‘Lime Zinger’, and ‘Dragon’s Blood’.  Give them a sunny spot and plant them in well-drained soil.   Most Sedums are slow growing but a few are aggressive growers. Fortunately, they are easy to pull out.  Just don’t let them crawl over into your lawn where they may be more difficult to remove.

Soil that drains well, especially in the winter, is key to growing succulents successfully.  To improve drainage, mix some pea gravel or horticultural grit (which is smaller than pea gravel but coarser than sand) into the soil.  You may also need to build up or mound the soil so that water flows away from the plants.  If you select succulents that are not hardy enough for our winter weather, try growing them in containers in soil that has been formulated for cacti and succulents and then bring the containers indoors for winter.

Consider Designing and Installing a Rain Garden

More and more people are installing rain gardens to capture rainfall and storm-water runoff.  If you’re in the process of planning a rain garden, choose plants for it that can tolerate occasional flooding as well as long periods of dry weather.  Va. Coop. Ext. Publication 426-043 on Rain Garden Plants recommends one plant species for every 10 to 20 square feet.  In the example they give, a 140-square-foot garden should have 7 to 14 different plant species, consisting of a mix of tall, medium and low-growing species.  A sampling of some of the plants recommended for rain gardens include:

  • Trees:  Black gum (Nyssa sylvatica), Carolina silverbell (Halesia tetraptera) and hornbeam (Carpinus caroliniana)
  • Shrubs:  American beautyberry (Callicarpa Americana), spicebush (Lindera benzoin), and winterberry (Ilex verticillata)
  • Perennials:  Beard tongue (Penstemon), black-eyed Susan (Rudbeckia), and blue lobelia (Lobelia siphilitica)
  • Ferns:  Cinnamon Fern (Osmunda cinnamomea), holly fern (Crytomium falcatum), and royal fern (Osmunda regalis)
  • Grasses:  Feather reed grass (Calamagrostis acutiflora), switchgrass (Panicum virgatum), and foxtail grass (Alopecurus pratensis)

Eradicate Poison Ivy

Are you familiar with the rhyme “Leaves of three, leave them be?”  The reference is to poison ivy.  On average, it takes about 2 to 3 weeks to recover from the rash caused by contact with urushiol (pronounced u-ROO-she-ol), the active ingredient in the plant’s sap.  If you find this noxious vine sprouting in your landscape, here’s how to get rid of it safely:  Loosen the soil around the roots so that they will be easier to pull.   Slip a plastic trash bag over your gloved hand.  Grasp the plant through the plastic bag and pull it out by its roots.  Pull the trash bag up over the plant, securely tie the bag, and place it in the trash.  DO NOT COMPOST OR BURN THIS PLANT.













Pasta Primavera with Asparagus and Peas



Who doesn’t love pasta? It has long been a favorite of people of all ages the world over—delicious, economical, filling, and open to endless possibilities. Pasta’s infinite varieties can be dressed in many different ways.

Cookbooks are rife with recipes for pasta primavera, pasta combined with lightly cooked vegetables. According to Wikipedia, its exact origins are disputed, but all agree that pasta primavera first appeared on restaurant menus in the 1970’s in Manhattan. Many recipes for this healthy dish include a chorus of vegetables—broccoli, red pepper, zucchini, mushrooms, etc.—but I love the simplicity of the following recipe from Melissa Clark, highlighting crisp asparagus and peas.

This recipe calls for fresh pasta. I do think it makes a difference. I used fettuccine, cooked for about 2 ½ minutes only, from Mona Lisa Pasta in Charlottesville.


Ingredients (for four)

¼ pound sugar snap peas, stems trimmed

½ pound asparagus, ends snapped

2 tablespoons unsalted butter

¾ cup fresh English peas

¼ cup thinly sliced spring onion, white part only (or use shallot)

2 garlic cloves, finely chopped

½ teaspoon fine sea salt, more as needed

Black pepper, more as needed

12 ounces fettuccine or tagliatelle, preferably fresh

⅔ cup grated Parmigiano-Reggiano, at room temperature

½ cup crème fraîche or whole milk Greek yogurt, at room temperature

3 tablespoons finely chopped parsley

1 tablespoon finely chopped tarragon



  • Bring a large pot of heavily salted water to a boil over medium-high heat.
  • While the water is coming to a boil, slice snap peas and asparagus stems into 1/4-inch-thick pieces; leave asparagus tips whole.
  • Melt butter in a large skillet over medium-high heat. Add snap peas, asparagus, English peas and onion. Cook until vegetables are barely tender (but not too soft or mushy), 3 to 4 minutes. Stir in garlic and cook 1 minute more. Season with salt and pepper; set aside.
  • Drop pasta into boiling water and cook until al dente (1 to 3 minutes for fresh pasta, more for dried pasta). Drain well and transfer pasta to a large bowl. Immediately toss pasta with vegetables, Parmigiano-Reggiano, crème fraîche and herbs. Season generously with salt and pepper, if needed.



One of the beauties of finding recipes online is the opportunity to read comments from those who have tried the recipes. Thus, cooking becomes a more interactive experience. I found the following suggestions useful:

  • Rather than the crème fraîche, drizzle olive oil over the finished product—more natural and lighter. (I tried it both ways. Personal preference reigns. Both are delicious.)
  • Add frozen peas after draining the pasta; then toss. (I agree. This keeps the peas tasty and crisp.)