The Ornamental Garden in June
My husband and I went away for a couple of weeks in May, and when we returned our landscape looked overwhelmingly “verdant.” Some of the perennials, such as peonies, had come and gone; the weeds were on steroids; deer had bedded down on our old-fashioned bleeding hearts (Dicentra spectibilis); flowers needed deadheading. I felt a little out of sorts about having gone away at the height of the garden growth spurt. When I put my garden gloves back on, I reminded myself that there were life lessons to learn from facing a somewhat neglected June garden.
- Focus on the positive. (Not on the yellowing stalks of spring blooms)
- Let go of the past and be present in the moment. (The perennial bloom calendar, including peonies, goes marching on)
- Success is the sum of small efforts, repeated day in and day out. (Weeding)
- There is simply no substitute for hard work when it comes to achieving success. (Deadheading)
- Beauty is as beauty does. (Planting milkweed in the perennial garden)
- By failing to prepare, you are preparing to fail. (Composting and mulching)
- Happiness is not something you postpone for the future; it is something you design for the present. (Adding annuals for color in the perennial garden)
There are a lot of tasks in June that can keep the garden looking fresh and the plants happy.
Weeds seem to love hot weather. Adding another light layer of mulch can help keep down the weeds and maintain moisture in the soil which makes weed pulling easier. At this point in the season, more frequently-worked garden spots might need some additional mulch.
Daffodils, tulips, and other spring bulbs need to store food through their foliage. Daffodils continue to absorb nutrients for about six weeks after the blooms have died. You can either let them die back naturally, or cut them back after they’ve turned yellow. Do not tie or bind the foliage.
June often brings drier weather which means we need to water newly-planted plants, container plants, and any established plants that look wilted after even a short dry period. In times of drought, water infrequently and deeply, about 1” per week. For more info, see The Garden Shed June 2016 article, “Growing Things When the Rains Don’t Come.”
As soon as plants are allowed to set seed, chemical messages are sent back telling flower production to stop. Deadheading spent blooms short-circuits this message so that flowering will continue. Trimming off yellowing foliage also keeps the garden looking fresh when leaves are spent or have been damaged by slugs or insects.
When you pinch a plant with your thumb and forefinger, you remove the main stem, forcing the plant to grow two new stems from the leaf nodes below the pinch. You may remove just the new emerging leaves or down several inches to a side bud. Some plants, but not all, benefit from being pinched back to promote a bushier growth. Chrysanthemums and asters are two fall-blooming plants that especially benefit. Both plants can be pinched several times by July 4th. Stop pinching by this date or soon after so that you don’t interfere with bud production. Pinching back herbs, such as basil, helps the plants to produce more of their desirable leaves and keeps them from getting too leggy.
As the season progresses, some taller plants or top-heavy plants benefit from staking. If plants fall over, the stem will function poorly where it has been bent. If the stem is cracked, disease organisms can penetrate the break. Stake plants when you set them out so they will grow to cover the stakes. When staked, tall perennials can better withstand hard, driving rain, and wind. Select stakes that will be 6”–12” inches shorter than the height of the grown plant.
Many bushes should be pruned in June. Spring or early summer blooming shrubs such as azaleas, forsythia, lilac, deciduous viburnums, rhododendrons, and spring-blooming hydrangeas should be pruned after blooming but before new buds are set. Please see the shrub pruning schedule published by the Virginia Cooperative Extension.
The challenge and reward of creating a beautiful perennial garden is to create combinations of complementary colors and textures that roll through the season. Is it “cheating” to add annuals? Annuals are an asset that should be used! Lantana (L. camara, upright, and L. montevidensis, trailing) offers vibrant colors; globe amaranth (Gomphrena globosa) adds a huge pop of magenta; verbena (Verbena x hybrid), salvia, floss flower (Ageratum houstonianum), angelonia (Angelonia angustifolia), and so many others, add beautiful, ongoing color to the garden. See the June 2018 issue of The Garden Shed for additional information.
MORE TASKS AND TIPS
Lace bug damage is evidenced by yellow spots on the upper sides of the leaves. When feeding damage becomes severe, the leaves take on a gray, blotched appearance or can turn completely brown. As lace bugs feed, they produce brown varnishlike droppings that spot the underside of the leaves. When large numbers of lace bugs are present, cast skins can be found attached to the leaves. Lace bugs feed on the undersides of leaves with their piercing-sucking mouthparts, so check the underside of leaves for adults, nymphs, and small, black, smoke-stack-looking eggs. Adult lace bugs are about 1/8” – 1/4″ long with a netlike pattern on the wings. Nymphs are similar in appearance to the adults but are smaller and often have spines. Recognition of the host plant is helpful in identifying lace bugs because these insects are highly host specific (feed only on one plant or a closely-related species).
Azalea lacebug ( Stephanitis pyrioides ): Two generations of azalea lace bugs occur in Virginia per year. Try to control the first generation from mid-May to mid-June; two sprays may be necessary. The second brood builds up to high populations in August and September, and damage can be severe on azaleas that are planted in full sun. In some cases, the leaves turn completely brown and are heavily spotted with droppings by the end of the summer. The azalea lace bug was accidentally introduced from Japan.
Rhododendron Lace Bug (S. rhododendri): Treat in May or June to control the first generation. Rhododendrons growing in full sun may have a yellowish appearance from feeding by rhododendron lace bugs. The rhododendron lace bug is native.
Sycamore Lace Bug (Corythucha ciliata): Native to North America, insect damage is evidenced by a white stippling of the leaves that can eventually progress into chlorotic or bronzed foliage and premature senescence (aging) of leaves. In cases of severe infestations, trees may be defoliated in late summer. Heavy infestations are more common in urban areas than in natural settings. Damage is more severe during dry weather.
Lace Bug Control: Lace bug control requires careful monitoring early in the season. Control should be applied when insects are found on the foliage, either on adults on deciduous plants or on groups of nymphs on broad-leaved evergreens. It is very important to spray the undersides of the leaves because this is where they feed. A repeat application in 10 to 14 days will sometimes eliminate the need to control the next generation. For more information on cultural practices that deter pest damage, natural enemies of pests, and chemical solutions for serious infestations, see “Ask An Expert.”
Roses are a favorite of many gardeners, and unfortunately, to many insect pests as well! Inspect roses for aphids, mites, and thrips. Frequent inspections increase the likelihood that a pest infestation will be detected early, when pest numbers are low and control is easiest.
Control: Pests can be hosed off with a strong stream of water directed above and below the leaves. Spraying with water should be repeated frequently as needed, focusing in particular on new growth. For information on pest identification, natural enemies, and chemical solutions for more serious infestations, see Rose Insects & Related Pests.
INVASIVE SPOTLIGHT: WAVYLEAF GRASS OR WAVYLEAF BASKETGRASS
Japanese stiltgrass (Microstegium vimineum), an invasive plant common to our area, was highlighted in the June 2018 issue of The Garden Shed. This month’s invasive spotlight is on wavyleaf grass or wavyleaf basketgrass (Oplismenus undulatifoius), an invasive plant commonly found with Japanese stiltgrass. Wavyleaf was first discovered in the U.S. in Maryland in 1996; as of 2017, wavyleaf is known to be in fifteen Virginia counties, including Albemarle.
Wavyleaf’s rapid growth and dense roots and foliage have the potential to smother wildflowers, ferns, and other ground-layer plants, and to prevent forest tree and shrub regeneration. Invasions of this grass deplete food sources for mammals, birds, and insects and spell the destruction of our forests.
Although similar to each other in appearance, Japanese stiltgrass flourishes in both sun and shade, while wavyleaf grows only in shaded areas. Wavygrass leaves are rippled across their width and end with an elongated sharp tip. The leaf bases touch the stems but do not clasp or wrap around them, an important identifying characteristic. The stems are noticeably covered with short, white hairs.
Wavyleaf grass is a perennial, which gives it a decided advantage over invasive annuals such as Japanese stiltgrass. Wavyleaf emerges from dormancy and starts growing rapidly in April. It has ground-hugging, root-like stems, called stolons, which creep beneath leaf litter on the forest floor. Seeds germinate from April into June. Spikes of white flowers rise above the plants from August to November. The sticky seeds are produced first at the bottom of the spikes while new flowers bloom near the top.
Wavyleaf seeds hitchhike for miles by gluing themselves to animal fur and clothing. The sticky, difficult-to-remove seeds can remain attached for days or even months. Deer are one of the primary seed movers, as well as bears, other wildlife, hikers, hunters and pets.
Wavyleaf can be hand-pulled if populations are small, but all bits and pieces of stolons must be removed or they will re-sprout. Be sure to remove tiny seedlings, which resemble miniature, mature plants. Hand-pulling is ineffective in large areas of infestation.
Foliar Spray: Use a recommended grass-specific herbicide from April through June. This won’t harm wildflowers and is approved for wildlife management areas. Do not use a grass-specific herbicide in a wetland or near a stream, because of potential harm to fish and aquatics According to one study, grass-specific herbicides are less effective on wavyleaf in summer. After June, use a non-selective herbicide; this may also be used from April until frost.
NOTE: For currently approved herbicide recommendations, check the Virginia Department of Forestry chart, Non-Native Invasive Plant Species Control Treatments, which you can download from the Blue Ridge PRISM website
If you think you’ve found wavyleaf, take a photo and a GPS location. Report findings to Kevin Heffernan at the Virginia Department of Conservation & Recreation. Contact: 804-786-9112 or email@example.com.
“Daffodil FAQs,” The American Daffodil Society, https://daffodilusa.org/daffodil-info/daffodil-faqs/
“Garden Calendar,” The Morton Arboretum, https://www.mortonarb.org/trees-plants/tree-and-plant-advice/horticulture-care/garden-calendar
“A Guide to Successful Pruning, Shrub Pruning Calendar,” Virginia Cooperative Extension, https://www.pubs.ext.vt.edu/430/430-462/430-462.html
“Pinching and Pruning – A Perennial Primer,” University of Illinois Extension, https://web.extension.illinois.edu/cfiv/homeowners/060427.html
“Lace Bugs – Hemptera: Tingidae,” VCE, https://www.pubs.ext.vt.edu/3104/3104-1581/3104-1581.html
“Lace Bugs on Broad-Leaved Evergreen Ornamentals,” Penn State Insect Advice from Extension, https://ento.psu.edu/extension/factsheets/lace-bugs-evergreens
“Treatment for Lace Bugs on Azaleas and Rhododendrons,” Cooperative Extension, https://ask.extension.org/questions/304777
“Featured Creatures: Sycamore Lace Bug,” University of Florida, https://entnemdept.ifas.ufl.edu/creatures/trees/sycamore_lace_bug.htm
“Rose Insects & Related Pests,” Clemson Cooperative Extension, https://hgic.clemson.edu/factsheet/rose-insects-related-pests/
Wavyleaf Basketgrass, University of Maryland Extension, https://extension.umd.edu/hgic/topics/wavyleaf-basketgrass
New York Invasive Species Information, http://nyis.info/non-native-plant-assessments/
Report All Sightings of this Dangerous, Dreaded Invasive Wavyleaf Grass or Wavyleaf Basketgrass, https://blueridgeprism.org/factsheets/