Timing is critical to keeping your ornamental garden looking interesting, particularly during the hot summer months. The garden is in full bloom now in June but think ahead to what the late summer or fall garden will look like. Although planting season is basically over, it’s not too late to plant annuals and perennials that will provide plenty of color up until frost.
Routine gardening chores this month
By now, we’re largely done with our spring chores, such as bed preparation, seeding, dividing, transplanting, and mulching. It’s now time to switch to maintenance mode to keep the garden looking fresh and inviting. Some routine maintenance tasks include:
Deadheading — As annuals become established, deadhead spent flowers to encourage the plant to produce another round of flowers. A few minutes spent deadheading each week will keep those annuals blooming well into the growing season. TIP: Many of the newer varieties of annuals are self-cleaning and don’t need to be deadheaded.
Pinching – The objective of pinching back annuals, such as petunias and coleus, is to keep the plants bushy and prevent them from becoming leggy. Pinch back the stem to just above a leaf node.
Propagating – Late spring to early summer is a good time to propagate stem cuttings of woody ornamental plants such as camellia, cotoneaster, viburnum, deutzia, and lilac. Take softwood cuttings from tender new growth on woody plants, just as it begins to harden. To learn more about propagating plants, refer to Virginia Cooperative Extension (VCE) publication 426-002 on Propagation by Cuttings, Layering and Division.
Staking – Install supports for plants that tend to collapse or flop over. Stake taller plants, such as foxglove, yarrow, and delphiniums, and cage mounding plants, such as peonies or chrysanthemums. This is particularly critical if your garden is in a windy site.
Weeding – With the onset of warmer weather, stay on top of the weeds in your flowerbed. Pull weeds at least once a week or more often if you have the time and the inclination. For help with identifying weeds, try Weed Identification Photos/Maryland Ext
Watering – Water trees and shrubs deeply and infrequently at the root level to help them get through the summer heat. This is particularly important during the first few growing seasons after a tree or shrub is planted. It’s also important for all plantings during drought conditions. If you use a sprinkler system for your annuals and perennials, water them in the mornings so that foliage can dry off during the day.
For containerized plants, keep close tabs on their water requirements. This is particularly critical if you’re planning to go away on vacation. Group containerized plants together near a hose or other water source so that it will be easier for your neighbor or other helpful person to water your plants for you in your absence. Place the plants where they will be out of the afternoon sun. This will help them conserve water.
Collecting and saving seeds – Given the rising costs of seeds these days, collecting and saving your own is both rewarding and economical. Collect seeds after 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. Important: While open-pollinated species will come back true from seeds, hybrids will not.
Dividing 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. 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 as deep in the soil as the circumference of the bulb. In other words, if the bulb measures two inches around its middle, plant it six inches deep.
Removing spent rhododendron blooms – Now that rhododendrons have finished blooming, carefully remove the old blooms within 2 to 3 weeks after they have faded. This will promote better blooming next year, give the plant a tidier appearance, and help prevent insect infestations. The technique 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.
Monitoring plants for signs of powdery mildew – Garden Phlox (Phlox paniculata) is one of the classic mainstays of the sunny perennial border. But powdery mildew can devastate the foliage of this native plant and turn it into an ugly, unsightly mess. To combat this disease, plant garden phlox in full sun. Space the plants about 18 to 24 inches apart to allow for good air circulation. Thin out established clumps by snipping out the weakest stems, leaving only 5 or 6 sturdy stems. Water well, particularly during dry weather, with a soaker hose at soil level and avoid wetting the foliage. Mulch around the roots to help retain moisture in the soil.
Training vines, climbing roses, and other twining or climbing plants. Vining plants normally go through a growth spurt in early summer. As they grow, train them onto supports before they become unmanageable. As you tie them up, spread them out to the extent possible to cover trellises better and to provide better air circulation.
Monitoring houseplants to keep them from sprawling. The move outdoors into brighter light and fresh air provides just the jump start that many houseplants need for a growth spurt. Jade plant is an example of a houseplant that tends to sprawl. To keep it under control, pinch off the side shoots to keep the plant growing upright. Don’t toss the side shoots that you pinched off. Pot them and start new plants.
Gardening Projects To Consider
Considering designing and installing a Rain Garden? A rain garden is an environmentally responsible way to capture rainfall and storm-water runoff. If you’re in the process of planning one, choose plants that can tolerate both occasional flooding and long periods of dry weather. VCE Publication 426-043 on Rain Garden Plants recommends one plant species for every 10 to 20 square feet. In the example given, a 140-square-foot garden should have 7 to 14 different plant species consisting of a mix of tall, medium and low growing species. Some 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)
Thinking about creating a butterfly garden? If so, check out Virginia Tech’s publication HORT-59NP, Creating Inviting Habitats for Birds, Butterflies, and Hummingbirds. You’ll find guidance on which host plants to grow, depending on the life cycle of the butterfly. Adult butterflies require nectar, whereas caterpillars require leaves or other plant parts. Native plant species support more butterfly and moth species than introduced plants. Incorporate a wide range of plants that bloom throughout the growing season. Also, group plants of the same species together to form a mass of color or fragrance. A mass planting makes it easier for pollinators to spot your garden and encourages them to swoop in for a closer inspection. If they like what they see, they’ll happily make your garden a regular stop on their daily food-foraging expeditions.
Pests, Wildlife, and Other Aggravations
Japanese beetles – The grubs of this devastating landscape pest pupate in the soil in spring and emerge as adults in June and July with voracious appetites. The best strategy for managing these beetles is prevention and early detection. When they 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. VCE Publication ENTO-97NP, Japanese Beetle, provides information on this pest and strategies for controlling it. University of Kentucky Cooperative Extension Service Publication ENTFACT-451, Japanese Beetles in the Urban Landscape includes lists of landscape plants that are seldom damaged by Japanese beetles as well as plants that are likely to be attacked by them.
Mosquitos — As the weather grows warmer this month, mosquitos make their appearance on the scene. It only takes a tablespoon or so of standing water to provide a potential breeding place for mosquitos. Monitor all potential mosquito breeding places such as birdbaths, drainpipes, or saucers under potted plants and remove standing water immediately.
Rabbits – Our first impulse is to blame deer for damage to our gardens, but rabbits tend to like the same plants. Organic deer repellent sprays containing rotten eggs and hot pepper should repel both animals. The downside to repellents is that most of them need to be re-applied after heavy rains. A better solution is to install a 3-foot tall physical barrier constructed of chicken wire or other small gauge wire with openings no more than one inch wide. Rabbits can tunnel, so bury the bottom of the fence about 6 inches deep into the soil. If it’s not possible to install a physical barrier, then use plants that are rabbit resistant. Penn State’s Cooperative Extension offers some suggestions in its publication on Rabbit-Resistant Garden and Landscape plants.
Poison Ivy – “Leaves of three, leave them be” is an easy way to help you identify poison ivy. It takes about 2 to 3 weeks on average to recover from the itchy rash caused by contact with urushiol (pronounced u-ROO-she-ol), the active ingredient in the plant’s sap. To remove this vine safely from your landscape, 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, 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. If, however, you are one of those lucky people not bothered by poison ivy, then consider leaving it alone. The berries are an important food source for many of our birds. In fact, a Pennsylvania State University source suggests that more than 60 bird species consume poison ivy berries.
Invasive Alert: Mile-a-minute vine (Persicaria perfoliata, formerly Polygonum perfoliatum) gets its common name from its ability to grow 6” a day and 25’ in a single season. Tiny, sharp, recurved barbs line the veins on the backs of the leaves and on the stems, which inspired its other common name of Tearthumb. This invasive annual vine forms dense mats of foliage and scrambles over other plants blocking out light and killing them. Tiny white flowers begin blooming in June, followed by showy bright blue fruits that are dispersed by birds and by waterways (because the fruits float). The plant produces flowers and fruits continually from early summer until frost. Shallow roots make the plant easy to pull up, but the recurved barbs can easily pierce skin. So be sure to wear protective gardening gloves when manually pulling this vine. Both manual pulling and herbicide treatments should be done before seed setting in mid to late June. For large, infested areas, apply preemergent herbicides to the soil in early to mid-March.
For information on other invasive species to watch out for in June, see the Invasive Plant Control Calendar in the May 2022 issue of The Garden Shed.
SOURCES:
Featured Photo: Butterfly weed (Asclepias tuberosa) by Pat Chadwick
Monthly Gardening Tips/June, Piedmont Master Gardeners/Gardening Resources
The Well-Tended Perennial Garden: Planting & Pruning Techniques (Tracy DiSabato-Aust, 2006)
Thanks, Pat– always good to be reminded/educated!