As stay-at-home gardeners cope with another scorching Washington summer, the landscape abruptly shifts from problems to opportunities. For the next four-plus weeks, summer gardening will be what you want it to be. Spring projects that were impossible even for advanced gardeners are now transformed into foolproof adventures for novice gardeners. Houseplant fanciers who have patiently waited on the sidelines until now will want to start propagating new plants by stem and tip cuttings. You may not have a choice about summering at home this year, but you do have a choice as to how the landscape will profit from your leisure activities.
Here are a few summertime projects to consider:
If you take gardening seriously, this is the one time of year to take softwood cuttings from shrubs. Plants from which cuttings may be taken include arborvitae, Andromeda (pieris japonica), azalea, boxwood, buddleia (butterfly bush), burning bush (euonymus), camellia, cotoneaster, dogwood, firethorn, forsythia, holly, honeysuckle, hydrangea, inkberry, juniper, kerria, laurel, leucothoe, ligustrum (privet), lilac, mahonia (barberry), nandina, photinia, pyracantha, Rose of Sharon (hibiscus), spirea, styrax, taxus (yew), viburnum, vitex and weigela.
If you have room indoors, it's best to root cuttings there, otherwise cuttings should go outdoors.
Take stem-tip cuttings (from ends of healthy branches) about six inches long. Immediately immerse cuttings in a container of water. Label each cutting with masking tape; otherwise, root cuttings from each shrub in individual plastic pots. The bigger the pot, the more cuttings you can root.
Fill pots with pre-wet 1-1-1, meaning equal amounts of sphagnum peat moss (either "milled" or compressed), perlite and vermiculite. Usually, this mix has a soil pH below 4, therefore you'll need to add pulverized lime to raise the pH above 6 in most cases. Remove all foliage on the bottom half of each cutting, then scarify the stem with a sharp kitchen knife to bare some of the outer tissue.
Using the eraser end of a pencil, poke three-inch holes in the pots, spacing them two inches apart. Add hormone powder (Hormodin #2 or Rootone) to a saucer, roll the bare stem of each cutting in the powder, then stand the cutting in the pre-drilled hole. Holding the cutting with one hand, grip a kitchen knife with the other. Insert it three inches into the soil, then use the flat blade of the knife to move soil next to the stem. Repeat this on all sides so soil contacts the stem. Fill the pot with as many cuttings as you want, making sure that you label the pot in some way to identify cuttings. Spray-mist warm water over the soil, then move each pot into its own clear plastic bag to serve as an artificial greenhouse for rooting cuttings. Gather each at the top, blow into the bag to inflate it, then twist the bag at the top and seal with a rubber band.
Cuttings need warm air temperatures and no sunlight whatever to root quickly. Keeping pots indoors in air-conditioned rooms is self-defeating, therefore consider moving potted cuttings "outdoors" to a screened-in porch, garage, carport or similar facility; no direct sun should strike the cuttings at any time of day. Every five days, open the plastic bag, spray-mist warm water over the soil, then return the bag in place and inflate once more. Post a schedule indoors so you know when to spray-mist the next time. In warm temperatures, cuttings will root in three weeks. The July 21 column will finish the scenario for these shrub cuttings.
Readers with shady gardens also enjoy the option of rooting cuttings outdoors; at no time should sun strike the cuttings. Dig a V-shaped trench to accommodate as many cuttings as you want to plant, making the trench "high" at one end and "low" at the other for drainage purposes. Thrust the spade its full length in the trench when you dig. Put down a three-inch layer of sharp sand (builder's sand from the hardware store) the entire length of the trench for improved drainage.
Prepare your cuttings the same way as before, then stand your cuttings on the back wall of the V-trench, keeping them six inches apart. Backfill the trench with an equal mix of sharp sand and leafmold; lacking this compost, use Michigan peat or peat humus instead. Add some pulverized lime and acrylic copolymers to the soil, too, after which you sprinkle warm water over the trench to remove air pockets. Next, use your electronic pH soil tester to check the pH; try for a pH of about 6. Mulch with a two-inch layer of pine bark nuggets or salt hay. Water the trench daily if there is no rain. Cuttings will remain in place until next spring, but forsythia may be moved in late September if needed.
Set up Japanese beetle traps now if you haven't done so already. Beetles are now starting their summer-long mating cycle in which females burrow overnight into the soil of a sunny lawn to deposit two or three eggs, then are airborne the next day to commence another feeding and mating cycle. Today's beetle traps really work if you locate them properly.
Now is the best time of year to launch a neighborhood effort to have "milky spore" applied to all sunny lawns. One application now to all neighboring lawns will eliminate Japanese beetles for the next 15-plus years. Contractors are equipped to handle the entire project, with charges per home averaging below $100.
In the absence of beetle traps or a milky spore treatment, you can expect to have grubworm damage on sunny lawns by the last week of July. Meanwhile, check for special sales on granular insecticides, such as Diazinon and Dursban. Liquid products should be avoided since they are quickly bound up in the thatch, and will not be washed into the soil to control grubs. Time this application for the last weekend of July.
In our rush to plant annuals and perennials in May, many of us are plant by habit and not with purpose. Correct these mistakes while there is still time. As you walk your garden this weekend, seek out areas that have been neglected until now, then do something about it.
What to plant? Forget that which you've grown for years. Instead, discover some seldom seen perennials that will take visitors' breaths away: monarda, lythrum, baltonia and rosemallow. If your plant discoveries this year are limited to these, you will have won the landscape lottery.
Monarda is also known as bee balm and bergamot. This mint-aroma perennial attracts hummingbirds and butterflies as few plants do. Set in full or partial sun about a foot apart, monarda deserves well-drained soil, therefore pour a few inches of sharp sand at the base of the hole before planting. Work acrylic copolymers into the soil as you plant, too. Mulch to conserve summer moisture in the soil. Summertime rewards you with lacy flowers on stems three to four feet tall, and flowers continue into September. The blossoms are pink, red, ruby, violet, lilac, purple, lavender, mauve and scarlet, so choose your monarda carefully. Divide the clumps every four years.
If there is an absolutely perfect perennial, lythrum is the hands-down choice. Its virtues make it the "who's who" of bedding plants: it is heat- and drought-resistant; it doesn't produce seed, therefore it won't invade other parts of the garden; it is foolproof to grow; it produces profuse flowers from June past Labor Day; and it is immune to disease and not troubled by insects. Apart from these assets, lythrum yields spike-like flowers from deep pink to purple on stalks three to four feet tall. Set plants 18 to 24 inches apart, but make sure you work a handful or two of sharp sand into the hole before planting to provide near-perfect drainage. Work peat humus, acrylic copolymers and sharp sand into the hole as you plant, mulching afterward to conserve moisture.
Baltonia is one of the landscape's most underrated perennials. Planted in full sun or light shade, it grows quickly to heights of three to six feet, making it a perfect choice for background planting. Flowers are of the white daisy type, showing abundantly from mid-July past Labor Day. Some dwarf plants have come on the market recently, with these growing to heights of about 30 inches.
Neighbors have their sunflowers, but you could enjoy rosemallow with its five- to nine-inch summer flowers of deep crimson and pink borders, always with white centers. The plant is a variety of hibiscus, meaning that it self-seeds every year; seedlings sprouting in the summer should be transplanted the following spring. The plant thrives in moist soil, so work acrylic copolymers into the peat humus when you plant.
Jack Eden is the host of "Over the Garden Fence" Sundays from 10 a.m. to 1 p.m. on WTOP Radio (1500 AM).