Another productive thing you can do for your gardens this summer is sow more seed, not only for fall harvest of vegetables, but also sow seeds for ornamental perennials. This is a good time to do it so that these new plants have a chance to settle into your soil and watering regimen before winter arrives. Then in spring, they’ll reappear to enrich your flower beds with low-cost new plants. I think the best idea is to watch perennials to see when they set their seeds, and when those seeds turn brown to black. If they’re white or green they might sprout, but seedlings will be weak.
Seeds are relatively inexpensive, although they used to be a lot cheaper. I’d start with seeds for a reliable perennial such as Shasta daisy, rudbeckia or coneflowers, all of which can do double duty as cut flowers for indoor enjoyment. It may take three to five weeks for seeds to germinate. If they have not germinated by then, put them in a container with potting soil and into a refrigerator for a week, then put out again. Some planting instructions that tell you to put seeds through a chill before planting don’t mention that chilling period should be in damp potting soil, either in a container or a plastic bag.
To satisfy the chilling requirement, many gardeners sow seeds in clear or opaque plastic containers such as milk or soda bottles punched with drainage holes. The containers are partly cut open to gain access to the bottom area for watered potting soil and seeds, then taped shut and set outdoors over winter. Watch for supplemental water needs over the winter.
Butterflies and hummingbirds love coneflower blossoms, and then winter birds such as our trim Oregon juncos feast on their seeds in winter. They and some other birds prefer to gather their own food rather than visiting feeders. They’ll land on a stalk and ride it to the ground, where they’re more comfortable harvest-eating seeds.
A great combination of perennials you could start now is pink-flowering Oriental poppy and flax that features sky-blue blossoms. They complement one another quite nicely. These poppy seeds need light to germinate, as well as moist germinating medium, so may be sowed where you’ll want them to grow permanently or on a sunny windowsill before transplant. Other perennials you could start from seeds now are other perennial poppy varieties, foxgloves, gaillardia, coreopsis, catmint, bee balm and columbine. The late Shirley Barnes, wife of the late former president of Boise State University, Dr. John Barnes, was a native of Colorado, so in her honor they grew the Colorado state flower, columbines, at their retirement home in Boise. Those columbines grew vigorously on the east side of their house, showing their approval of this sun orientation.
Other perennials you could sow now include lupines, one of my favorite ornamentals. Unfortunately they’re short-lived perennials, reappearing only a few springs before they die. Hollyhocks live longer, but are a little difficult to get started. Their first year, you’ll only see a rosette of ground-hugging leaves. They don’t begin blooming until their second growing season, at which time they stretch for the sky. This second-year blooming is typical of many perennials.
Globe thistle, a striking steel-blue perennial, can be started from seed now too. It’s said to be deer-proof, but when deer are hungry, they’re apt to eat anything. In urban settings deer often eat rose shrubs, somehow avoiding mouth injury from the thorns. Deer have been seen in every neighborhood in Boise, undaunted by traffic, fences lower than 7 feet or signs of any kind. Globe thistle is known botanically as Echinops ritro, quite different from Miss Willmott’s Ghost, or Eryngium giganteum. The latter does resemble globe thistle, but is much larger and the blue hue of the foliage/blossoms is paler, even silvery. It’s known as “Miss Willmott’s Ghost” because plantswoman Miss Ellen Willmott so loved the plant that she dropped seeds in appropriate gardens and landscapes. Wherever one popped up, gardeners “knew” Miss Willmott had dropped that seed. It’s also known as giant sea holly, and can become quite invasive.
Chinese lanterns are closely related to tomatillos but this Physalis is poisonous, definitely NOT edible. It may also be sowed at this time. I grew one plant several years ago, and it took forever, it seemed, to begin to grow vigorously. Apparently during that somnolent time it was expending energy on sending out rhizomes throughout the bed so that the plant could take over the entire bed. The runnerlike rhizomes are orange-colored pencil-thick strings, and had we been able to skim the surface soil, the bed would have looked like a newly-strung tennis racket. It was labor intensive to remove this thug.
Send garden questions to firstname.lastname@example.org or Gardening, The Statesman, P.O. Box 40, Boise, ID 83707.