Hostas: emperors of the shade
Few plants add more interest to shady areas than hostas.
Native to the Orient, where they were discovered as early as the eighth century, hostas are low-maintenance, winter-hardy perennials that can grow in the shade. Their leaves come in a variety of sizes, shapes, colors and variegation, according to University of Missouri Extension horticulture specialist David Trinklein.
There are about 70 species and more than 4,000 cultivars of hostas available, Trinklein said. They range in size from miniatures that measure only several inches to giants with heights and spreads of up to 48 inches.
Leaf color varies among solid colors of green, blue and yellow or variegated, Trinklein said.
"Like day lilies, hostas bear a compound inflorescence known as a scape," Trinklein said. "Individual flowers on the spike are lavender or white, depending upon cultivar. Some flowers are delightfully fragrant, adding further appeal to this attractive plant."
Although hostas are considered shade plants, most do not thrive in deep shade. They grow best in several hours of morning sun followed by afternoon shade, or broken patches of sun and shade. However, most of the more sun-tolerant cultivars will exhibit some leaf-edge burn if exposed to Midwest afternoon sun and heat, Trinklein said.
Hostas are available as dormant divisions, but they can be purchased as plants already started in nursery containers.
To plant, remove the hosta from its container and free any untangled roots. Place the plant in the planting hole so that the roots will be covered with soil to the same level they were in the nursery container.
If planting dormant divisions, soak the roots in water for about 30 minutes before planting. In either case, water hostas thoroughly after planting.
Hosta experts disagree on how or if to fertilize hostas. Some growers maintain that most garden soils contain sufficient nutrients, and so hostas do not need additional fertilization. Others recommend adding a granular complete fertilizer such as 12-12-12 or 5-10-5 early in the spring, followed by two additional applications, each about six weeks apart.
If fertilizer is added, don't fertilize hostas after mid-July, which would stimulate late-season growth and prevent the plant from hardening for the winter, Trinklein said.
Hostas need about an inch and a half of water per week during a typical summer. Burned leaf tips and drooping leaves are signs that the plants aren't getting enough water.
Hostas can be easily increased by dividing the clump early in the spring when the shoots start to emerge from the soil. Most cultivars, however, should not be disturbed for about five years after initial planting to let the clump establish itself, Trinklein said.
Slugs, snails and deer are fond of these shady plants. Poison baits containing metaldehyde or iron phosphate are effective in controlling slugs and snails, Trinklein said. Pans of beer placed near hostas also attract these pests, which will crawl into the pan and drown.
For more information from MU Extension on lawn and garden topics, including free publications, articles and online resources, visit www.extension.missouri.edu/LawnGarden.
More information about hostas is available from the American Hosta Society at www.hosta.org.