Why not take advantage of azaleas' spread and cover a shady slope with them? While some of us have at least on paper crossed out the big old-timey shrubs in favor of their new diminutive forms, we may have also forgotten how valuable some of these bulky plants can be. Here, Japanese kerria (Kerria japonica) produces its bright-yellow flower clusters in mid-spring. Most of the species grow three to six feet high and a little wider. Will tolerate any soil as long as it's well-drained.
Broadening a Juniper's Reach
Junipers here Juniperus chinensis come in a wide range of heights, including the ground-hugging forms that are ubiquitous throughout residential and commercial landscapes. Junipers are adaptive to a range of soils and do best in full sun, but they also do tolerably well with only a half-day of sun.
If you need to cover ground, there's a wealth of plant choices at your fingertips. Juniper, vinca, creeping phlox, plumbago, carpet bugle and pachysandra all do their part to discourage weeds and reduce the amount of turfgrass that needs to be mowed and maintained. But as great as ground-huggers are, they're low-growing, and flat can be boring if no vertical elements are present. Wide-spreading shrubs, even if they're tall, can function just as well as groundcovers. So if you crave a bit of dimension, perspective, height and extra color in your landscape scheme, consider going up while you're going out. Although we don't tend to think of them in that way, azaleas are good covers of ground, usually spreading wider than they are tall as they mature. Gardeners find it easy to underestimate the eventual girth of a little one-gallon plant bought on sale and sometimes wind up wanting to whack them back. This magnificent mound, measuring at least 30 feet wide, isn't one azalea, though several individual plants contributed to this formation.
In spring the arching branches of drooping leucothoe offer creamy panicles above its evergreen foliage. Great for covering a shady bank, Leucothoe fontanesiana averages three to six feet tall and wide. Look for 'Girard's Rainbow', a cultivar whose new growth is mottled copper, pink, white and green. Leucothoe needs moist, acid, well-drained soil; it doesn't tolerate drought. USDA Zone (4) 5 to 8. Coastal leucothoe (L. axillaris) grows two to four feet high and three to six feet wide. USDA Zones (5)6 to 9.
Groundcover roses are generally considered those roses whose spread is greater than their height. While averaging 3-1/2 feet high and three feet wide, the Knockout series of roses isn't listed among the groundcover roses, but its sensational continuous bloom during the growing season, dense foliage, great habit and low maintenance make this a great plant for colorful hedging and masses. They self-clean so deadheading isn't necessary.
At 1-1/2 to two feet high and four to five feet wide, sweetbox (Sarcococca hookerana var. humilis) makes a wonderful groundcover for shade. Its evergreen foliage looks great all year, and in spring, tiny flowers tucked into the leaf axils give the plant a heady fragrance. Treat this plant as you would an azalea or rhododendron give it moist, well-drained, organic soil. USDA Zones 5 to 8.
Sun to Shade
If the area you want to cover has a mixture of sun and shade, one of the cherrylaurels (English laurel) might be the answer. Prunus laurocerasus 'Otto Luyken' tolerates both full sun and full shade, forming a dense shrub three to four feet tall and twice as wide. Leaves are evergreen, four inches long. USDA Zones 6 to 8.
Green stems in winter and its graceful appearance make it a great plant above retaining walls. For steep banks and other areas too difficult to navigate or maintain, winter jasmine (Jasminum nudiflorum) is a good solution. This deciduous plant (semi-evergreen to evergreen in warmer climates) splays its long branches in all directions, rooting as they go and forming new plants. It produces small, bright yellow flowers sporadically during the winter months, reaching a crescendo of flowering in February. Three to four feet high and twice or more as wide, it's relatively fast at colonizing an area. In fact, you might have trouble getting rid of it if you ever have second thoughts about how to landscape that spot. USDA Zones 6 to 10.