Deb Babcock's gardening column appears Mondays in Steamboat Today.
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If the slope in your garden rivals the pitch of a black diamond ski run, gardening on it can be a real challenge. Mulch and seeds don’t stay put, water immediately runs off, and getting into it for garden maintenance takes the skill of Spiderman.
The rewards of a well-designed slope garden, however, are worth the effort. Especially when the sloped area is prominently located near your home. An area that slopes up from your home is more dominant than one that slopes away and should be designed to complement the contours of the rest of your property and your home.
First, determine the orientation of your slope. Which direction does it face? North-facing slopes tend to be great for woodland gardens while sun-baked west-facing slopes work well for rock gardens.
There are many ways to add interest to a slope garden. Bury boulders or log chunks in the soil and surround with shrubs, trees and groundcovers as well as vines and other plants that will spill over the rocks and wood. Besides adding color, texture and aroma, plants on your garden slope help cover the soil and reduce runoff. Plant roots strengthen the structure of the slope. Remember to match the plants for your slope garden to the environment in which they’ll be planted.
Good tree choices for a sloped garden include Aspen, Ginnala Maple, Gamble Oak, Green Ash, Bristlecone Pine and Rocky Mountain Juniper. Some good shrub choices include low growing Junipers as well as Chokecherry, Cotoneaster, Potentilla, Harrison Yellow Rose, Serviceberry, Western Sandcherry, Vanhoutte Spirea, Staghorn Sumac, Ornamental Grasses, Rabbitbrush, White Sage, Apache Plume and New Mexico Locust.
The following are wonderful perennials and groundcovers for slope gardens: Hardy geraniums, Yarrow, Aster, Pasque Flower, Sea Pink, Silver Mound, Yellow Ice Plant, all the Sedums, Plumbago, Snow-in-Summer, Baby’s Breath, California Poppy, Purple Coneflower, Balloon Flower, Creeping Phlox, Mother of Thyme, Woolly Thyme, Lavender Cotton, Perennial Salvia and Creeping Potentilla.
You can build a low retaining wall or terrace the slope so you have several shorter slopes and some flat areas for foliage, a bench or garden ornaments. Consider stairways or a dry creekbed made of river rocks running through the sloped area.
My down-sloping area that faces south is planted with huge silvery mounds of artemesia interspersed with a dry creekbed, large boulders and tall clumps of ornamental grass. I allow the beautiful straw-colored seedheads of this grass (“Karl Forester” Calamagrostis) to remain throughout the winter for interest in the garden.
My friend, Laura, has an upsloping garden running alongside her driveway. She’s planted a number of pretty ornamental trees and shrubs interspersed with early spring-flowering bulbs followed by a profusion of summer-blooming perennials.
For more ideas on ways to plant on a slope, check out the sloped gardens at the Yampa River Botanic Park.
Deb Babcock is a Master Gardener through the CSU Extension Routt County. Call 970-879-0825 or email CSUMGProgram
@co.routt.co.us with questions.