Extension Master GardenerSM Volunteers of Buncombe County

planting on slopes

Gardening on Slopes: A Recap of Tips and Techniques

For the past few weeks, we’ve shared a series of blogs about gardening on slopes. Here’s a recap of the tips and techniques covered.

Before you plant

  • Spend a year looking out your windows before you ever put the first plant in the ground. What do you see—or would like to see? What problem areas need fixing?
  • Analyze your site, define your goals, and develop a plan.
  • Resolve stormwater runoff problems.
  • Tackle weeds now—and forever.
  • Install steps, paths, and hardscapes.
  • Do research to find the right plant for the right place. Be aware of the growth habits of different varieties within a plant species.

When you plant

  • Camouflage the slope so it’s not so overwhelming to look at. Do this by varying your plant heights, shapes, colors, and textures.
  • Create backdrops and focal points. These are places the eye stops and rests as you survey the garden. Use plants that act as visual markers of slope edges or entranceways to different parts of the garden.
  • Buy plants in small containers—one, two, and three-gallon sizes. They’re much easier to plant than large root balls, they establish themselves quicker, and they will soon catch up in size—and save you money in the process!
  • Slopes can be dry. A drip irrigation system is very effective and eliminates the need to drag heavy hoses up and down the hillside.
  • Reduce maintenance on slopes wherever you can. Fill in with ground covers and evergreen shrubs. Use reseeding flowers. Let your plants grow together and happily cohabitate.
Steep slope garden uses diverse plantings for visual interest, privacy, and erosion control.
Steep slope garden uses diverse plantings for visual interest, privacy, and erosion control.

While gardening on slopes can be challenging, those slopes need not intimidate you. With good gardening practices, you can create a beautiful and enjoyable steep slope garden paradise to enjoy for years to come.

Article written by Beth Leonard, Extension Master Gardener Volunteer.

Gardening on Slopes: It’s Never Ever Maintenance Free

Regular maintenance keeps slope gardens tidy and healthy.Minimal maintenance is an oft-stated and laudable goal when it comes to slopes. But know that there’s never a maintenance-free garden—except maybe Mother Nature’s forests! We maintain to help our plants grow and establish, and to keep our gardens tidy and healthy.

Initially, you’ll find yourself crawling around on your slopes to pull weeds and fertilize new plantings. But if you’re persistent, if you install a good base of mulch or groundcover, and once your plants become established, maintenance gets easier and easier each year. If you’ve selected the right trees and shrubs for the space, you should have to do very little pruning beyond developmental pruning the first couple of years. If you’ve planted or seeded annuals and perennials, you may need to clean up spent flower heads and stems at the end of the season. Ornamental grasses need to be cut back in late winter. If you have grassy paths, you’ll need to string-trim or mow. If your paths are mulch, gravel, or wood chips, you will need to periodically refresh them.

I grab a bucket and walk through my garden once a week, hand-pulling weeds when I see them. This way, they never get out of control. At the same time, I look over my shrubs for signs of disease or insects that need attention. My grassy paths get a string trimming once every three weeks during the growing season. I allow perennials and annuals—echinachea, poppy, heliopsis, coreopsis, and cosmos—to reseed themselves freely on my steep slopes. Then I spend one nice day in December or January removing the spent flower stems and cleaning up the bank. I estimate about four to eight hours a week of maintenance in my half-acre steep slope garden.

My biggest maintenance challenge is replenishing mulch every other year as it decays and enriches the soil. I use double-ground hardwood mulch that knits together and sticks nicely to the slope. Climbing the hills and spreading the mulch one bucketful at a time is not an easy task. But as my groundcovers and shrubs fill in, I need less mulch each year and even this task is becoming easier.

Article written by Beth Leonard, Extension Master Gardener Volunteer.

Gardening on Slopes: Solve Problems with Plants

Sun. Shade. Wet. Dry. Tall. Short. Spreading. Contained. Don’t be intimidated by your steep slope. Start with your objective, identify any gardening problems you need to solve, and then select your plants. With thousands of plants to choose from, you’re bound to find the right ones for your space.

Diverse planting of conifers on slope
Diverse planting of conifers on slope.

Conifers
Low maintenance, erosion control, and all-season interest—especially during winter months—are typical gardening goals on slopes. Our acidic soils and a sunny hillside make an ideal environment for conifers. Nurseries will present you with an almost unlimited variety of conifer shapes, sizes, and colors from which to choose—spruce, cypress (Chamaecyparis spp.), pine, hemlock, arborvitae, and juniper. Conifers require little—if any—pruning, and typically are disease and insect free, making them well-suited for low-maintenance hillsides. Just know the natural growth habit of the variety you select. Is the conifer you choose a tree, shrub, or groundcover? A Norway spruce (Picea abies) can grow into a 90-foot tall tree, while a dwarf globosa blue spruce (Picea pungens ‘Globosa’) will remain a compact shrub, only three to four feet tall. While the variety of junipers can be mind-boggling, there’s nothing better to cover and hold a dry, hot slope than a spreading juniper (Juniperus horizontalis). Just be sure you have enough space because some junipers like ‘Shore’ and ‘Blue rug’ will spread ten feet or more.

Nellie R. Stevens hollies
Nellie R. Stevens hollies hide retaining wall. Daylilies outline path and camouflage lower holly branches.

Hollies
Hollies (Ilex spp.), like conifers, suit our WNC environment. They come in a vast variety of shapes, sizes, and colors. Some are evergreen; other are deciduous. ‘Nellie R. Stevens’ hollies are workhorses and provide outstanding privacy screens. There’s nothing prettier in the winter than the native winterberry holly (I. verticillata) covered with red berries—‘Red Sprite’ is a great cultivar. If you’re looking for an evergreen holly that thrives in moist soils and sends up shoots from root runners to hold soil on steep slopes, try the native inkberry holly (I. glabra). Japanese hollies (I. crenata) are often the perfect size for foundation plantings, but are highly susceptible to diseases, including root rot in poorly drained soil.

Moisture lovers
Shrubs that like wet soil and work especially well near the bottom of a steep slope or in an area that takes lots of stormwater runoff include sweetspire (Itea virginica), summersweet (Clethra alnifolia), and red twig dogwood (Cornus sericea). Plant these, give them lots of room to grow, and ignore.

Ornamental grasses
Ornamental grasses are excellent choices for dry, sunny slopes and they mix well with other shrubs and perennials either in masses or as individual specimens. Your ornamental grasses will need maintenance in the late winter—namely climbing your slope to cut them back to near-ground level just before new growth emerges. For shady spots, think ferns and hostas.

Shrubs for flowers and fall color
Shrubs such as hydrangeas, viburnums, and fothergilla add colorful interest to your slopes. Again, know the growth habit of shrubs you choose. Some viburnums can reach 12-feet tall, hydrangeas may need staking on a steep slope when their spreading branches are heavy with blossoms, and Fothergilla major tops out at 10 feet, but dwarf Fothergilla gardenii is a modest 3-feet tall at maturity.

Perennials and annuals
Speaking of staking—do you want to grow perennials or annuals on your slope? If so, be sure they have sturdy stems or plan on staking them. Tall flowers flop, especially after a heavy rain.

Ground cover: Green-and-Gold (Chrysogonum virginianum)
Green-and-Gold (Chrysogonum virginianum)

Groundcovers
We often want low-growing groundcovers to hold the soil on our slopes and carpet the ground beneath shrubs and trees. I’ve already mentioned creeping juniper for sunny, dry slopes. If your hillside is part sun to shade, try pachysandra—either the native Allegany spurge (P. procumbens) or the Japanese variety (P. terminalis). At less than six-inches tall, spreading, and evergreen, pachysandra makes a pretty groundcover summer and winter. Or you might cover your slope with low-maintenance creeping red fescue—a fine-bladed grass that stays green in winter. Other low-growing choices are green-and-gold (Chrysogonum virginianum) and creeping St. John’s wort (Hypericum calycinum), although both brown out during the winter. Perennials such as dwarf crested iris, catmint, stachys, and ajuga all make good groundcovers on slopes.

Avoid bullies
Warning! Never plant invasive species such as English ivy or periwinkles (Vinca major and V. minor) as a groundcover. And beware other aggressive groundcovers such creeping raspberry (Rubus pentalobus). While only English ivy climbs and helps kill trees, you’ll need to dedicate many gardening hours to pulling trailing vines to keep any of these plants in bounds.

Analyze your site, have a plan, install your hardscape and access paths, and spend time thoroughly researching your plant options. You will then be ready to select the right plant for the right space on your garden slope.

Article written by Beth Leonard, Extension Master Gardener Volunteer.

Contact Us

Buncombe County Extension Office
49 Mount Carmel Road
Asheville, NC 28806
Helpline 828-255-5522

Events

Keep up with our events by subscribing to the blog or checking our Events Calendar.

Explore the Archives

Back to Top