Extension Master GardenerSM Volunteers of Buncombe County

Landscape Design

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: What about Irrigation?

Because steep slopes tend to be dry, plants may need irrigation, at least until they are well established. The most effective way to provide moisture on slopes is by drip irrigation, either with soaker hoses or perforated pipe. It’s easy for a gardener to install soaker hose, but you’ll probably want to hire a professional for an elaborate irrigation system with timed zones and buried pipe.

Soaker hoses
If you choose to use soaker hoses, run regular garden hoses from your house hose bib to the top of your hill. Then connect your soaker hose to the garden hose at the high point. Snake the soaker hose back and forth across the slope, but keep it continuously moving downhill. Circle the soaker hose a couple of times around trees and large shrubs. For large areas, you may need several downhill soaker hose runs. Toggle switches can be used to switch the water flow from one hose to another. Use metal pins to secure the hose to the slope and then bury it under mulch. A good covering of mulch—such as ground hardwood or pine fines—will reduce your irrigation requirements by helping to retain soil moisture and keep plant roots cool. 

How much to water?
The general rule for watering gardens is to apply one inch of water per week. It may take up to 1½ hours of continuous irrigation to distribute an inch of water through a soaker hose system. On slopes, it’s best to cycle the water flow on and off every 20 to 30 minutes. Water for 20 minutes, then let the water soak into the slope for 20 minutes, then water again for 20 minutes until you’ve applied the needed amount of water. On and off cycling reduces runoff down the slope and encourages more water to soak deeply into the soil.

Article written by Beth Leonard, Extension Master Gardener Volunteer.

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

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