Best Ground Cover Plants For Slopes

Solving Erosion and Aesthetics on Sloped Terrain

Slopes are a common headache in residential and commercial landscape work. Without enough plant cover, even a gentle 15-degree incline can lose several inches of topsoil each year to sheet erosion—threatening foundations, clogging drains, and clouding nearby streams. The American Society of Landscape Architects (ASLA) has long pointed out that vegetative ground cover is usually the cheapest and most ecologically sensible way to hold slopes in place, especially those between 3:1 and 2:1, where mowing gets tricky or unsafe.

Choosing ground cover isn’t just about picking something that looks good. Root structure, drought tolerance, how much upkeep it needs, and whether it fits your local climate all matter. The plants listed here have been tested across several real-world conditions and are regularly used by landscape teams at places like the Chicago Botanic Garden, the Lady Bird Johnson Wildflower Center in Austin, Texas, and the Brooklyn Botanic Garden.

Understanding Slope Gradient and Plant Selection

Before you pick plants, it helps to know your slope’s actual grade. Landscape folks usually describe slope as a ratio—horizontal distance to vertical rise—or as a percentage. A 4:1 slope (25%) is about the steepest most people can safely mow with a walk-behind mower. Steeper grades need low-maintenance ground covers that spread sideways quickly and grow deep roots, either fibrous or taproots.

According to the ASLA’s 2022 Residential Landscape Guidelines, slopes steeper than 33% (3:1) should be planted with species that reach at least 80% canopy coverage within two growing seasons. That helps stop rill erosion during heavy rain—and it’s why the plants below made the list.

Soil type also plays a big role. Sandy, well-drained soils on south-facing slopes dry out fast, while north-facing clay slopes can stay soggy for weeks after rain. Matching the plant to those microclimates makes the difference between success and failure.

Calculating Coverage and Plant Spacing

A rule of thumb many landscape pros use: divide the slope’s square footage by the plant’s mature spread, then add 10–15% extra to account for losses. For a 500-square-foot slope planted with something that spreads 18 inches wide, you’d need roughly 285 to 310 plants. At typical wholesale prices, that number gives you a realistic sense of the plant budget before anything goes in the ground.

Top Performing Ground Covers for Slopes

The following species have held up well on slopes across USDA hardiness zones 4 through 9. Each entry includes the Latin name, typical spread, cost range, and notes on ecological function.

Creeping Juniper (Juniperus horizontalis)

Juniperus horizontalis is probably the most widely used woody ground cover for slopes in North America. Cultivars like 'Wiltonii' (Blue Rug) spread 6 to 8 feet wide but stay just 4 to 6 inches tall, forming a tight mat that crowds out weeds and holds soil with fibrous roots that go 18 to 24 inches deep. It handles full sun, poor soils, and long dry spells once it’s settled in—making it a solid choice for south- and west-facing slopes.

You’ll usually pay $8 to $14 per 1-gallon container, and $18 to $28 for 3-gallon sizes. For a 1,000-square-foot slope, plant material alone runs $400 to $700; add another $300 to $600 for labor, depending on how easy it is to get equipment onto the site. It’s hardy from zones 3 through 9 and rarely needs extra water after its first full growing season.

Crown Vetch (Coronilla varia) — A Cautionary Note

Coronilla varia was planted heavily along highways mid-century because it spreads fast and fixes nitrogen in the soil. It does hold soil well, but the USDA PLANTS Database (2023) now lists it as invasive in 26 states. Staff at the Lady Bird Johnson Wildflower Center strongly recommend skipping it near native plant areas. We’re including it here so homeowners can spot it—and choose safer alternatives instead.

Native Alternatives with Strong Erosion Control

Several native species control erosion just as well as aggressive non-natives—without the ecological risks. Arctostaphylos uva-ursi (Bearberry) spreads 3 to 6 feet wide, handles sandy acidic soils, and feeds wildlife with its red berries. Ceanothus americanus (New Jersey Tea) fixes nitrogen and thrives on dry slopes in zones 4 through 8. Symphoricarpos orbiculatus (Coralberry) grows in both sun and shade, spreads by root suckers to form dense patches, and works especially well on steep north-facing slopes in the Midwest.

Herbaceous and Semi-Woody Options

Woody shrubs aren’t always the best fit. On slopes where looks, seasonal interest, or budget steer you toward herbaceous plants, several options hold up well.

Hemerocallis hybrids (Daylilies) are among the most affordable choices, often $3 to $6 per bare-root division. Their dense, fibrous roots bind soil effectively, and one plant can reach 24 inches wide in three years. The Chicago Botanic Garden’s trials consistently rank reblooming daylily cultivars among the top performers for low-maintenance slope plantings in the Upper Midwest.

Liriope spicata (Creeping Lilyturf) is a semi-evergreen, grass-like perennial that spreads quickly via underground stolons—making it one of the fastest ways to get full coverage on a slope. It tolerates deep shade, so it’s one of the few reliable picks for north-facing slopes under tree canopy. Spacing plants 12 inches apart on a 500-square-foot slope means about 500 plants; at $2 to $4 each in bulk, that’s $1,000 to $2,000 for plants alone—but dividing existing clumps cuts that cost way down.

Hypericum calycinum (Creeping St. John's Wort) puts out bright yellow flowers in summer and spreads by underground runners into a dense mat 12 to 18 inches tall. It grows well in zones 5 through 9 and handles both dry and moderately moist soils. On slopes with partial shade, it often does better than junipers and other full-sun species.

Comparative Performance Data

The table below summarizes key performance metrics for the most commonly recommended slope ground covers. Data comes from university extension trials and reports from ASLA member projects.

Species	Mature Spread	Root Depth	Cost per Plant (1-gal)	Zones	Shade Tolerance
Juniperus horizontalis	6–8 ft	18–24 in	$8–$14	3–9	Low
Arctostaphylos uva-ursi	3–6 ft	12–18 in	$10–$16	2–6	Low–Moderate
Liriope spicata	12–18 in	6–10 in	$2–$4	4–10	High
Hypericum calycinum	2–3 ft	10–14 in	$6–$10	5–9	Moderate
Hemerocallis hybrids	18–24 in	12–16 in	$3–$6	3–9	Low–Moderate
Symphoricarpos orbiculatus	4–6 ft	20–30 in	$8–$12	2–7	High

Installation Practices That Determine Long-Term Success

Even great plant choices can fail if installation isn’t done right. Landscape architects consistently point to three things that make or break a slope planting: preparing the soil, controlling erosion while plants get established, and watering smartly in that first growing season.

On slopes steeper than 25%, bare soil between new plants washes away before they fill in. The standard fix is to lay down biodegradable erosion control blankets (ECBs) made from coir or straw right after planting. These hold soil in place for 12 to 24 months—long enough for most ground covers to get a foothold—then break down naturally. Coir ECBs usually cost $0.15 to $0.25 per square foot installed, adding $75 to $125 to a 500-square-foot job.

"Vegetative establishment on slopes is a race between plant growth and erosive forces. The designer's job is to slow erosion long enough for roots to win that race." — Adapted from ASLA Professional Practice Guidelines, Erosion and Sediment Control, 2021 edition.

Soil prep on steep slopes is different from flat ground. Tilling a steep slope loosens soil and can actually speed up erosion in the short term. Most landscape architects suggest amending only the individual planting holes with compost—not tilling the whole area—and covering the entire slope with a 2- to 3-inch layer of shredded wood mulch to soften raindrop impact and hold moisture.

Irrigation During Establishment

Most ground cover failures happen in the first summer, when new plants haven’t yet grown deep roots to reach soil moisture. Drip irrigation laid along the contour lines—rather than overhead spray, which just runs off steep grades—gets water right to the root zone with little waste. A basic drip system for a 1,000-square-foot slope costs $200 to $400 in materials and usually pays for itself in two seasons by cutting down on replants.

Weed Management in the First Two Years

Weeds are toughest to manage early on, before the ground cover closes in. According to data from the Brooklyn Botanic Garden’s horticultural research program, applying pre-emergent herbicide in early spring can cut annual weed germination by 70 to 85%. Hand-weeding or targeted post-emergent sprays handle stubborn perennials that break through. Once the ground cover reaches about 80% canopy closure, weeds usually drop to a level you can keep up with one or two passes a year.

Budgeting a Slope Planting Project

Realistic cost estimates help homeowners and property managers plan ahead. The numbers below reflect typical residential projects across the continental U.S. in 2024, based on contractor pricing surveys from the National Association of Landscape Professionals (NALP, 2024).

• Plant material: $0.50 to $3.00 per square foot, depending on species and container size
• Erosion control blankets: $0.15 to $0.35 per square foot installed
• Mulch (3-inch layer): $0.20 to $0.40 per square foot installed
• Drip irrigation (basic system): $0.25 to $0.50 per square foot
• Labor for planting and site prep: $1.50 to $3.50 per square foot on slopes steeper than 20%
• Total installed cost range: $2.60 to $7.75 per square foot

For a 1,000-square-foot slope, that’s a total project cost of $2,600 to $7,750. The range depends on plant choices, how hard it is to access the site, and local labor rates. Jobs in dense urban areas—or on slopes needing special equipment—tend toward the higher end.

1. Assess slope gradient and soil type before selecting species
2. Choose species matched to sun exposure, moisture regime, and hardiness zone
3. Install erosion control blankets immediately after planting on slopes over 25%
4. Apply 2 to 3 inches of shredded wood mulch across the entire planting area
5. Establish drip irrigation for the first one to two growing seasons
6. Apply pre-emergent herbicide in early spring for the first two years
7. Monitor for plant failures and replace promptly to prevent erosion gaps

Slope planting is one of the few landscape investments that gets better with time. As ground covers mature and spread, maintenance drops, erosion risk falls, and ecological benefits grow. A well-designed slope planting installed today can run smoothly for 20 to 30 years—a return on investment most other landscape jobs don’t match.