Top 7 Shrubs for slopes

Tricky slopes are no match for these fast-growing, low-maintenance plants

Whenever I drive down the road and see a rickety, out-of-control slope or a barren, mulch-filled slope, my heart goes out to the person tending that land. Without a doubt, gardening on an exposed slope can be an absolute nightmare. It seems almost impossible to establish any plantings. Heavy rain flows like a river, carrying away any topsoil not held by the roots. During periods of drought, the soil becomes bone dry and inhospitable to desirable plants trying to thrive, while weeds grow bigger and better.

As a landscape designer in the hills of central Virginia, I know the conundrum of planting on slopes well. As a result, I've developed a plant arsenal that consists of low-growing, slope-friendly shrubs that can take a beating and gain ground more quickly. For cutting, shrubs must have a vigorous, soil-holding root system and a tight mesh of shoots that disperse heavy rainfall. I avoid plants with excessive pest or disease problems that are too far from their original planting site. Thornless shrubs always make maintenance a little easier. Plants that retain leaves early in fall and into fall, however, rise to the top of the pile. Here are seven great plants I use to tackle challenging slopes.

1. Dwarf Forsythia

Like other varieties in this genus, Gold Tide™ Dwarf Forsythia (Forsythia 'Cordazol', USDA Hardiness Zones 5-8) is tough as nails. However, the biggest difference from the others is in its shape. Cold Tide's stems only reach 18 inches tall. Its abundant, grapefruit yellow flowers appear in early spring.

Plants are reported to grow well in zone 5, but have smaller flowers due to frost damage. In frost-covered areas, flower buds are often undamaged. For best results, set the soaker hose on a timer until the dwarf forsythia is established. The plants bloom best in full sun and adapt to any soil. If the dwarf forsythia is too entangled with its neighbors, cut the stems back hard after flowering.

2. Golden St. John's Wort

Golden St. John's Wort (Hypericum frondosum 'Sunburst', Zones 5-8) is another ground cover shrub that can make a slope sheltered and colorful. Bright yellow flowers open in the first half of summer, followed by attractive, rust-colored fruit capsules. Although other Hypericum species are suitable for slopes, I think golden St. John's Wort is one of the best. This native is a vigorous grower reaching 3 feet tall. It has a wide hardiness range and will not return in areas beyond your planting site.

Golden St. John's Wort thrives in calcareous or acidic soils. It thrives in full sun or partial shade and is generally happy with life. Because St. John's wort blooms on new growth, pruning should be done in the spring before new shoot growth. For a succession of yellow flowers, plant golden St. John's wort with dwarf forsythia. Stephanandra and Spirea nipponica 'Snowmount' (zones 4-8) are good, non-fighting companions that work together to form a harmonious, weed-free mass.

3. Winter jasmine

Winter jasmine (Jasminum nudiflorum, zones 6-9) is a hillside gardener's dream. This mounding shrub quickly gains ground as its trailing branches form roots when it touches the soil. Plants burst with yellow flowers in winter or early spring, beginning in early January in a mild winter. The flowering period is long, at least five weeks, which starts and stops according to the weather. The only drawback is that the flowers have no scent.

Winter jasmine grows 4 to 5 feet tall in full sun or shade. It is easy to grow and thrives in moist soil. Plants do best in soil amended with organic matter and given extra water until they become established. If they outgrow their space, cut the plants 1 to 2 feet above the ground after flowering. Winter jasmine pairs well with 'Edward Goucher' Abelia (Abelia 'Edward Goucher', Zones 7-9), another densely growing hillside plant that produces attractive pink flowers in summer.

4. Cutleaf stephanandra

Cutleaf Stephanandra (Stephanandra incisa 'Crispa', Zones 3–8) is my favorite for sunny or shaded locations. It does an amazing job of concealing droopy eyelids without becoming a menace. Its small, maple-like foliage casts a stunning sweep of green throughout summer before turning red in fall. Its small, creamy flowers often go unnoticed in late spring, but that's only a minor drawback.

Cutleaf stephanandra receives a dose of composted organic matter at planting time. If your site is dry, afternoon shade will help this plant thrive. Plant it in the middle of a slope so that it flows down like a small bright green stream. If there is an area protected from winter winds in the northern part of its range, take advantage of that shelter.

5 'Texas Scarlet' is a flowering quince

'Texas Scarlet' flowering quince (Cenomeles × superba 'Texas Scarlet', Zones 5-9) blooms and is sold immediately by most gardeners. Although only on display for a week or two in early spring, the display of tomato-red flowers is unforgettable. For the rest of the season, 'Texas Scarlet' is a wave of glossy green leaves that can reach 2 to 3 feet tall in hard conditions.

'Texas Scarlet' is an easy plant to establish in full sun to partial shade. However, in warm and rainy seasons, the leaves may succumb to a fungus that is spread by splashing water and can cause leaf spot and defoliation in late summer. Cleaning up fallen leaves is the best way to mitigate future infestations. Leaf drop can leave a hole in the late garden, so I rely on hardy companions like bush clover (Lespedeza spp. and cvs., zones 5-8) to cover the gaps.

6. Chenault coralberry

Like Stephanandra, Chenault coralberry (Cymphoricarpos × Chenaultii 'Hancock', Zones 4-7) is an undemanding workhorse. No audience will say “Wow”; However, you say it quietly to yourself. This 2-foot-tall shrub can spread to about 10 feet without any problems. It does a great job of covering the ground and suppressing weeds while eliminating erosion. In late summer, small pink flowers appear followed by rosy red fruits.

Chenault coralberry adapts to full sun or shade and is easy to grow. It thrives in a variety of soil types. If this shrub spreads too far, it can be kept under control with pruners, and the rooted stems can be easily cut off and dug up for your slope-infested friends.

7. 'Grow-low' sumac

To some gardeners, sumacs (Rhus spp. and cvs., zones 2-10) are nothing more than roadside weeds. For many plant lovers, however, these remarkably cold- and heat-tolerant natives are making a comeback. One of my favorites is a low-growing cultivar named 'Gro-low' (R. aromatica 'Gro-low', Zones 2-8). This rugged shrub is not like your everyday sumac and is made to cover slopes. It quickly grows up to 2 feet tall and 8 feet wide. 'Cro-Lo' sports small yellow flowers in mid-spring and beautiful orange-red leaves in fall. Although it has an open, branching habit, weed growth does not seem to be a problem.

Sumacs are said to do poorly in heavy, wet soils, but 'Cro-Lo' does well in the loamy soils of central Virginia. For best fall color, grow this shrub in full sun—plants tolerate partial shade. 'Gro-Lo' needs a lot of space to spread. But if its vigorous growth gets out of hand or it becomes untidy, cut it back hard in the spring. Avoid pairing this sumac with smaller, tender plants that can crowd. Consider other hardy growers like Golden St. John's Wort as planting companions.