From Steep Slope to Stunning Garden: A Guide to Landscaping Hillside in Zone 7A

Taming the Beast: Landscaping a Steep Hill in Zone 7A

Steep slopes present a unique challenge for any gardener. They’re prone to erosion, can be difficult to access, and often have poor soil. But with the right plants and techniques, a challenging hillside can be transformed into a stunning, low-maintenance landscape. This guide will provide recommendations tailored for Zone 7A, focusing on erosion control, aesthetic appeal, and practicality.

Understanding the Challenge: The Steep Slope

Before diving into plant recommendations, it’s crucial to understand the specific challenges posed by a steep slope. The primary concern is erosion. Water runs rapidly down a steep incline, carrying away soil and potentially causing landslides. Compounding the issue, the soil on a slope is often thin and nutrient-poor, as the topsoil has been washed away over time. The angle of the slope (expressed as a percentage grade) dictates the level of difficulty. A grade of 180-215% is extremely steep, which means that every horizontal foot gains almost two vertical feet. This requires careful plant selection and strategic planting methods.

Key Considerations for Plant Selection

• Erosion Control: The primary goal is to stabilize the soil. Plants with extensive root systems are essential. These roots act like anchors, binding the soil and preventing it from washing away. Fast-growing, spreading plants are particularly useful for quick coverage.
• Sunlight and Soil: Assess the amount of sunlight the slope receives (full sun, partial shade, or full shade). Also, consider the soil’s drainage and pH. A soil test can provide valuable information.
• Maintenance: Opt for low-maintenance plants. Steep slopes are difficult to access for weeding, pruning, and other maintenance tasks. Choose plants that are naturally resistant to pests and diseases and require minimal intervention.
• Aesthetic Appeal: While functionality is key, don’t neglect the visual aspect. Consider plants with interesting foliage, flowers, or fall color to add beauty to your landscape. Think about the overall design – do you want a naturalistic look, a more formal appearance, or something in between?
• Local Wildlife: Consider plants that attract beneficial pollinators or provide food and shelter for birds and other wildlife.
• Pet-Friendliness: If you have pets, choose plants that are non-toxic and can withstand some wear and tear.

Plant Recommendations for Erosion Control and Aesthetics

The following plant recommendations are categorized by their primary characteristics, helping you to make informed choices for your specific needs. Remember to check plant tags or online resources for specific sun, soil, and spacing requirements.

Groundcovers for Rapid Erosion Control

Groundcovers are the workhorses of slope stabilization. They spread quickly, creating a dense mat that holds the soil in place. Their low-growing habit makes them ideal for covering large areas.

• Creeping Thyme (Thymus serpyllum): This fragrant herb forms a dense mat of tiny leaves and produces masses of small, colorful flowers in summer. It’s drought-tolerant, deer-resistant, and can handle some foot traffic, making it a good option for areas where your dog might roam. Creeping thyme comes in various varieties with different flower colors, including pink, purple, and white. It thrives in full sun and well-drained soil.
• Japanese Spurge (Pachysandra terminalis): This evergreen groundcover forms a dense carpet of glossy, dark green leaves. It’s shade-tolerant, making it an excellent choice for slopes that receive limited sunlight. Japanese spurge is relatively low-maintenance and can tolerate a wide range of soil conditions. It produces small, white flowers in spring.
• Creeping Phlox (Phlox subulata): This spring bloomer puts on a spectacular show of color, with a dense carpet of needle-like foliage covered in masses of pink, purple, white, or blue flowers. It prefers full sun and well-drained soil. Creeping phlox is drought-tolerant once established, and is a great option for areas with rocky or sandy soil.
• Bugleweed (Ajuga reptans): Another fast-spreading groundcover, bugleweed forms a dense mat of foliage that can be green, purple, or variegated, depending on the cultivar. It produces spikes of blue, purple, or white flowers in spring. Bugleweed is adaptable to various soil conditions and can tolerate partial shade, making it a versatile choice for different areas of your slope.
• Stonecrop Sedum (Sedum spp.): Sedums are succulents known for their drought tolerance and ease of care. Many varieties are available, offering a range of foliage colors and textures. They’re also attractive to pollinators. Choose low-growing varieties for slopes, such as ‘Dragon’s Blood’ or ‘Autumn Joy’. Sedums thrive in full sun and well-drained soil.

Shrubs for Structure and Color

Shrubs add height and structure to the landscape. They provide a more varied look than groundcovers alone. Consider a mix of evergreen and deciduous shrubs to create year-round interest.

• Dwarf Korean Lilac (Syringa meyeri ‘Palibin’): This compact shrub offers fragrant purple flowers in spring, adding beauty to your slope. It grows to a manageable size, making it suitable for smaller spaces. Lilacs prefer full sun and well-drained soil.
• Cotoneaster (Cotoneaster spp.): Many cotoneaster varieties are available, offering different growth habits and foliage colors. They are generally low-maintenance and drought-tolerant once established. They produce attractive berries in fall and winter, providing food for birds. Choose varieties that are suitable for your zone and desired size.
• Juniper (Juniperus spp.): Junipers are evergreen shrubs that are highly adaptable to various soil conditions and can tolerate drought. They come in many shapes and sizes, from low-growing groundcovers to taller, upright forms. Junipers are excellent for erosion control and provide year-round interest. Consider varieties like ‘Blue Rug’ or ‘Sea Green’.
• Dogwood (Cornus spp.): While some dogwood varieties are trees, there are also shrub forms that are suitable for slopes. Dogwoods offer attractive flowers in spring, colorful foliage in fall, and often have interesting bark. Red-twig dogwoods are particularly striking in winter. They prefer well-drained soil and partial shade.
• Barberry (Berberis spp.): Barberry is known for its thorny stems and colorful foliage. It’s a tough, deer-resistant shrub that thrives in full sun and well-drained soil. Choose from a variety of foliage colors, including red, purple, and gold. Consider the potential for invasiveness in your area before planting.

Perennials for Seasonal Interest

Perennials add bursts of color throughout the growing season. They can be used to fill in gaps between groundcovers and shrubs.

• Coneflower (Echinacea purpurea): This native perennial is a favorite among pollinators and offers vibrant blooms in summer. Coneflowers are drought-tolerant and easy to grow. They prefer full sun and well-drained soil. Choose from a variety of colors, including purple, pink, white, and orange.
• Black-Eyed Susan (Rudbeckia hirta): Another native perennial, Black-Eyed Susans provide cheerful yellow blooms with dark centers. They are drought-tolerant and easy to care for. They prefer full sun and well-drained soil.
• Daylilies (Hemerocallis spp.): Daylilies are incredibly versatile perennials that come in a wide array of colors and bloom times. They are adaptable to various soil conditions and are relatively low-maintenance. They can tolerate some shade, but they bloom best in full sun. Choose varieties with different bloom times to extend the flowering season.
• Lavender (Lavandula spp.): This fragrant herb produces beautiful purple flowers and attracts pollinators. Lavender thrives in full sun and well-drained soil. It’s drought-tolerant and relatively low-maintenance. Consider planting a mass of lavender for a stunning visual and aromatic effect.
• Sedum (Sedum spp.): While also listed as ground cover, some taller varieties of sedum can be planted among shrubs and ground cover to provide more seasonal interest.

Grasses for Texture and Movement

Ornamental grasses can add texture, movement, and visual interest to your slope. They are also relatively low-maintenance and drought-tolerant.

• Little Bluestem (Schizachyrium scoparium): This native grass provides beautiful blue-green foliage in summer, turning reddish-bronze in fall. It’s drought-tolerant and easy to grow. Little Bluestem prefers full sun and well-drained soil.
• Switchgrass (Panicum virgatum): Another native grass, switchgrass offers a variety of foliage colors and textures. It produces airy seed heads that add visual interest. Switchgrass is adaptable to various soil conditions and can tolerate both full sun and partial shade.
• Feather Reed Grass (Calamagrostis x acutiflora ‘Karl Foerster’): This upright grass provides a vertical accent to the landscape. It’s relatively low-maintenance and tolerates a wide range of soil conditions. Feather reed grass prefers full sun and well-drained soil.

Planting Techniques for Steep Slopes

• Soil Preparation: Since the soil on a steep slope is likely to be poor, amend it before planting. Incorporate organic matter, such as compost or well-rotted manure, to improve drainage and fertility. Consider a soil test to determine the pH and nutrient levels of your soil.
• Planting on Contour: Plant in rows that follow the contours of the slope. This helps to slow down water runoff and prevent erosion. Avoid planting in straight lines up and down the slope.
• Terracing (Alternative): While terracing may not be a current option due to your dog, consider the long-term benefits. Terracing creates level planting areas, making it easier to manage the slope and reducing erosion. If possible, explore options for containing your dog in a designated area to allow terracing to take place.
• Mulching: Apply a thick layer of mulch around your plants to help retain moisture, suppress weeds, and further prevent erosion. Use organic mulch, such as wood chips or shredded bark, which will decompose over time and improve the soil.
• Watering: Newly planted slopes require regular watering until the plants are established. Water deeply and less frequently to encourage deep root growth. Consider installing a drip irrigation system for efficient watering.
• Erosion Control Fabrics: On very steep slopes or in areas with severe erosion, consider using erosion control fabrics, such as jute netting or coir mats. These fabrics help to hold the soil in place while the plants become established.
• Planting Density: Plant closely together to provide rapid coverage and further reduce erosion. Over time, the plants will fill in the space, creating a dense mat that stabilizes the soil.
• Staggering Plants: When planting multiple plants of the same species, stagger them in a zig-zag pattern. This provides more complete coverage and improves erosion control.

Long-Term Maintenance and Care

• Regular Inspections: Regularly inspect your slope for signs of erosion, such as rills or gullies. Address any problems promptly before they worsen.
• Weeding: Remove weeds promptly to prevent them from competing with your plants for resources. Weeding can be challenging on a steep slope, so choose plants that are naturally weed-resistant.
• Pruning: Prune shrubs and other plants as needed to maintain their shape and health. Prune in the appropriate season for each plant species.
• Fertilizing: Fertilize your plants sparingly, as excessive fertilizer can promote excessive growth and make plants more susceptible to pests and diseases. Conduct soil test to determine what nutrients your plants need.
• Monitoring: Pay attention to the overall health and appearance of your plants. Address any problems promptly to prevent them from becoming serious.

Conclusion

Landscaping a steep slope is a rewarding project that can transform a challenging area into a beautiful and functional part of your yard. By selecting the right plants, using appropriate planting techniques, and providing ongoing maintenance, you can control erosion, add visual interest, and create a low-maintenance landscape that you can enjoy for years to come. Remember to assess your specific site conditions, choose plants that are well-suited to your climate and soil, and prioritize erosion control above all else.