When planting a sloping garden the site conditions must be considered, including sun exposure, type of soil, steepness and stability. Drought-tolerant, low-maintenance, native plants are a good choice for any slope because they grow well in the area, require little water outside the rainy season and require minimal upkeep. They can be a mix of ground cover, flowering plants and shrubs, and ornamental grasses. Include pea gravel, rocks and boulders in a sloping garden.
Perennial Ground Covers
Choose ground covers that grow rapidly in your zone; they will help prevent erosion. One low-maintenance ground cover that fares well in intermountain and mountain regions is bishop's weed. It's a rampant spreader and requires moderate water. Another choice for this region is poppy mallow, which thrives on slopes and requires little care. In a Mediterranean or dessert climate, consider the daisy family, particularly the Osteospermum fruticosum. It's referred to as "the freeway daisy" in California because it is hardy, easily grown and clings to slopes. It also has colourful flowers.
Flowering Plants and Shrubs
Members of the daylily family are perfect for slopes and grow in about every USDA zone except where winters are very mild. They can be evergreen, semi-evergreen or deciduous. They are known for their toughness, adaptability and ease of growth. The golden "Stella de Oro" daylily is particularly good on a slope. Another choice is the flowering and fragrant jasmine. Certain species grow well in many climates and adapt to different soils. The spiraeas, particularly Spiraea japonica, native to Japan and China, is recommended for slope planting. It blooms with pink flowers.
Pampas grass grows well in a Mediterranean climate. It is native to Argentina. It grows fast and will anchor a sloping garden. It grows well in full sun with rain water as its only irrigation source. For a silver-grey splash on a slope, try blue oat grass, native to Mediterranean regions. It grows year-round in mild climates but will turn wheat-coloured with hard freezes. It thrives in full sun and moderate water.
Pea Gravel, Rocks and Boulders
Another way to give structure to a sloping garden is to incorporate pea gravel, rocks and boulders. The larger rocks will help retain moisture in the garden; ground cover can also grow over them. Smaller areas of coloured pea gravel can complement perennials and prevent erosion.