Here’s a another good article by Jenny Crane for best plant ideas for sloping terrain from Better Homes & Gardens.
Sloped yards can pose planting and landscaping problems. Incline issues are easily remedied with the right plants that are built to thrive on slopes.
Very few yards are perfectly level, and most have ditches or hills that make landscaping a challenge. Flower beds on sloped areas often suffer from erosion that displaces the soil and exposes the delicate roots of plant. There are many plants that are able to fill in the open spaces and have strong and deep roots that will hold plants in place. Here are some of our favorite plants for slopes.
Hellebores are durable flowering plants with the added bonus of being early bloomers—they can often sprout up when there is still snow on the ground. These flowers come in many colors and have a freckled pattern on the petals. Plant hellebores on a slope in full shade or dappled shade for the best results.
Boxwood shrubs are sturdy and dense enough to be reliable hedge and topiary plants, making them a great choice for sloped landscapes. Although hardy, these shrubs prefer drained soil and won’t do well in standing water. When choosing a variety (since there are so many), be sure to research the light and watering requirements for that specific type before placing it anywhere in the yard.
Add roses to a slope for added color and elegance. Most types of roses are good for erosion control and do well in sun to part sun. ‘Falstaff’ is a fuchsia English rose variety with tight, lacy petals that look like a peony’s. Get a completely different look from the same species with ‘Carefree Spirit,’ a bright pink Floribunda rose. The open, sparse petal arrangement leaves the textured center exposed.
Japanese maples are a dwarfed, more delicate version of the classic maple tree. Like maples as a whole, they do well on slopes. They have smaller, more ornate leaves that come in hues of purple, gold, orange, red and green. Most varieties stay under 25 feet, and some only get to be 8 feet tall.
Hydrangea shrubs have strong branches and tons of clustered color when in bloom. They work as great garden bed fillers and are able to hold their own on an incline. Because there are so many types and varieties of hydrangea, be sure to check the label for light requirements before planting.
Climbing roses are tough and great for slopes. The can vine up trellises or fences to create privacy, and have multiple blooms to add color to landscaping. Give climbing roses a sunny spot to keep them happy.
Most groundcovers are built to sprawl and cover exposed soil, which helps these plants stay put on a slope. Allowing these plants to take over will help reduce the amount of runoff, and gives a sloped garden a more finished look. Try tough groundcovers like ajuga, hen and chicks, brass buttons, and thyme for delicate texture and solid soil stabilizers.