The Best Perennial for Slopes

Willow Blue-Star

• Willow blue-star (Amsonia) is a unique native perennial with willowlike foliage and star-shaped blue flowers that appear in late spring. Willow blue-star is native to most of the southeastern, eastern and central United States. Willow blue-star reaches a mature height of 1 to 3 feet and performs best in full sun or partial shade. It is a low maintenance plant once established and is ideal for rocky slopes and dry areas. Plants grown in moist soil generally grow closer to 3 feet. In the fall, the willowlike foliage turns a golden-yellow color. Willow blue-star is hardy in U.S. Department of Agricultural plant hardiness zones 3 through 9.

Daylily

• Daylilies are colorful plants that come in a wide range of heights -- from a mere 8 inches to 5 feet tall. The flowers come in almost every color of the rainbow and bloom from late spring into fall. The flowers last just one day, or in the case of night-blooming daylilies, just the one night. Some varieties, such as Stella D'Oro will bloom all summer long, but most daylilies are not repeat bloomers. Daylilies are long-lived plants that thrive on neglect. They spread by underground rhizomes. As they multiply, the rhizomes become so thick that grass or other weeds cannot penetrate them. Daylilies are hardy in plant hardiness zones 3 through 9.

Hosta

• Hostas are popular shade plants that are primary grown for their interesting foliage, although a few varieties will tolerate some sun. Some hosta plants have foliage that is a single color, some have multicolored foliage and some have foliage with colored edges. The foliage colors come in shades of blue, green, gold and white. Hostas range in size from miniature varieties that are a few inches in diameter to large varieties that are more than 8 feet wide. Hostas produce white or lavender spikes of lily-shaped flowers in mid- to late summer. Some of the flowers are fragrant and some are not. Hostas do need require watering to keep them looking their best. Hostas will form mat as they multiply, making them ideal for growing on slopes. Hostas are hardy in hardiness zones 3 through 10.

Milkweed

• There is nothing quite like a large slope covered in milkweed for attracting hummingbirds and butterflies that drink the nectar of and lay their eggs on these plants. Once the caterpillars hatch, they will eat the milkweed leaves, which can make a planting look scraggly. Milkweed is a native plant that produces a long taproot, making transplanting difficult; so instead of digging plants you find at the side of the road, purchase plants from a nursery, or plant seed in the fall. Depending on the variety you choose, the pink, purple, white, red, yellow or orange flowers will bloom from June through October. Some varieties of milkweed prefer boglike conditions while other varieties prefer dry soil. Depending on the variety, milkweed is hardy in zones 4 through 9.