Silver mound artemisia is a low-growing perennial that forms a mounded shape covered with fine, silky, silver-gray foliage. As an ornamental, the silver mound artemisia makes an attractive border plant or ground cover. It is drought tolerant and suitable for rocky, poor soil conditions, features that lend themselves well to rock garden specimens. The scientific name is Artemisia schmidtiana. This variety, also known by its cultivar name Nana and the common name satiny wormwood, is the only artemisia that grows low to the ground in a compact, clumping formation.
Silver mound artemisia reaches mature height between 6 inches and 18 inches (about 15 cm to 45 cm) tall, forming mounds from 12 inches to 18 inches (about 30 cm to 45 cm) wide. The foliage is delicate with a silky texture and a matted, wooly appearance on short, woody stems. In late August, small yellow flowers emerge from silver buds under the foliage. The flowers are often overlooked and can be removed to improve the health of the plant and the appearance of the foliage.
This ornamental perennial should be planted in full sun or partial shade. Sandy loam and well-draining, moist soil conditions with relatively poor nutrition will encourage this ornamental to reach its most pleasing shape in optimal health. Wet, heavy soils will cause the roots to rot, and standing water is likely to kill the plant. Soil rich in nutrients will encourage the mound to split apart and grow in a spindly fashion by late summer. Silver mound artemisia is tolerant of rocky soil, heat and drought; in humid or wet conditions, the plant is liable to suffer from stem rot and foliage rust.
The individual clumps of the silver mound artemisia spread in a slow, non-aggressive fashion, unlike other members of the artemisia family that tend to be moderately invasive. When planting a ground cover or border, the individual plants should be spaced from 15 inches to 18 inches apart (about 38 cm to 45 cm). In late summer or early fall, the mound is likely to split apart when planted in a garden or area with good soil and nutrition. To prevent this unattractive feature, the foliage should be cut back to half its mass in summer, before the flowers emerge.
The neutral, silvery foliage is often used as a backdrop for other cool color, flowering perennial plants. Purple, lavender, blue, pink, and magenta stand out against the silver foliage. It is often planted under taller shrubs and trees to form a soft, neutral ground cover.