Artemisia — Wormwood, Mugwort, Sagebrush
Plants in the genus Artemisia are native to the Northern Hemisphere and are commonly called wormwood, mugwort, and sagebrush. There is an artemisia suitable for nearly every climate zone; some are native to Sonoma County.
Of the hundreds of species, only a few are used in landscape design; however, of these, several are ideal for the very casual, low maintenance, arid garden. Deer do not like their fragrance or flavor, but aphids do sometimes feed on early spring growth; otherwise, this rugged plant is quite pest resistant and not prone to any diseases.
Artemisia dislikes excess water and fertilizer, but irrigation is necessary to help establish shrubs; then, occasional watering is generally all that is needed.
Artemisia’s color variations, sizes, sculpted shapes, and tolerance of both cold and wet winters invite many uses in Sonoma County gardens. In full sun the silvery gray color enhances both light and deeply colored companion plants—especially dark green, deep maroon, and burgundy. Variations in both hue and texture are pleasing to the eye, but care should be taken to group only those plants with similar cultural needs: no fertilizer, very little water, full to part sun, and good drainage.
Artemisia lactiflora (white mugwort): Native to western China, this clumping perennial bears deeply lobed dark green foliage on lower stems that are topped with tall plumes of creamy white flowers in late summer to mid-autumn. The astilbe-like blooms make it useful as a bedding plant and for fresh cut or dried flowers. This species is one of the few in its genus that takes some shade and rich, moist soil. It grows up to 5 ft. tall and spreads 2-3 ft. wide.
Artemisia ’Powis Castle’: This garden favorite is the most widely available artemisia in Sonoma County. It has airy, gray-green, lacey foliage on woody stems that reach 3 x 4-6 ft. but is easily shaped, even with severe pruning. Tough and versatile in low-water landscapes, it enhances other low-water plants. In part or filtered sun, the foliage becomes more gray green; in full sun, the silver hues dominate.
A. pycnocephala’David’s Choice’ (sandhill sage): A native from Pt. Reyes and northern California beaches, this 1-ft. high and wide small shrub also thrives inland with the same easy care as other artemisias: good drainage and very little water after established. The rounded, compact form of blue-gray, delicate foliage becomes ragged after 2 years and should be replaced.
A. schmidtiana ’Silver Mound’ (angel’s hair): Soft, silky, silver gray fragrant foliage forms a 1-2 ft. mound with small white or yellow flowers and is suitable for rock gardens, front of the border, and containers. Give it slightly dry, average soil.
A. stellerana ’Silver Brocade’ (beach wormwood, dusty miller): This fast-growing silvery spreader has leaves similar in size and shape to flat leaf parsley. As a groundcover to 2 ft. x 3 ft., it can be used to soften the edges of walkways or even to cascade in hanging baskets. It takes full sun, little water, and contrasts easily with white, yellow, blue, reds, and maroon.