The Genus Artemesia
This is a large genus of herbaceous perennials and shrubs, mostly from cool climates of Africa, Asia, Europe, North America and South America. I have not explored this genus thoroughly. At least a few ornamental species are sufficiently heat and humidity tolerant to thrive in the Coastal Southeast. Some of the gray-leafed Artemisia species are known by the common name of dusty miller. Jacobaea maritima is another common garden plant that is known as dusty miller
The aster family, Asteraceae, is a huge family of herbaceous and woody plants that is found around the world. Only the orchid family rivals the number of the Asteraceae. They may be annuals, herbaceous perennials, shrubs, trees or vines. Important members of the family include tickseed (Coreopsis,) blanket flower (Gaillardia,) sunflower (Helianthus,) goldenrod (Solidago,) marigold (Tagetes,) ironweed (Vernonia) and zinnia (Zinnia.)
Artemesia vulgaris ‘Janlim’ (syn. Artemesia lactiflora)
This is a stoloniferous, herbaceous perennial to about six to twelve inches tall. The stems die back to the ground but leaves at the surface remain evergreen, usually. This variegated variety is grown mainly for its foliage and the two to three foot tall flower spikes may be removed as they develop in late summer. It is at its best as a somewhat aggressive groundcover with room to spread. Because of its rapid growth rate, it is not a good plant for a small, formal garden. It grows well in sun to part shade, in a moist, well-drained soil. References state that it grows from zone 4 to 8 but it has proven itself to be vigorous in northern zone 9a.
This plant is available in local nurseries. Propagate by summer cuttings or division.
Plants in my zone 9a gardens spread rapidly where irrigated but struggle to survive in drier sites. They die down with the first freeze. They resprout in late winter.
Artemesia x ‘Powis Castle’
Powis Castle dusty miller
This is an evergreen herbaceous perennial that grows to two to three feet tall and several feet wide. It is reported to be a hybrid between A. arborescens and A. absinthium. It has a beautiful, deeply dissected, silver-gray foliage. It is best in a sunny site, in a reasonably moist, well-drained soil. I found it listed as a salt tolerant plant by one site. Various references give a wide range of hardiness information. It is reported to be reliably cold hardy from zone 6 to 9, possibly into zone 5.
This plant was popular for a while but seem to have disappeared from local nurseries. It is available in mail order catalogs. Propagate by summer cuttings.
My plants struggled and died in zone 9a before I realized that they are not drought tolerant enough for prolonged summer droughts in the sandy soil of my home garden. This plant grows very well in a container of good potting soil with regular irrigation but remains a short-lived perennial that tends to die out in its second summer.