The genus of Artemisia contains about 300 species of plants. It is in the Asteraceae, (daisy) family, but you will not see a lot of showy flowers with this plant. Most artemisias are grown as foliage plants and valued for their filagree-like leaves. Some you might be familiar with are southernwood (A. abrotanum); wormwood, also called absinthe (A. absinthium); mugwort (A. vulgaris); sagebrush (A. tridentata); and the culinary herb called tarragon (A. dracunculus). Artemisia is often considered an herb, either culinary or medicinal. Most of the species are heavily scented and many have a somewhat bitter taste, which makes them very unattractive to browsing animals but useful for their essential oils.
Artemisias have alternate leaves in various shapes. Very often the leaves are lobed, and they are generally covered with whitish hairs that give the leaves a silvery, grayish look. Their flowers are small (1/16 to 3/8 inches), white or yellow, and cylindrical. The flowers are often clustered in panicles, but sometimes they are single.
Many artemisia species are considered invasive in some parts of the U.S. Make sure to check with a local expert before planting, and take care to prevent your plants from escaping into surrounding land.
|Botanical Name||Artemisia spp.|
|Common Names||Artemisia, wormwood, absinthe, southernwood, mugwort, plus sagebrush (shrub form) and tarragon (a common herb)|
|Plant Type||The genus contains a diversity of plant types, including evergreen and deciduous shrubs, perennials, and annuals.|
|Mature Size||From 1 to 5 feet tall depending on variety|
|Sun Exposure||Full sun|
|Soil Type||Any average, well-drained soil|
|Soil pH||Any soil pH.|
|Bloom Time||August to September|
|Flower Color||White or yellow|
|Hardiness Zones||Varies according to variety; A. abinthium is hardy in zones 4 to 9|
|Native Area||Depends on variety, but A. absinthium is native to Eurasia and North Africa, A. tridentata to the North American West|
How to Grow Artemisia
Artemisias are relatively low maintenance, but they do have some preferences when it comes to their growing environment. They will grow best in a full sun location, although most varieties can handle partial shade. Plants can be started from seed, divisions, or cuttings. Many of the newer hybrids are sterile and the others will not grow true to seed.
Artemisias grow best in full sun.
With a few exceptions, such as Artemisia lactiflora, Artemisias need well-draining soil on the dry side. If left sitting in damp soil, they will decline and/or be short-lived.
As with most silver-leaved perennials, they are very drought tolerant. They will need regular water until the plants are established, but they can take care of themselves after that.
Artemisias do not like overly rich soil. Since artemisias do not like rich soil, no supplemental fertilizer should be necessary if you are regularly adding organic matter to your beds.
Perennial artemisias can be cut back in the fall or spring. Shrubby varieties should be pruned in the spring. They can handle being cut back hard if you want to keep their size in check. Even non-woody artemisias can get floppy, especially after flowering. Give them a shearing mid-summer to prevent them from splitting open in the middle.
Varieties of Artemisia
There are many different artemisia species, hybrids, and cultivars, and some are better suited to certain uses than others:
- 'Silver Mound', 'Silver King', and 'Silver Queen': These three are popular in the landscape and have similar-sounding names. But A. schmidtiana 'Silver Mound' is a mounding, compact type (1 foot tall) that can function as a ground cover. A. ludoviciana 'Silver King' and A. ludoviciana 'Silver Queen' are erect and taller (up to 5 feet), making them nice for cutting for arrangements. Both are aggressive and useful when mixed with other plants in short hedges. 'Silver Queen' has more finely cut foliage. All are among the most cold-hardy kinds (to at least zone 4).
- Artemisia 'Powis Castle' grows in a shrubby mound that is bigger than that of 'Silver Mound' (2 to 3 feet tall). It has very delicate-looking, deeply cut, gray leaves. It can become woody and looks best if cut back severely before new growth starts in the spring. It is less cold-hardy than most (to zone 6). It is useful in small hedges.
Propagating Artemisia Plants
Divide plants every two to three years, or when you start to notice the center beginning to die out. This is a simple matter of digging up the entire plant, dividing the root ball, and replanting.
Luckily, if the conditions are ideal, artemisias are quite resilient. Because of their strong scent, insects tend to avoid artemisias. But artemisias can be prone to many fungal and rusts diseases, like white rust, powdery mildew, and downy mildew. Hot, humid weather exacerbates these problems. Growing them in an open area with good airflow will help mitigate the problems.
A vignette of all silvery and white plants looks striking in semi-shade, such as artemisia with lamb's ear (Stachys byzantina), Pulmonaria, and white variegated grass. Gray leaves also pair nicely with just about any pastel, especially pinks and blues, as well as with mauve-pinks, like Joe Pye Weed (Eupatorium) and Centranthus ruber.
A beautiful use for artemisias is to pair them with the spiky, deep blues and purples of salvias and irises. Or watch what they do to liven purple coneflowers (Echinacea). Small plants are great for containers, while taller and bushier varieties can be used as a summer hedge.