Nearly forty years ago, I planted my first artemisia, a common wormwood (Artemisia absinthium). Its leaves proved so effective as a medicinal tea for stomach complaints and as a moth repellent that this herb moved with us wherever we went, always settling easily into the outskirts of our vegetable gardens in a rough hedge, handy for harvesting.
Only when we stopped moving and I could grow other artemisias did I discover their beauty: their velvety leaves in subtle shades of soft green, gray, silver, and near white; their range of form–from the round cushions of silvermound (A. schmidtiana ‘Nana’) to tall, arching shrublike white mugwort (A. lactiflora), topped in late summer with sprays of cream white flowers–and their bracing aromas. I now grow artemisias in tubs, borders, trimmed hedges, and as single accents. Never again will I relegate them to the sidelines. Artemisias add sparkle to every planting, enhance neighboring bright colors, and create soothing oases during the hot days of summer and fall when they reach their peak of form. Growing artemisias is an herb lover’s dream, uniting utility and beauty.
Members of the daisy family (Compositae), artemisias are distributed throughout the Northern Hemisphere as well as occurring in South Africa and western South America. Most of the herbal forms are shrubby perennials; most flourish in sunny, exposed sites in dry, lean, or ordinary garden soil. Multitudes of tiny hairs protect the foliage from prolonged drought and drying winds, a characteristic that gives the plants their unusual silvery white hues. With the exception of the annual sweet Annie (A. annua), which are easily grown from seed, the herbal artemisias are best obtained as plants, then propagated by division or cuttings.
Valued for centuries as aromatic strewing herbs and bitter-tasting medicinals, artemisias in the West are now used mainly for crafts, especially in wreaths and swags. Several types of wormwood and mugwort still hold an important place in Traditional Chinese Medicine, however.
Common mugwort (A. vulgaris), a weed of waste places, has unsuspected virtues. If its stalks are picked and dried when the flowers are in tiny, tight grayish buds, the otherwise undistinguished, deeply divided green leaves roll over, revealing beautiful soft silver undersides that match their now silvery buds. (Perhaps this transformation from mundane to magnificent was the source of mugwort’s widespread reputation as a charm against evil spirits.) The bitter-tasting flowers and leaves were once used to flavor beer (the common name is believed to allude to midges rather than to beer mugs, however), alleviate digestive and gynecological disorders, and prevent tired feet (put a leaf in each shoe before you set out on a journey). Asians eat the young shoots and leaves to counter the effects of fatty meats, much as Westerners eat sage.
Mugwort is a shrubby 5-foot-tall plant with purplish stems that sprawls as it ages, bearing tiny flowers that turn from yellowish to brown. Confined to the wild landscape, it is kept in bounds by seasonal trimming of its flowering stems for crafts, tussie-mussies (thought to bring luck to travelers), or a soothing footbath with comfrey and mints. After harvesting the stalks, I cut whatever is left nearly to the ground to encourage a mound of fresh foliage.
White mugwort (A. lactiflora), a close relative, is tall and arching, its leaves midgreen and deeply divided with no silver on the reverse. Tiny cream-white flowers with a hawthorn-vanilla scent are borne in loose 2-foot plumes; those of the Guizhou Group show up especially well against their purple stems. In China, white mugwort is used to flavor soups and other dishes.
I treasure white mugwort for its shrubby yet moderate growth (it’s not invasive) and its scented flower sprays in late summer, a time when fresh flowers are most appreciated. Adaptable to moist or dry soil, to sun or part shade, it will grow 6 feet tall in rich soil and may then need staking in windy sites. For shorter, bushier plants that don’t need staking, cut plants back by half in midsummer; blooming will be delayed but just as prolific. Space plants 3 feet apart, or 2 feet if making a hedge. Dig out any excess root growth in the spring to limit the plants’ slow spread.
I plant white mugwort wherever I need a large shrub as an accent. Its foaming feather plumes rise up like a ghostly apparition among red and deep pink monardas and the purple-flowered spikes of anise hyssop. White mugwort flower sprays, fresh or dried, are nice in bouquets, and I add the dried flowers to potpourri.
Although poisonous in large doses, common wormwood (A. absinthium) has been used in minute quantities to treating digestive disorders. A word of caution: wormwood’s strong aroma may cause headaches and a bitter taste if you handle the fresh or dried plant for extended periods.
A shrubby plant that grows from a woody base, wormwood’s stems bear aromatic, deeply divided, velvety gray leaves. Several plants, spaced 2 feet apart and left untrimmed, will form a 3-foot-tall loose hedge, a striking background for purple coneflower in the late summer and fall. As established plants become woody, they can be rejuvenated by clipping back hard in the spring, or new plants may be started from stem cuttings taken in the spring or by simply breaking off and planting clumps of tender new growth with roots attached. ‘Lambrook Silver’, an attractive, compact form that grows 21/2 feet tall, has luxuriant silvery foliage and grayish flowers that combine well with bright monardas. I clip stems in midsummer just as the flowers form, bundle the stems with a rubber band, then hang them to dry in a closet where woolens are stored. The scent repels clothes moths. I also like to combine the dried leaves with tansy, southernwood, and clove oil, then fill net bags with the mixture and slip them among stored clothes and sweaters. In the fall, I cut wormwood plants back to just above their woody base.
Sweet Annie (A. annua) is a 6-foot-tall treelike annual, wide at its base, tapering to a point at its top, with soft, filmy branches of much-divided bright green foliage and numerous tiny golden flowers, all bearing a warm citrus aroma with a camphoraceous note that some find bothersome but others find irresistible. Where summers are long and hot, sweet Annie tends to self-sow, but here in Zone 4, I have to raise seedlings indoors. The seeds germinate readily at 70°F with bottom heat. Sweet Annie needs room to spread at the back of the garden; it’s best planted against a fence to show off its lovely branches.
To use in wreaths and swags, cut the plant down while the leaves are still bright green and the flowers bright gold. Although Chinese sweet Annie has some fragrance when dry, it is more tolerable to those allergic to the familiar, more heavily scented form; its darker stems and small, paler flowers contrast nicely with those of the ordinary type.
Long used to flavor vermouth, Roman wormwood (A. pontica) makes a frothy mound of lacy foliage up to 21/2 feet tall; the richer the soil, the looser the growth, especially if left untrimmed. Its relatively low form, amenable to clipping, suggests its use in knot gardens, where its intricately cut soft gray leaves contrast effectively with green-foliaged herbs such as germander and boxwood. I grow Roman wormwood as a mounding accent near the base of purply rugosa roses and in a border of mixed perennial herbs and flowers against the dark purple spires of the ornamental Salvia nemorosa ‘Ostfriesland’.
Roman wormwood’s invasive underground runners are not a problem because they are easily pulled up. I clip my plants back to the ground in the fall to control their growth and promote fresh foliage in the spring.
With herbal uses similar to those of common wormwood, tree wormwood (A. arborescens) is an upright shrub with finely divided silver-gray fringy foliage that can grow to 3 feet but is dwarfed to 2 feet in a container. Because it’s hardy only in Zones 8 and 9, I grow it in a tub that’s easy to move indoors before the first frost. As insurance, I also pull 4- to 5-inch-long lateral branches with a woody heel off the main stem during the summer; they root at 70°F in four to six weeks. I trim off the small yellow flowers when they appear on the mother plant, for the foliage alone is more striking among the vivid purple spikes of Veronica ‘Sunny Border Blue’. The 2-foot-tall ‘Powis Castle’, thought to be a cross between tree wormwood and common wormwood, is perhaps a zone or two more winter-hardy but still not hardy with me. A more compact plant with bushier foliage, it, too, can be grown to advantage in a tub and propagated the same way as tree wormwood.
If left untrimmed, southernwood, or old man (A. abrotanum), grows into a 3-foot-tall, 3-foot-wide, sprawling, never-fail shrub that I call “poor man’s lavender” for its ability to grow reliably in all but the dampest of garden soils. A favorite in English cottage gardens, its gray-green feathery foliage with a lemony-camphorous scent repels moths and provides aromatic sprigs for country-love posies symbolizing constancy. Folk names such as lad’s love and maiden’s ruin refer to its use in ointments intended to promote beard growth–and by association, male virility. Besides serving as an attractive, shrubby foil for roses, southernwood is invaluable for covering hard soil in an exposed, sunny site where little else will grow. To shape it into a 1-foot-tall mound, clip back stems to 6 inches in the spring and again in early summer. Almost any piece of stem, especially one taken near the base of the plant, will grow to bush size over two seasons when inserted directly into weed-free, well-drained soil. I save my clippings for scenting drawers and closets and for steeping in cider vinegar with other cooling herbs, such as mints, to make a skin freshener.
A citrus-scented form, sometimes offered as ‘Tangerine’ or tree southernwood, is a striking columnar plant that grows to 6 feet tall; it’s well worth looking for in specialty herb nurseries.
The ornamentals include tall cultivars of western mugwort (A. ludoviciana) as well as ground-hugging silvermound (A. schmidtiana ‘Nana’) and beach wormwood (A. stelleriana).
‘Silver King’, the tallest of the western mugworts, widely used in wreaths, has an abundance of narrow leaves growing in tufts on alternate sides of gray stems. The foliage is silvery green on one side and pure silver on the other; upfacing leaves give the plant a light gray cast (it is also called ghost plant). In late summer, just at harvest time, the plant produces panicles of yellowish flowers. If you don’t want to spoil the appearance of the garden by cutting the stems for wreaths, consider starting a cutting garden of ‘Silver King’. A few small starts will quickly form a solid mat of plants. I grow ‘Silver King’ at the back of a mixed border, where it is a cool foil for the colorful bracts of annual clary sage (Salvia viridis) and a contrast in color and form to green mounds of rue (Rutagraveolens). ‘Silver Queen’, which grows to 21/2 feet, and ‘Valerie Finnis’, which reaches 2 feet, are compact variations on the same silvery theme.
I grow silvermound in the corners of timber-edged raised beds. Its silky, shimmering foliage forms 8-by-18-inch mounds that entirely cover the sharp corners, creating a low backdrop for the bluish sprawling foliage of Dianthus plumarius ‘Ballade Strain’, purple-flowered Allium senescens, and tufts of blue fescue. For a stunning silver-on-silver contrast in textures, pair fine-foliaged silvermound with the huge, ruffled, silvery blue leaves of Salvia argentea. To keep the former from collapsing in the center, shear plants in midsummer to encourage fresh growth and divide the mound regularly in the spring.
Beach wormwood, a native artemisia that grows in great sprawling patches on beaches throughout the Northeast, looks like a hardy version of dusty miller (Senecio cineraria). In light soil with sunny exposure, it keeps grass at bay along paths and at the garden’s edge by luxuriantly spreading its thick white, deeply cut leaves over the soil. Gertrude Jekyll grew it to great effect with the blues, purples, and pinks of delphiniums, salvias, and pinks. It may also be grown as a ground cover and in hanging baskets, especially the cultivar ‘Boughton Silver’. Shear plants back when the small yellow flowers appear to promote the growth of fresh foliage.
Jo Ann Gardner, a frequent Herb Companion contributor, lives and works on a backland farm on Cape Breton Island, Nova Scotia, Canada, where she and her husband, Jigs, have been creating gardens of use and delight for nearly three decades. Her latest book is Herbs in Bloom (Timber Press, 1998).