Dry summer conditions make Artemisia an increasingly popular plant among British gardeners. The drought tolerance and pale foliage of most Artemisia varieties make them outstandingly attractive plants, often with year-round interest. They highlight neighbouring flowers and bring light into borders.
The genus’ interesting scent is as varied as its habitat, which ranges from salt marshes to dry desert to mountain scree. In this country, the plants have green, grey and almost white foliage and are known as mugwort, sagebrush or wormwood. Artemisia is both an ornamental plant and a herb used as everything from a malaria cure to an essential ingredient for the traditional French drink absinthe.
Today, up to 300 of the evergreen, perennial, annual and shrubby plants are available, although many defy easy garden-centre groupings — some are herbs (tarragon being the best-known culinary herb), some alpines, some perennial, some annual and some could be classed as low hedging. Some make good border plants while others do best as edging.
As the doyenne of planting, Gertrude Jekyll, put it: “Between the clumps of Atropa bella-donna are bushes of white lavender, and the whole is carpeted and edged with the white foliage of Artemisia stelleriana, the quite hardy plant that is such a good substitute for the tenderer Cineraria maritima [Senecio cineraria].”
Most Artemisia species thrive in relatively dry conditions — the exceptions include moisture-loving A. lactiflora Award of Garden Merit (AGM) — and dislike shade, wet and cold. Given the right conditions, Artemisia is a tough, fairly low-maintenance plant, although most varieties will be short-lived in slow-draining soil.
Alpines sometimes suffer from root aphids, and blackfly can be a problem for many. Regular trims during the growing season can prevent blackfly and wind rock. The last trim needs to be made in August.
Trimming is also necessary to take off the insignificant yellow/brown flowers produced by some Artemisia — these tend to detract from the plant’s allure. The exception is A. lactiflora AGM, which produces stunning sprays of flowers prized by flower arrangers. Perennials need to be cut back to their base in autumn.
They take from seed (although French tarragon rarely sets seed), greenwood or heel cuttings and, every three years, most plants should be divided in spring or autumn.
What the specialists say
Robert Jacobs, horticultural manager, Waterperry Gardens, Oxfordshire “We didn’t have enough artemisias last year. I think that the drought made this plant especially popular. We raise and sell all our artemisias on site, some as alpines, some as herbs and others as herbaceous.
“A. ‘Powis Castle’ Award of Garden Merit (AGM) shows the versatility of the plant. It’s attractive with silver-grey leaves, and it’s upright and can be used in a herb garden or elsewhere to give structure. It’s semi-evergreen, depending on the winter.
“These grey-leaved plants love a Mediterranean climate, so wet winters can be a problem, and they can start dying off. A classic example of this is the alpine A. schmidtiana ‘Nana’ AGM, which often dies out from the centre in winter. If you give it a light trim in spring, just as it starts to grow, you can sometimes prevent it from dying back.
“We used to grow a lot of Artemisia, but last year we cut down to just A. ludoviciana ‘Valerie Finnis’ AGM, which has a good shape. This year we’re going back to a bigger range, including A. ludoviciana ‘Silver Queen’ AGM.”
Dr John Twibell, National Collection Holder and owner, Elsworth Herbs, Cambridgeshire “Most artemisias are strongly scented, with A. californica having the best scent, in my opinion. Another with a wonderful scent is A. annua. It’s an annual that grows from seed very easily. It has been used by the Chinese for centuries for fevers and malaria, and there are acres of the plant being grown for drug production in Australia and the Far East. It grows to about 1.5m and has fine green leaves.
“Artemisia has a wide range of habitats from A. campestris subsp. maritima, which grows in UK salt marshes, to A. tridentata (also known as Seriphidium tridentatum), which grows in semi-desert locations in the US. The latter has small, grey-silver leaves. You have to have good drainage to grow it in this country but it can survive down to temperatures of –40°C in its native habitat.
“Most artemisias prefer dry conditions but some, like A. campestris subsp. maritima, prefer damp conditions and will grow well in ordinary soil as long as they don’t have much competition.”
Steve Dance, office manager, Burncose Nurseries, Cornwall “They are aromatic and, although the scent isn’t everyone’s cup of tea, some people really like it. We sell them in the herbaceous area of the nursery, although they could be used like dwarf shrubs. They are also valuable as drought-resistant plants and some carry the AGM, which really makes a difference to some people. They’re very good as a foil for other plants or as edging on parterres.”
Species and cultivars
• A. absinthium ‘Lambrook Mist’ Award of Garden Merit (AGM) has delicate white foliage and is a popular garden plant.
• A. absinthium ‘Lambrook Silver’ AGM is a great border plant with a slight green tinge to the mainly white foliage. It provides excellent ground cover with purple/mauve flowers.
• A. alba ‘Canescens’ AGM has very fine, pale blue-green foliage. It grows up to 40cm.
• A. arborescens AGM is a woody evergreen shrub with a tendency to spread. Its silver-blue foliage reaches 1m and, although it is not the tidiest form, it’s a useful plant to add a splash of white to a border or herb garden.
• A. californica has one of the most attractive scents of this genus. It is not often seen as a garden plant but it will grow here on sunny, well-drained sites.
• A. dracunculus is French, rather than Russian, tarragon — and it has the better flavour. It is a prized culinary herb, particularly used in salad dressings and with chicken or fish.
• A. lactiflora AGM is known as white mugwort. Its sprays of creamy white flowers make excellent dried-flower specimens. It looks good in a late-summer border when the flowers emerge over dark green leaves.
• A. ludoviciana ‘Silver Queen’ AGM has relatively large leaves with a hint of green. It grows to 75cm in spread and height.
• A. ludoviciana ‘Valerie Finnis’ AGM has relatively large, white leaves. It grows to a height and spread of 60cm.
• A. ‘Powis Castle’ AGM has fine, pale green to white foliage, making it an attractive woody perennial. It grows to 60cm in height, with a 90cm spread.
• A. schmidtiana AGM is an outstanding ground cover plant with fine, silver-green foliage, which reaches 30cm in height.
• A. schmidtiana ‘Nana’ AGM is particularly neat and looks good all year round.
• A. stelleriana ‘Boughton Silver’ has silver-white foliage. It grows to a height of 15cm with a 40cm spread.