Artemisia 'Powis Castle'

Artemisia Powis Castle (left) with Plectranthus argentatus

This lovely silver-leaved plant (ht 60-100 cm) is one of the best specimens in this genus, some of which can be invasive. It is thought to be a cross between Artemisia absinthium and Artemisia arborescens. It has highly dissected, silky, aromatic leaves and should have been an asset in a sunny border, but I always found it rather shapeless and lank: it never made the dense mound of foliage in the middle of a border that I saw in English gardening books, and I always seemed to be cutting it back to try to make it more dense.

A breakthrough came when I decided to grow it over the edge of a sunny retaining wall, giving it good drainage and allowing it to not be hemmed in by other plants. It looks so much better in this spot, flopping forward in a good way. I have also taken to tip pruning it to encourage a denser form, and this has helped. I enjoy pairing it with the broad silver leaves of Plectranthus argentatus or with compact Salvia shrubs. It has yellow-tinged flowers in summer, but its main attraction is its foliage. Cut it back in late winter. It strikes easily from cuttings taken in spring or autumn. It gets woody after a few years, and should then be replaced by a young plant. Cut stems are useful in floral arrangements.