Artemisia 'Powis Castle'
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.