Artemisia, also known as wormwood, grown and used by herbalists for treatment to rid the body of parasites, is also a fabulous perennial for contrast in a garden design. Critters like deer and rabbits leave it alone and it is very maintenance free. The cultivar 'Powis Castle' was introduced in 1972 from the National Trust’s Powis Castle in Wales. Allan M. Armitage considers ‘Powis Castle’ to be “one of the finest plants in cultivation.” 1993 RHS Award of Garden Merit. Evergreen in mild climates.