Common Name: wormwood
Type: Herbaceous perennial
Zone: 6 to 9
Height: 2.00 to 3.00 feet
Spread: 1.00 to 2.00 feet
Bloom Time: August to October
Bloom Description: Yellow
Sun: Full sun
Water: Dry to medium
Flower: Insignificant, Good Dried
Leaf: Colorful, Fragrant
Tolerate: Rabbit, Deer, Drought, Dry Soil
Best grown in poor to moderately fertile, dry to medium moisture, well-drained soils in full sun. Excellent soil drainage is essential for growing this plant well. Does poorly in moist to wet soils where plants are susceptible to root rot. Plant stems tend to lodge (fall) in the summer, especially if grown in fertile soils and/or part shade. General foliage decline often occurs in high humidity summer climates such as the St. Louis area. Prune plants in spring to control growth, but be careful to leave sufficient numbers of live buds on each stem to facilitate bushy growth. Never prune stems to the ground. Foliage may also be lightly sheared in summer to shape, but avoid pruning in fall. Not reliably winter hardy throughout the St. Louis area where it should be planted in a protected location.
'Powis Castle' is a bushy, woody-based perennial or subshrub which is grown for its aromatic silvery foliage. It rarely flowers. Foliage is finely divided and feathery in appearance. Typically grows in a shrubby mound to 2-3' tall and as wide, but spreads by underground rhizomes and may reach 3-6' wide if not restrained. Essentially evergreen in warm winter climates. It is most likely a hybrid (Artemisia arborescens x Artemisia absinthium). A Royal Horticutural Society of Great Britain Award of Garden Merit plant (1993).
Plants tend to open up in summer. Susceptible to root rot in moist soils, particularly poorly drained ones. Watch for rhizomatous spread.
Silver foliage provides excellent contrast to flowering plants and green foliage in borders and herb gardens. Good selection for areas with poor dry soils.