Wormwood is part of the Artemisia family of gray- or silver-leaved plants. It was once used to flavor absinthe and is still used medicinally to repel fleas and moths, and in tonics for upset stomach. Wormwood also makes an attractive border plant with finely divided, silvery leaves that set off red and purple flowers as well as dark green foliage. Wormwood can be used in "night gardens". Night gardens are made up of plants that bloom at night or have light-colored foliage that is easily seen in moon and starlight. Wormwood is a hardy, perennial, shrubby plant that can be invasive without proper pruning, but it needs little care and can last for years.
Prune wormwood in late summer or early fall after the flowers have faded. Remove flower spikes and broken or dead growth.
Apply three to four inches of organic mulch (such as compost or shredded bark or leaves) around the base of the wormwood two to three weeks before the first frost date in your area.
Divide your wormwood plant in the fall if the center has become woody and has started to die. Dig the plant up, getting as much of the root ball as possible.
Use a shovel or pruning shears to divide the outer vigorous growth from the center's dead or dying growth. Replant the sections and discard the center growth.