Foxglove (Digitalis purpurea) is that beautiful but deadly poisonous plant also called digitalis. Foxglove is the source of the drug digitalis, which doctors use to regulate the heart beat. This biennial grows from 60 cm to 1.2 m (2 to 4 feet) tall and blooms from June to September.
Although you can deadhead foxglove -- remove dead flowers -- at any time during the season, it should be pruned in late summer, if at all, after the last bloom.
Deadhead the foxglove to remove dead and dying flowers, unless you are saving seeds. Then, cut out any brown foliage and stems. This stimulates the plant to produce new foliage. Because the plant lives for only two years, and foxglove blooms only in the second year, most gardeners leave the last few flower stalks on the plant in the autumn, where they can reseed for the following season.
Bypass pruning shears are the ideal tool for pruning foxgloves. Make sure they are clean and sharp.