Simply pull or cut them down and compost the remains. Many are actually very tender perennials and grow year-round in USDA Hardiness Zones 9 and warmer. A. 'Joan Loraine' is a new royal purple version. Inside are three jet black seeds, each marked with a perfectly shaped white heart. Alba' is a white variety.
Mature flowers exude a faint honey scent.
10 feet or more. Striking maroon leaves with deeper reddish maroon veins. Ruby Moon' is a popular variety. A white version is also available. Clings with tendrils.