Select a location providing full sun to get strong and erect stems with large, bright flowers. Stake the plants to protect them from strong winds and to maintain straight spikes and stems. Glads also need good air circulation while growing to reduce insect and disease problems. Planting Figure 1. Glads grow from underground food storage structures called corms.
Corms are solid masses of tissue, rather than layered like true bulbs.
Each year a new corm forms on top of the old one, which shrinks and dies. The new corm forms soon after leaves emerge. The papery husks which form around the corm are actually the bases of old leaves. These husks overlap on the corm, facing the pointed tip. One or more corms may be formed from an old corm.