Thunbergia is a genus of vigorous annual and perennial flowers that includes the clock vine and Black-eyed Susan vine. Thunbergia likes sun, regular watering, and a loam, peat, and sand soil mix. Seeds may be sown indoors for transplanting six weeks before the last frost date, or directly in gardens when danger of frost has passed. This is an aggressive vine that will need support unless it is intended as a ground cover. Fertilizing every six to eight weeks will increase growth and blooms. Thunbergia’s flowers come in white, yellow, orange, apricot, and rose varieties.
Black-eyed Susans (Thunbergia alata) do not like excessive heat or drought conditions. Heat reflected from brick or driveways is especially damaging. Thunbergia grows well in hanging baskets. They have hairy leaves and five symmetrical petals. Petals are delicate - some heart-shaped. These are excellent trellis-, post-, and fence-climbers that can be grown in most regions. In most cases, climate will determine whether they are annuals or perennials.