Black-Eyed Susan Vine, Mixed Colors(Thunbergia alata) - Grow Thunbergia seeds for this incredible climber! Commonly called Black-Eyed Susan vine, this tender perennial is evergreen in zones 10 and warmer, and where it is grown as a perennial, it can reach heights of 20 feet. In cooler areas where there are winter frosts, grow Thunbergia vine as an annual, sowing the Thunbergia seeds each spring. This vine brightly displays 1 1/2 inch flowers in multicolor blooms of yellow, white and orange. The simple blooms have 5 petals and surround a brownish purple center. The lush foliage and profuse blooming make this a rewarding plant to grow in any summer landscape. Provide moist, well-drained soil in full sun with some afternoon shade. The Black Eyed Susan vine needs regular watering throughout the summer. Plant seedlings 3 inches away from supports. Netting or strings make good trellis material. Solid fencing or large posts will need trellis material for the vine to climb. Space plants 8 - 12 inches apart. Pinch the tips of young Black-Eyed Susan plants to encourage branching. If grown in a container, Thunbergia can be wintered indoors in a bright, sunny window. How To Grow Thunbergia From Seed: It is recommended to soak the Thunbergia seeds over night in tepid water. Following the soaking, sow Black-eyed Susan vine seeds outdoors after the last frost in prepared seed bed. Or, to get a jump start on the growing season, sow Thunbergia Alata seeds indoors 6 - 8 weeks before outdoor planting. Thunbergia flower seeds germinate better in darkness.