- You will get 135 Seeds of Black Eyed Susan Vine Flower Seeds. - Sunlight: Full Sun. - Life Cycle: 4 years. - Watering: Medium. - Black Eyed Susan Vine Seeds - Thunbergia alata. - Thunbergia, also known as black-eyed Susan vine or clock vine, is a quick-growing vine boasting many open-faced flowers, usually with dark centers (hence the name "black-eyed Susan"). - Where not struck down by frost it is a perennial, but most climates of the United States grow it as a beautiful annual. The name Thunbergia honors a Swedish botanist named Karl Pehr Thunberg. - Black-eyed Susan vine can grow 6 to 8 feet tall in a season and has rough, hairy leaves. The blooms have 5 distinct petals and are symmetrical. Flower color can be white, yellow, orange, or cream. Most of them have dark centers. - Generally, it grows best in full sun. It needs average, well-drained soil. Plant seedlings 3 inches away from supports. Space plants 5 to 8 inches apart. Pinch the tips to encourage branching. Since thunbergias climb by twining, netting or strings make good trellising materials. They will need a trellis to climb large posts or solid fencing. - Sow seeds outdoors after the last frost or start seedlings indoors 6 to 8 weeks before outdoor planting. Sow seeds outdoors after the last frost or start seedlings indoors 6 to 8 weeks before outdoor planting. Plant the seeds at a depth of 1/4". Fluctuating temps between about 70 degrees/night-85 degrees/day help germination, which occurs in 10-20 days. Use of potting soil during transplant (ready to transplant at 2 sets of true leaves) will help this nutrient hungry plant. - Thunbergias can be used to cover posts, porches, arbors, pergolas, or fences. They also make good container plants. Plants in containers will also bloom over winter in sunny windows.