Thunbergia, a plant native to tropical locations in East Africa, is also known as Black-Eyed Susan Vine or Clockvine. It was named after a Swedish botanist, Carl Peter Thunberg. This twining vine can grow up to 20-feet in frost-free areas and is a favorite of mine. This plant is different than the Black-Eyed Susan flower. It is considered an annual plant and can grow 3 to 8 feet in a single season. The plant is hardy for zones 10 -11.
Traditionally the plant has yellow or orange flowers with a dark center. There are some varieties that are creamy white, light yellow, white, and now even a colorful bi-color. The bi-color photo is from Proven Winners. The flower has 5 overlapping petals. Thunbergia flowers are tubular and the foliage is triangular or an arrowhead-like in shape. The flowers will bloom all summer long.
In the garden, it can be grown as a ground cover or trained to grow on any support such as an arbor or trellis. The plant looks great and is easy to grow in containers or a hanging basket as evidenced by some of these photos. You can even bring the pot indoors to overwinter. If you grow it in a container make sure you have a trellis so it can attach itself. In a hanging basket, let it just trail over the sides. Here is a video showing how Thunbergia can be used in the garden.
Thunbergia grows well in full sun, where it will produce many flowers. If you live in a desert environment, make sure your plant gets shade in the afternoon. The soil should be well-draining. In the summer heat, you will need to water the plant daily because it does not like to be dry but don’t let the plant sit in wet soil. Mulching around the base of the plant will help keep the plant roots cooler and the soil moist.
Once the plant is growing make sure you fertilize it every four to six weeks. If you have your plant in a container you can use a houseplant fertilizer. This will help keep continuous blooms in your garden.
Thunbergia can be grown from seeds or you can get starter plants or even grow it from a cutting. If you live in a colder climate you can start your seeds indoors and then plant them in the ground after the chance of frost has cleared. Since the plant does not like its roots disturbed plant your seeds in a peat moss container so you can just plant it in the ground.
Pests are not really a problem with Thunbergia when grown outdoors. If you bring the plant indoors it might suffer from mites or aphids. If that occurs use an insecticidal soap.
Let us know if you grow this attractive vine!