Thunbergia Plant Care

Looking for another beautiful plant to hang in your hanging baskets? Then, this Thunbergia plant is the perfect choice for you! This is a genus of 100 plants native to tropical Africa and Australia that produces vast, funnel-shaped flowers with dark centers (or “black eyes”) and heart-shaped leaves in hues of yellow, white, orange, and blue.

At a distance, the flowers resemble daisies, with five overlapping solid-colored petals surrounding a brownish-purple central tube. The medium green leaves are coarse and grow in opposing directions, either heart-shaped or with a lance-like pointy shape.

Thunbergia alata is sometimes known as the Black-eyed Susan vine. It’s a tropical evergreen twining vine that can reach a height of 20 feet in frost-free zones. And grows 3-8′ tall in a single season as an annual.

Want to add these Black-eyed Susan vines to your garden? Then, let’s learn how to take care of it first. Read below to find out more.

Thunbergia Plant Care Basics


Before anything else, we’ve provided an overview of the plant for you to know it better.

Botanical name: Thunbergia grandiflora

Another name: Black-eyed Susan vine, Bengal trumpet vine, Clock vine, Bright eyes

Plant type: Perennial flowering vine (usually grown as an annual)

Exposure to sunlight: Partial shade to full sun

Soil type: Well-draining

Color: Red, white, orange, or yellow flowers

Water: Average

Favorable climate: Tropical

Preferable fertilizer: Liquid fertilizer

Propagation: Seeds

Toxicity warning: Non-toxic

Status: Rare

Height: 5 meters in warmer zones

Origin: Africa and Australia

Already know this Black-eyed Susan vine? Let’s now dig into the essential tips in taking care of these indoor plants. Enjoy!!

Recommended Potting mix

When it comes to the potting mix of the Thunbergia vine, it is essential to keep nutritious and well-drained soils. The soil pH of the Black-eyed Susan vine should be slightly acidic to slightly alkaline. The plant, on the other hand, will wilt if the soil is too dry.

The addition of compost to the soil delivers much-needed nutrients to the soil. Compost also aids in obtaining the ideal pH level required by these plants.

Pro tip: If growing in a hanging basket, top-rated potting soil is recommended. You may also try 1 part humus earth, 1/2 part coarse-grained sand or perlite, and 1 part sod land.


Thunbergia light requirement

If you grow your Black-eyed Susan vines in full sun, you’ll receive the most flowers and the healthiest plants. And your plants should get at least six hours of direct sunlight on most days. Although the Black-eyed Susan vine can tolerate some shade, flowering may be affected.

The plant will continue to bloom as long as it is exposed to enough sunlight and the temperature does not drop below 60 degrees Fahrenheit.

Pro tip: It is best to grow the plants in the afternoon shade in dry or hot locations because they do not perform well when exposed to direct sunlight.

Watering Needs

Thunbergia indoors doesn’t like wet soil, but they also don’t like it when it’s dry. Once a week is ideal in maintaining their moisture. Throughout the growing season, the plants demand regular and deep watering.

Medium moisture, but not wetness, should be maintained in the soil. Shredded leaves or organic mulch are also ideal for these annual plants. This type of mulch gives the bed a natural appearance while also enriching the soil.

Pro tip: Containerized plants should never be allowed to dry out.

Recommended Temperature & Humidity

In the summer, the average room temperature is 70 degrees Fahrenheit (21.1 degrees Celsius). In the winter, the ideal temperature is 47.2 – 53.6- degrees Fahrenheit (8. 3 – 12.2 degrees Celsius). They are commonly grown as annuals in cooler climates.

Because black-eyed Susan vines are actually perennials, which means they come back year after year if you live outside of their hardiness zones, you can put them in a container and bring them inside for the winter.

plant humidity requirement

Although humidity usually is not an issue for these plants, they might suffer in arid conditions, so keep the soil moist. You can increase the humidity by misting the plant, groupings plants together, and having a humidifier close to the plant.

Necessary Fertilizer

Every plant requires fertilizer since it contains additional nutrients that plants need. By doing this, the Black-eyed Susan vines grow swiftly and frequently flower all summer long. You can fertilize your plant using liquid fertilizer every two weeks.

Fertilizer with a higher potassium content is beneficial from the start of budding. Keep in mind that excessive fertilization might result in excessive growth and fewer blooms.


Another thing about this climbing Black-eyed Susan is that it is easy to propagate via seeds. Although it might take longer, it can grow well! Seeds can be pricey because the seed of this rare plant is hard to come by.

Here’s what you will do: 

You can start seed inside six to eight weeks before your expected last frost date or direct-seed in the garden once the threat of frost has passed. Before planting, soak the vast, hard seeds in water for a day or two. Make sure the seeds get enough moisture and that the soil doesn’t dry up. Keep the soil moist for at least 9-14 days until you see the roots sprouting from the seeds.

Pro tip: Early spring or the end of winter are the best times to sow seeds for new plants, but sow them in late spring if you want to witness rapid growth.

Growth Zone

plant growth zone map

Thunbergia species are fragile evergreen perennials in the acanthus family (Acanthaceae) hardy in zones 9 and 10. It is native to tropical East Africa and eastern South Africa.

Potting and Pruning

Select a deep and broad container enough to accommodate root development and growth and a proportional balance between the fully mature plant and the container. Plus, these beauties look good when put in hanging baskets. Always put in mind that any container should have proper drainage.

You can prune it whenever you want because it grows too much in hot locations, and you have to prune it from above to keep it in line. We also need to cut them to a length that looks beautiful to maintain them healthy.

Thunbergia Varieties and Similar Plants

These Thunbergia plants also have similar plants and varieties. And I know if you know these beauties, you also want them in your collection! 

Here are some of them:

  • Black-eyed Susan Indian Summer

Because these plants do not live for a long time, they are sometimes known as short-lived perennials. These plants can reach a height of 5 to 8 inches, and they can even reach a height of more than 8 inches. From the top to the right, the plant grows. They have a vivid yellow color with a brown core, making your landscape look even more gorgeous.

  • Black-eyed Susan Goldsturm

This plant resembles a black-eyed Susan, which has yellow flowers and a black spot in the middle. When these plants blossom, they naturally attract neighboring butterflies. If you cultivate this in your garden, it will spread slowly up to a maximum of 14-18 inches. Its height ranges from 5 to 11 inches and can occasionally exceed 12 inches.

  • Black-eyed Susan Toto

The plant is noted for its beauty and ease of care. Its flower is a bright golden yellow color that matures to the dark brown color in the middle. This plant can grow to a height of 4 to 12 inches and spread to a width of 16 to 18 inches. Because this plant grows and takes up a lot of areas, it’s best to plant it in the ground rather than in a container.

Thunbergia Plant Diseases & Pests

The black-eyed Susan vine is susceptible to plant scale, whiteflies, and spider mites when treated as an indoor plant. In locations where the weather is hot, this is a significant issue. Insecticidal soap can solve the problem immediately. Also, keep an eye out for diseases that cause stem and leaf damage. Indoors, where the heat is dry, black-eyed Susan vines do not thrive.

But if it is appropriately taken care of, plants should thrive as long as they get enough water, sunlight, and air circulation. Plus, problems are rare to find if the condition is ideal.

Frequently Asked Questions

Although it is often planted annually, it has been found to overwinter in temperate areas during hot winters. Because black-eyed Susan vines are perennial, you can pot one up and bring it inside for the winter. When you’re done, you’ll probably want to trim it down to a more manageable size.

When it comes to when and where it blooms, the Black-Eyed Susan vine is extremely finicky. The most typical reason for your Black-Eyed Susan vine’s failure to blossom is excessive heat. Protect the plant from burning heat by providing it with a cool, sunny environment.

As spent blooms fade, deadhead or pluck help them encourage new bloom production. Thunbergia can be pruned for shape and size in the fall or early spring in climates that grow as a perennial. You can pull the plant and roots from the soil in cooler locations where it grows annually, pot it up for winter in a greenhouse, or simply discard the plant

You can now have your own Thunbergia plant here at Plantly! Yes! Here we offer faster transactions online. What are you waiting for? Hit the message button now!

Whether you want to buy, sell or simply reach out to other plant enthusiasts, Plantly is the right place to be!

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