It’s always wonderful to discover a plant that can solve a multitude of garden challenges while looking gorgeous at the same time. Sometimes referred to as Thunbergia, black eyed Susan vines are used to adorn trellises, attract pollinators, and brighten otherwise drab garden spaces. A native of Africa, flowers grown in frost-free regions will behave as a short-lived perennial. However, their quick growth makes them an ideal candidate for annual beds, as well.
Black-eyed Susan vine is commonly grown in the Midwest as a seasonal annual to provide color in a vertical setting. Because it grows and flowers relatively quickly it is often used as an annual ornamental garden plant in cooler areas. This old-fashioned beauty grows extremely quickly and is very easy to care for, making it a favorite in the garden every year.
Tangerine Slice A-Peel® black-eyed Susan vine (Thunbergia alata). Photo by Proven Winners.
Quick Black Eyed Susan Vine Facts
Here are some quick facts about the Black Eyed Susan Vine:
- Botanical name - Thunbergia alata
- Height - 3-8 ft (1.0-2.4 m)
- Spread - 3-6 ft (1.0-1.8 m)
- Sun exposure - Full Sun
- Soil requirements - Neutral, Slightly Acidic, Slightly Alkaline
- Hardiness zones - USDA Zones 10-11, Annual Elsewhere
- When to plant - Spring
Stems and leaves are green, and flowers are usually a deep yellow, white, or orange with black centers. There are also red, salmon, and ivory flowered varieties. Black eyed Susan is a fast-growing vine that needs a vertical stand or trellis to support the plant. The vines twine around themselves and anchor the plant to vertical structures.
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Where to Plant
These plants grow best in a sunny site sheltered from strong winds and drafts. Thunbergia alata grows best in rich, moist soil in full sun. It tolerates partial shade but flowering may be reduced.
In smaller yards, this fast-growing tender perennial is a great space-saver because it enthusiastically twines up trellises, fences, arbors, and other supports to take advantage of underutilized vertical space. Need to quickly fill in bare spots in your garden? And if you’re simply looking for an easy-care flower that will fill your garden with brilliant color from summer well into fall, black-eyed Susan vine is the perfect choice.
When and How to Plant Black Eyed Susan Vine
For the earliest flowers, start seeds indoors 6 to 8 weeks before your last frost date in spring. You can also start plants from seed sown directly in the garden after the last frost. If growing from seeds, plant them about 1/2 inch deep, covering them with a fine layer of soil. Don’t worry if the seedlings take awhile to emerge.
Growing black eyed Susan vine from seed is a quick and easy way to add seasonal beauty to the home landscape. Seeds are best sown in spring. Though they can be started indoors, most prefer to sow them directly into the garden. This can be done after all chances of frost have passed and the soil has warmed sufficiently. Black eyed Susan vine seedlings should begin to emerge in as little as 5-7 days from planting. Vines will start to heighten within the first few weeks, requiring support to continue their climb.
Light Conditions
When it comes to black eyed Susan vine, plants will grow best under full-sun conditions. This means that they should receive at least 6-8 hours of direct light each day. Vines can be grown in beds that are shaded, though they won't grow as long or flower as profusely.
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Soil
Prefers moist, well-drained, fertile soil that is rich in organic matter. Black eyed Susan vines grow best in warm, well-amended beds. The plants are adapted to a wide range of soil conditions, including those that are neutral, slightly acidic, or slightly alkaline. Finished compost and other amendments can be added at planting time, as needed, according to the specific needs of one’s own space. Good drainage is essential, with vines thriving where soils remain consistently moist.
Watering Needs
Like most tropical plants, Thunbergia alata does not tolerate drought. Water regularly throughout the growing season to keep the soil evenly moist but not soggy. Plants grown in containers may need more frequent watering. Routine watering will aid in growth as well as the production of flowers. Make sure to saturate plants deeply, at their root zone. Avoid overwatering, as vines won't tolerate beds that are excessively wet.
Temperature and Humidity
Black eyed Susan vines thrive where conditions remain warm. Before planting outdoors, make sure both day- and night-time temperatures remain consistently above 50F (10C). Soils should also have been allowed to warm sufficiently, to at least 60F (15C). Though adaptable to a wide range of humidity, plants may struggle where weather is especially dry.
Amendments and Fertilizer
In the garden, the application of a controlled-release fertilizer at planting time is usually sufficient to keep plants thriving. Container-grown plants will also benefit from the use of a controlled-release fertilizer while plants are in bloom; follow directions on the label.
Though optional, applications of a well-balanced fertilizer can be used to promote bloom. Vines should be fed early, before the production of buds. Routine fertilization can continue every 4-6 weeks. You should avoid over-feeding, though, as it can result in excessive leafy growth and diminished flowering.
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Supporting and Training Black Eyed Susan Vine
Black eyed Susan vines climb by twining. This means that the best supports for the plants are those which it is able to spiral up. Examples of such supports include various types of garden twine, trellises, arbors, and stakes. As plants can reach impressive heights, supports should be secured well and able to easily hold the weight of mature vines.
If you want your black-eyed Susan vines to climb a support, they will need a little coaxing to get started. You can secure young shoots to the base of the support with gardener’s wire or coated twist ties until the plant has secured itself. As the vines grow, any stray or wayward shoots can be carefully twisted around the support.
Pruning and Deadheading
Light pruning can be done as needed throughout the growing season to help shape plants and manage their size. Black eyed Susan vines are relatively carefree and require only little pruning. In fact they'll continue blooming throughout the season without the need for deadheading. Though large plants can be trimmed or pruned to control their size, it is not needed to promote new growth or the production of flowers.
BLACK EYED SUSAN VINE Growing and Care Tips! (Thunbergia alata)
Overwintering Indoors
In climates where black-eyed Susan vines aren’t hardy, potted plants can be moved indoors in late fall (or as soon as nighttime temperatures fall below 50 degrees F) and grown in a sunny window as a houseplant.
How to Propagate a Black Eyed Susan Vine
You can grow a black eyed Susan vine from seed. Growing a black eyed Susan vine from cuttings is easier. Overwinter the plant by cutting several inches from a terminal end of a healthy plant. Remove the bottom leaves and place in a glass of water to root. Change the water every couple of days. Once you have thick roots, plant the start in potting soil in a pot with good drainage. Grow the plant until spring and then transplant outdoors when temperatures warm up and there is no possibility of frost.
Problems, Pests, & Diseases
Black eyed Susan vines only seldom have issues with pests or disease. That doesn't mean they're problem free, though. Powdery mildew is most common, but can be controlled by the removal of infected leaves and/or use of various treatments. Watch for pests like whitefly, scale or mites and combat with horticultural soap or neem oil.
Best Black Eyed Susan Vine Varieties
- ‘African Sunset’ Black Eyed Susan Vine - Consisting of yellow-blush blooms, ‘African Sunset’ is praised for its delightful color and unyielding ability to cover obelisks and trellises. This is an excellent black eyed Susan vine for containers.
- ‘Bright Eyes’ Black Eyed Susan Vine - ‘Bright Eyes’ is sure to make a statement. With pristine white flowers, this cultivar stands out among the most unique types of black eyed Susan vines available to home gardeners. Its high contrast makes it an attractive addition to mixed borders and hanging baskets.
- ‘Sunny Susy Amber Stripes’ Black Eyed Susan Vine - Like most varieties, ‘Sunny Susy Amber Stripes’ offers an array of brilliantly-colored flowers. Lush foliage and red-orange blooms make for an attractive groundcover that is well-suited to a warm garden palette.
- ‘Superstar Orange’ Black Eyed Susan Vine - Producing among the largest blooms of any variety, orange flowers put on a vibrant display throughout summer. ‘Superstar Orange’ is an exceptionally popular choice for pollinator gardens and for those hoping to attract hummingbirds.
Frequently Asked Questions
Here are some frequently asked questions about the Black Eyed Susan Vine:
Is Black Eyed Susan Vine a Perennial?
Within its hardiness range, black eyed Susan vine can be grown as a short-lived perennial. However, the plant is commonly treated as an annual outside of these frost-free regions. This is thanks to the plant’s habit of rapid growth and ability to flower from seed within a single season.
Is Black Eyed Susan Vine Poisonous?
Though little information is available online in regards to whether or not the vine is considered poisonous, plants do contain various toxins. Mild toxicity has been reported in some livestock that have consumed the plant, therefore, care should be taken in gardens frequented by children, pets, and other special populations.
