Planting and caring for black-eyed Susanne

Black-eyed Susanne belongs to the acanthus family (Acanthaceae) and can be found in its homeland as a perennial climbing plant. Botanically it is called Thunbergia alata and for many years was known mainly as a climbing plant with orange or yellow flowers. Through breeding and selection, variants with pink, red or white flowers are now also available. Well Thunbergia alata can be preferred from seeds. You should start sowing in January. It’s quicker if you buy Black-eyed Susanne in May and plant them out straight away. Delighted with a multitude of colorful flowersthe vigorous climber all summer long. Black-eyed Susanne is not hardy.

Useful information Location Planting Care Watering Fertilizing Pests & Diseases FAQ

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Worth knowing about the black-eyed Susanne

Botanical name: Thunbergia alata
Other names: black susan, one-eyed susan, brown-eyed susan, black-eyed susan
Use: annual climbing plant, summer privacy screen, also possible in traffic lights, bee pasture
Origin: tropical Africa, Madagascar
Flower colors: orange, white, red, pink, yellow (with a dark center or one colour)
Flowering period: April to October
Special features: Thunbergia alata is a so-called left winder. The climbing plant twines counter-clockwise upwards. Without a climbing aid, black-eyed Susanne tends to grow hanging.

In which location does black-eyed Susanne feel most comfortable?

Plant Black-Eyed Susanne in a warm, full-sun spot outdoors from mid-May. Planting out in the ground is ideal, but growing in pots is also possible. When planting out, make sure that the soil is rich in humus and loose. Locations that tend to waterlogging or soil that is too light are unfavourable. In sites with heavy, loamy soil, good soil preparation before planting is important. Use gravel and sand for good drainage. With sandy soil you should work with plenty of potting soil. So that the climbing plant grows optimallycan develop, the use of climbing aids is necessary. The summer flowers can also be planted on balcony railings, fences and privacy screens.

How do I plant my Black Susanne correctly?

The annual climbing plant develops optimally on the balcony or terrace with an even water supply, regular fertilization and a sufficiently large volume of soil. Therefore, repotting is necessary immediately after purchase. Plant the one-eyed Susanne in a larger container or directly in the bed in the garden. Ideal are plantings in front of fences or privacy walls, where the climbing plants can hold on and wind up

Planting Black-eyed Susanne in the ground:

  • Place the pot in a vessel filled with water and submerge the root ball until no more air bubbles rise. This ensures that the plant is sufficiently watered.
  • Dig a planting hole twice the size and depth of the climber’s root ball.
  • Fill the planting hole with a thin layer of drainage.
  • Repot your black-eyed Susanne and place it in the planting hole.
  • Fill the space between the root ball and the planting hole with potting soil. The pH of the soil should be between 6 and 7.5.
  • Press the soil lightly so that the so-called ground contact is created.

Finally, water the new planting with 3 to 5 liters of water.

Planting Black-eyed Susanne in a vessel:

  • Choose a jar with a drainage hole. Pots without a hole are unsuitable.
  • Pay attention to the volume. The larger the volume of soil, the better the climbing plant will develop. As a guideline, we recommend containers with at least 10 to 15 liters.
  • Place the pot in a container filled with water and submerge the root ball until no more air bubbles rise. This ensures that the plant is sufficiently watered.
  • Put a thin layer of expanded clay on the bottom of the pot for drainage.
  • Fill the pot halfway with potting soil and place the well-watered summer flower in the pot.
  • Fill the space between the root ball and the planting hole with potting soil.
  • Finally , pour in 3 to 5 liters of water

How do I properly care for my black-eyed Susanne?

Thunbergia alata are easy-care and uncomplicated plants. They are also the ideal plants for children, as they grow quickly in summer, bloom profusely and require little attention. It is important that you provide the climbing plant with a climbing aid in good time. This can be a tomato spiral stick, a trellis, wires, a balcony railing, string or similar. A cut is not necessary, but can be done for optical reasons. You can remove faded flowers, but it is not absolutely necessary. By cleaning out, you promote the willingness to flower and seed formation is prevented.

How do I water my black-eyed Susanne correctly?

An even water supply and a sunny location are important for growth and flowering. Immediately after planting, the water requirement is still low. Watering every 2 to 3 days is usually sufficient. If the plant has developed magnificently and reached a height of over 2 meters, daily watering may be necessary on hot days. However, the water requirement depends on the location, size of the plant, the volume of soil and the temperature. Specimens planted out in the garden have a better chance of getting water. Therefore, the effort for care is slightly lower here than with culture in pots.

Our gardening tip: Black-eyed Suanne suffers from waterlogging and easily suffers root damage. After extreme drought, growth may be stunted or the flowers may fall.

How do I fertilize my Thunbergia alata correctly?

Specimens planted in the ground receive a dose of organic natural fertilizer when planting. This purely organic special fertilizer is slowly becoming available and thus ensures an optimal supply of nutrients for months. This fertilizer promotes soil life and the formation of humus is stimulated. Continuous fertilizing with liquid flower fertilizer containing guano is recommended as a climbing plant in a container. In addition to the most important nutrients, this special fertilizer contains revitalizing humic substances, which particularly promote the formation of flowers.

Our gardening tip: You can recognize a lack of fertilizer by the fact that the foliage of the black-eyed Susan becomes lighter and the plant has less growth.

What pests and diseases can black-eyed Susan get?

With optimal conditions and good care, the climbing plants are robust and hardly susceptible. However, the following pests can occur:


Black-eyed Susans are more susceptible to aphid infestation, especially during periods of less light, low humidity and restricted growth. Rinse the plants thoroughly with water at the first infestation — this measure usually helps. Natural plant strengtheners help the plant grow stronger tissue that is less likely to be attacked by sucking insects.

spider mites

Especially plants with often dry root balls are attacked by spider mites. The affected leaves have silvery dots on the upper side and webs are visible on the underside of the leaves. It is usually sufficient to hose down Black-eyed Susanne with a hose and treat it with a plant strengthener. These organic active agents contain natural plant extracts that vitalize the plant and make care easy.

Are you looking for more information about pests and diseases or do you have questions about a plant problem? Our plant doctors will be happy to help you – in person and online!

FAQ — Frequently asked questions about Black-Eyed Susan

How can black-eyed Susanne breed?

The popular climbing plants can easily be propagated by sowing. Start sowing in January or February. This gives you strong plants that bloom profusely. Propagation by cuttings is also possible. The best time to do this is late summer. Use a knife to take cuttings from growing plants. The head cuttings root optimally in propagation trays or in a propagation set with a transparent cover.

Why is Black-eyed Susan not blooming?

Missing flowers in Thunbergia alata are usually the result of a wrong location or care errors. If the location is too shady or drafty, the black-eyed Susanne may only bloom a little.

Can you hibernate Black-eyed Susanne?

The climbing plant is usually an annual summer flower, as overwintering is somewhat problematic. For hibernation, the black-eyed Susanne is placed in a bright and frost-free place from October. A pruning before clearing is recommended. The plant is shortened by half. The ideal temperature for wintering is 10 °C. During the winter, watering is sparing and fertilization does not take place.

Can Black-eyed Susan be kept as a hanging plant?

Without climbing aid, the shoots of Thunbergia alata also grow downwards. Planting in a pot and a location on a parapet or a flower stool is ideal.

Is black-eyed Susan poisonous?

The popular climbing plant is not poisonous. The flowers are sometimes used as an edible decoration.

How tall will black-eyed Susanne get?

In ideal conditions, the annual climber can grow up to 2 meters high.

What insects is black-eyed susan useful for?

Thunbergia alata serves as a nutrient plant, especially for long-nosed garden bumblebees and brimstone butterflies.

Do black-eyed Susanne have to be pinched?

When growing your own, it is important that you prune the young plants several times. As a result, the climbing plants grow bushy and develop many side shoots. To do this, regularly remove the shoot tips.

What can be the reason if black-eyed Susanne loses a lot of leaves?

Too much water or a pest infestation is usually responsible for leaf fall on Thunbergia alata.

What colors are there in black-eyed Susanne?

Classically, the color combination of orange with a brown/black center was typical of Thunbergia alata. Breeding and selection resulted in interesting colors. Black-eyed Susanne is now also available in pink, white and lemon yellow, sometimes without an eye.

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