Black-Eyed Susan Vine

The black-eyed Susan vine (Thunbergia alata) is a tropical perennial that is often grown as an annual flowering vine. It is a frequent sight in hanging baskets at the garden center. This flowering vine is as easy to care for as it is charming. The flowers look daisy-like at a distance, with five overlapping, solid-colored petals surrounding a brownish-purple center tube. The medium green leaves are a little coarse and grow opposite one another—they can be either heart-shaped or have a lance-like arrowhead shape.

This fast-growing vine is best planted as a potted nursery plant in the spring once the soil has warmed. It can extend to 8 feet in one growing season. If grown as a perennial in a warm climate, it will be relatively short-lived, but it colonizes readily by self-seeding. This talent for self-seeding can be a problem, as this plant can be invasive in warmer climates.

Black-Eyed Susan Vine Care

This plant generally does well if planted in any rich, well-draining soil in a sunny location, but it will need some kind of supporting trellis or structure to cling to. These vines will tangle themselves around the nearest support or spill over planter edges. They are perfect for hanging containers and flow just as easily over walls and raised garden beds. A lattice or metal fence makes a good choice for weaving your vines into a living wall, but these plants will clamber over just about anything—from a mailbox pole to an old tree stump.

Black-eyed Susan vines bloom repeatedly from May through fall, and no deadheading (removing spent flowers) is required to keep them in bloom.

Light

You will get the most flowers and the healthiest plants if you grow your black-eyed Susan vines in full sun (at least six hours of direct sunlight on most days). The exception is in hot, dry climates, where growing the plants in partial afternoon shade is recommended.

Soil

Black-eyed Susan vines like a well-draining soil that is rich in organic matter with a fairly neutral soil pH (6.6 to 7.7). It can be helpful to work several inches of compost into the soil before planting.

Water

Although these vines don't like sitting in soggy soil, they also don't like being hot and dry. Aim to keep the soil moderately moist. Mulching around the base of the plants will help to keep the roots cool and moist. Generally speaking these plants will do well with the standard rule: 1 inch of water, rainfall and/or watering per week. Extremely hot dry weather may mean more watering is needed, but on weeks where there is plentiful rainfall, you won't need to water at all. It's best to water again whenever the top inch or so of soil feels dry to the touch.

Temperature and Humidity

Black-eyed Susan vines are reliably perennial only in USDA hardiness zones 10 to 11. Thus, in cooler areas, they are usually grown as annuals (removed from the garden after one growing season). But because black-eyed Susan vines are technically perennials, you can put them in a container and bring them indoors for the winter if you're outside of the recognized hardiness zones. Black-eyed Susan vines grown indoors may flower in the winter if they get ample sun and the temperature doesn't fall below 60 degrees Fahrenheit.

Humidity is usually not an issue for these plants, but they can struggle in very dry conditions, so make sure the soil remains moist.

Fertilizer

Black-eyed Susan vines grow quickly and bloom repeatedly throughout the summer. That means they exert a lot of energy. So they will need a light feeding every four to six weeks with a complete fertilizer to keep them growing well. Plants grown in containers, whether outdoors or as houseplants, should be fed every two to three weeks while the plants are in bloom.