Black-eyed Susan (Thunbergia alata) is known as a long-flowering, fast-growing creeper. The perennial vine has many stems, dotted with heart-shaped leaves. The flowers are trumpet shaped and are usually a dark yellow color with black centers. Black-eyed Susan will bloom all year long if the night temperatures stay above 60 degrees Fahrenheit and they get sun during the winter. If not, the vine blooms in the summer. Black-eyed Susans are great for use in hanging baskets and for climbing on trellises.
Plant black-eyed Susans in the full sun. It's OK if the planting bed is in the shade in the afternoon, but it should have full sun in the morning for optimal growth. If you notice the plant is droopy and not flourishing, try changing its location to a sunnier spot.
Water black-eyed Susan vines regularly to keep the soil moist. The plant doesn't cope well with drought. Add water whenever the top inch of soil feels dry to the touch.
Fertilize twice a month with a balanced fertilizer. It should have an equal ratio of nitrogen-phosphorus and potassium, such as 20-20-20. Dilute the fertilizer to half the strength the manufacturer recommends because the flower prefers moderate to light fertilization.
Trim black-eyed Susan vines occasionally to keep the plant from looking stringy. The vines can grow up to 5 or 6 feet long if pruned regularly. It will also encourage more blooms to grow.
Cut off unproductive stems at their bases where they meet the soil. Trim other stems back to promote blooms by cutting on an angle, just outside a bud.