Thunbergia alata Clock vines are cottage garden favorites. They look good in hanging baskets, mixed containers and arbors. The vines can grow to five or six feet high if given good support. Clock vines don't bloom well during high summer heat and humidity, but they will make up for lost time when the weather cools off, blooming well into October. Take cuttings from overwintered plants or sow seeds indoors six to eight weeks before the last frost.
Germination takes two to three weeks, and seedlings grow very slowly.
Wait until the soil has warmed up and night temperatures remain above 50 degrees to transplant outdoors. Place transplants six inches apart about three inches from a support. Supports will be covered quickly after the plants become established. Soil should be moist and high in organic matter. Sunny mornings and afternoon protection are appreciated.