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. Glistening white pointed petals open to reveal a startling bright blue base. Will form colonies that are lovely with Chionodoxa and other Species Tulips.