Periwinkle Ground Cover Propagation

Division

• Dividing an established periwinkle plant is the simplest way to start a new plant. Additionally, dividing the plant every few years keeps the plant healthy and vibrant. Although you can divide periwinkle in spring or autumn, the latter is best because the plants have plenty of time to establish roots before hot weather. Dividing periwinkle involves digging deeply to remove the plant along with as many roots as possible. The clump is then planted into a prepared location. If the clump is large, you can cut a small clump from the main clump with a sharp spade or shovel.

Stem Cuttings

• Periwinkle cuttings taken from young, actively growing plants in late spring or summer root best. Look for stems that are firm but flexible. Plant the cuttings in a pot filled with a free-draining medium such as half peat moss and either fine bark or perlite. Be sure the pot has a drainage hole to prevent rot. Dipping the stems in rooting hormone isn't required but the hormone speeds rooting. Once the cuttings are planted, a plastic bag keeps the stems warm and moist until new growth appears, usually in three to four weeks. Low light is best because bright, intense light may scorch the tender cuttings. When new growth is apparent, remove the plastic and move the plants into bright sunlight. The new periwinkle plants are ready to transplant outdoors after all danger of frost has passed the following spring.

Layering

• Layering periwinkle is a simple process that takes advantage of the plant's natural growth habit of rooting where the stems touch the soil. Wherever the stems take root, you can cut the newly rooted section from the parent plant. Dig the rooted plant and move it to its new location. If the periwinkle stems don't root naturally, pin a stem to the soil with a piece of bent wire, then cover the pinned spot with soil. Keep the soil moist and pinned spot will soon develop new roots. Layer periwinkle any time the plant is actively growing.

Seed

• Growing periwinkle from seeds challenges even experienced gardeners. Starting seeds indoors is critical because you can control the environment and avoid cool temperatures and excessive humidity. The seeds require a dark environment until germination, so after planting, the seed tray is usually covered with a black plastic bag. A heating mat set at 77 degrees Fahrenheit ensures that more seeds successfully germinate. Once the seeds germinate, place the tray in bright sunlight in a room where the temperature is maintained at about 70 degrees F. Because periwinkle is drought-tolerant, the potting mixture should be kept just slightly moist. Plant the new periwinkle outdoors after the temperature is consistently above 65 degrees F in spring.