How to Grow Annual Vinca from Seed

Annual vinca is a medium sized flowering plant that does well in flowerbeds, as edgings, and in containers. Annual vinca, sometimes called Madagascar periwinkle, is not to be confused with the perennial vinca, which is a creeping ground cover. This plant begins flowering in June, but since it takes a long time for the plants to bloom the seeds should be started indoors during the winter.

Appearance and Growth Habit of Annual Vinca

The flowers of annual vinca are usually pink or white with red or white spots in the center. Some liken this plant to large impatiens, yet it takes heat and sun better than impatiens do. The leaves of annual vinca are slim, oval and medium to dark green. The plant grows about one to two feet tall and the spread is about the same. Annual vinca is sometimes confused with perennial vinca, which has a different growth habit. Perennial vinca is a spreading vine-like ground cover that bears small blue flowers. Annual vinca grows upright.

Sowing the Annual Vinca Seeds

Growing annual vinca from seed takes some planning. The seeds need to be started indoors about ten to twelve weeks before the last frost date in your area. For gardeners in many areas of the United States, this means planting them between the middle of January and the end of February. If the seeds are not yet available in local garden centers purchase them from a seed catalog.

First, prepare the container. It can be a seed starting tray or even an old margarine container. Make sure it has holes for drainage punched in the bottom. Fill this container about ® of the way with soil. Use an atomizer to gently spray water on the soil and dampen it. To sow the vinca seeds, scatter them over the top of the soil and then add ¼” of dirt on top of it.

Keeping the seeds moist, but not soaking is another important step. After planting the seeds, spray the surface of the soil with the atomizer. Gently moisten it. Next, cover the pot or tray with a plastic bag or plastic wrap. It should not be too tight or too loose. The plastic will promote a warm, moist environment for the vinca seeds.

After the annual vinca seeds are planted, keep them in a sunny warm spot. Set the plastic covered container in the sun when the vinca seedlings emerge. The air temperature around the seedlings should be at least 70 degrees.

Transplanting and Caring for the Annual Vinca seedlings

The annual vinca seedlings should emerge in about one to two weeks. Transplant the vinca seedlings to the 2″ pots when they have at least three to four ‚”true” leaves. This does not include the ‚”seed” leaves, which are the first two to emerge, but the sets of leaves that grow after that. The seed leaves will be small and round while the ‚”true” vinca leaves won’t be. Transplant only the strongest seedlings to the pots. Continue to grow them in a warm, sunny area and give them adequate moisture.

Annual vinca can be transplanted outdoors after all danger of frost has passed. These plants do not like cool, wet spring weather and the soil needs to be fully warm and dry. Vincas grow best in average soil and are heat and drought tolerant. Space them about six to twelve inches apart, depending on how dense you want the planting to be. Water the vinca plants only when conditions are dry. These plants do not like excessive water. To feed annual vinca, fertilize the plants with a 10-4-3 fertilizer about once a month during the growing season. Annual vinca may be challenging to grow from seed, but once it is established in the garden it can reseed itself. This plant can also be propagated from cuttings.

Resources

The Gardener’s Network: How to Grow Vinca or Periwinkle Plants

Clemson University Cooperative Extension

Iowa State University Extension: Annual Vinca and Common Periwinkle