How to Grow a Purple Periwinkle Plant

Start periwinkle seeds indoors eight to 10 weeks prior to the final frost. Fill each section of a cell flat with a starter potting soil mix and sow the seeds ¼ inch deep. Spray the soil with water to thoroughly moisten. Place in an area with low light that is around 60 to 70 degrees Fahrenheit, such as a basement. Keep the soil moist.

Transplant the periwinkle seedlings into the ground after danger of frost has passed. Choose an area that is in partial shade. The foliage of the purple periwinkle may burn if grown in full sun, but requires some sunlight in order to flower. Partial shade also promotes a richer foliage color.

Plant the purple periwinkle in a soil that is rich in organic matter and drains well. A soil with a pH of 6.0 to 8.0 is ideal.

Dig a hole using a hand spade that is as wide and deep as a cell flat section. Gently remove a seedling, soil and all, from a cell flat section and place it into the hole so that the seedling is growing at ground level. Fill in the hole with soil and tamp lightly. Water to moisten the soil.

Plant all of the seedlings in the same manner. Space the periwinkle plants 12 to 18 inches apart.

Purple periwinkle is fairly drought resistant and can also tolerate too much rain if it is in a well draining soil. Water to supplement rainfall to keep the soil moist.

Fertilize the periwinkle in the spring with a complete fertilizer such as 10-10-10. Clemson Cooperative Extension suggests applying the fertilizer at a rate of 6 to 8 pounds per 1,000 square feet.