Seed

• Propagate periwinkle by seed in the early spring, as soon as the soil warms to at least 65 degrees Fahrenheit. Carefully prepare the garden bed before planting your periwinkle seeds. Till 3-inches peat moss, 3-inches leaf mold and 1-inch perlite or coarse horticultural sand into the soil to a depth of 6 inches. Rake the garden bed to a smooth finish and apply 1/2-inch water to lightly moisten the soil. Sprinkle the periwinkle seeds evenly over the surface of the soil. Maintain slightly moistened, but never soggy, soil to encourage the seeds to sprout.