Vinca Flower Temperature. If you want a pop of color that lasts from spring all the way to the fall annual vinca Catharanthus roseus is the plant for you. Pull up any weeds growing.
Periwinkle grows 3 to 6 inches tall and 2 feet wide. Seeds germinate best when the soil temperatures are over 75. Bottom heat will greatly improve this crops seedling growth and accelerate transplant flower production.
Seeds germinate best when the soil temperatures are over 75.
Some varieties even produce flowers with one color petal and a different color center for a two-toned effect. Jun 25 2021 Common Name. Seeds germinate best when the soil temperatures are over 75. Although temperature is.