Summer heat can’t keep vinca from performing. The main problem is preventing diseases such as aerial phytophora. This can mainly be done by mulching plants with course material before watering to prevent soil from splashing on the foliage, which is the carrier of the disease. Once the disease has infected a plant it can not be saved.

Transplant into the landscape when soil temperatures are above 70-80 degrees. Cold temperatures will stall the plants and stunt growth. Once established the plants are very drought tolerant and love the summer heat.