Vinca is a flowering annual plant that grows as a perennial in the South. Vinca comes in three varieties. Creeping vinca has long, cascading stems and grows best in hanging pots. Dwarf vinca is a small, dense plant that never grows taller than 12 inches. Border vinca is a larger version of the dwarf vinca, and grows flowers that are 2 inches in diameter. All vincas are drought tolerant and have the same specific watering needs.
Plant vinca in well-drained soil. If you plant in a container, the container must have drainage holes on the bottom of the flower pot.
Water vinca flowers during the predawn or early morning hours. Watering early in the morning allows the excess water to drain away or evaporate during the daylight hours. If vinca is watered too late in the day, the excess water remains on the plant all night. Vinca is susceptible to fungal infections, which are caused by excess moisture.
Pour water directly onto the soil when watering vinca. Avoid watering from overhead, so that the foliage and flowers do not get wet. If you like to water by hand, use a watering can that has a narrow spout that fits underneath the plant's foliage. If you prefer to water with a hose, use a drip irrigation system placed underneath the foliage.
Water every other week, or if the top 2 inches of soil feel dry to the touch. Vinca is very drought tolerant and prefers its soil to be on the dry side of moist. Do not wait too long to water, though. If a vinca starts to wilt, it will likely die; is very difficult to nurse a wilted vinca back to life with water.