The clear crisp flowers and glossy green leaves of the annual vinca are often referred to as Periwinkle. It is not related to the perennial ground cover with the same common name (vinca vine). It is prized for its nonstop flower show from early summer till fall. Annual vinca is drought tolerant and requires almost no maintenance to keep it looking terrific. Use it in beds and borders or tuck it into mixed containers with other annual flowers. Annual vinca grows 12 to 18 inches tall and comes in pink, purple, red, white, magenta, and bi-colors. The flowers are also attractive to butterflies.