A sprawling, long-blooming evergreen shrub also known as cape plumbago, blue plumbago (Plumbago auriculata) produces clusters of flowers ranging from pale blue to bright sky blue throughout spring and summer. In climates with frost-free winters, the plant blooms nearly year round. Blue plumbago reaches a height of 3 to 4 feet at maturity, with a spread of about 5 feet. A heat-loving plant that performs best in bright sunlight, blue plumbago is suitable for planting in U.S. Department of Agriculture plant hardiness zones 8 through 11. (Ref. 1)
Water blue plumbago whenever the top of the soil feels dry to the touch -- usually once every week during dry weather. Provide 1 to 1 1/2 inch of water each time. Water with a soaker hose or let a garden hose run slowly at the base of the plant. Let the top of the soil dry between waterings because blue plumbago is a relatively drought-tolerant plant.
Spread 1 to 2 inches of bark chips or other mulch around the plant to conserve soil moisture and keep weeds in check.
Feed blue plumbago in early spring, using a slow-release, dry, 12-12-12 fertilizer. Apply the fertilizer at a rate of approximately 1 1/2 tablespoons per plant.
Cut blue plumbago back to about 3 inches in late winter or early spring. You can also cut the plant back in late autumn, but leaving the foliage in place adds interest to the winter landscape and helps protect the plant from winter cold.
Trim the plant to maintain the desired size and shape in midsummer or whenever it begins to look tired or straggly. Make each cut about 1/4 to 1/2 inch above a leaf or bud to prevent unsightly stubs.
Remove blooms as soon as they wilt. This process, known as deadheading, keeps the plant neat and stimulates continued blooming throughout the season. Remove the wilted bloom along with the stem down to the next leaf or branch.