Scientific: Plumbago auriculata
Common: cape plumbago, cape leadwort
Family: Plumbaginaceae
Origin: Southern Africa
Pronounciation: Plum-BA-go a-u-ri-cu-LA-ta
Hardiness zones
Sunset 8, 9, 12-24
USDA 9-11
Landscape Use: Accent, background, raised planters, sprawling cascade effect. Used as in landscapes from maritime coastal southern and central California to the lower deserts of Arizona as a sprawling and informal accent shrub.
Form & Character: Arching and spreading, unruly and informal, delicate, colorful.
Growth Habit: Evergreen, herbaceous to semi-woody, broadleaf perennial shrub, sometimes vigorous and sprawling to 6-feet tall with 10-feet spread. The white flowering cultivar 'Alba' is less vigorous.
Foliage/Texture: Oblong-spatulate, 2-inches long tapering to a short petiole, stipular leaves and semi-angular stems; medium texture.
Flowers & Fruits: Powder blue tubular flowers in terminal clusters; fruit insignificant.
Seasonal Color: Flowers from March to December, heaviest in late summer and early autumn.
Temperature: Tolerant, but high heat fades flower color from a pasty UCLA powder blue to whitish blue.
Light: Full sun to partial shade. In Phoenix, eastern exposures are best, avoid western exposures.
Soil: Iron chlorosis in alkaline soils is common in Phoenix.
Watering: Control growth rate by extending the interval between irrigations. Copious added water encourages vegetative growth at the expense of reproductive growth (aka more water lessens the amenity effect of the flowers).
Pruning: Prune to shape. Do not try and maintain this plant as a clipped hedge, bowling ball, outdoor plant table, or in any other formal shape. Frequent shearing of cape plumbago diminishes bloom potential and will only frustrate those who expect conformity in the natural world.
Propagation: Stem cutting or seed.
Disease and Pests: None
Additional comments: Cape plumbago was once a popular Phoenix landscape shrub in the later half of the 20th century. Nowadays, though still popular in coastal California, its popularity in Phoenix has waned like a pair of 'red ball jets' sneakers. It's important to note the potential size of this sprawling, cascading shrub - it's rather large. It is not suited for use in small areas without extensive pruning maintenance which will reduce floral display if done improperly. Cultivar 'Alba' has white flowers, while 'Royal Cape' and 'Imperial Blue' have sky blue flowers. In Phoenix, the present day emphases on 'desert landscaping' and water conservation means that colorful plants such as cape plumbago are 'out of style'.