This sprawling, mounding, somewhat vine-like, evergreen shrub is quite outstanding because it is covered most of the year with clusters of pale blue, phlox-like flowers (Figure 1). Plumbago is excellent as a foundation planting or when used in planters. It will cascade down a retaining wall, showing off the unusual blue flowers. It has also been sheared into a hedge, but most of the flowers are removed at each pruning.
Scientific name: Plumbago auriculata
Pronunciation: plum-BAY-go ah-rick-yoo-LAY-tuh
Common name(s): plumbago, cape plumbago, sky flower
Plant type: shrub
USDA hardiness zones: 9 through 11 (Figure 2)
Planting month for zone 9: year round
Planting month for zone 10 and 11: year round
Origin: not native to North America
Uses: border; mass planting; container or above-ground planter; hedge; attracts butterflies
Availability: generally available in many areas within its hardiness range
Height: 6 to 10 feet
Spread: 8 to 10 feet
Plant habit: spreading; round
Plant density: moderate
Growth rate: fast
Leaf arrangement: alternate
Leaf type: simple
Leaf margin: undulate
Leaf shape: oblong
Leaf venation: brachidodrome
Leaf type and persistence: evergreen
Leaf blade length: less than 2 inches
Leaf color: green
Fall color: no fall color change
Fall characteristic: not showy
Flower color: blue
Flower characteristic: year-round flowering; pleasant fragrance
Fruit shape: elongated
Fruit length: less than .5 inch
Fruit cover: dry or hard
Fruit color: brown
Fruit characteristic: inconspicuous and not showy
Trunk and Branches
Trunk/bark/branches: not particularly showy; typically multi-trunked or clumping stems
Current year stem/twig color: green
Current year stem/twig thickness: thin
Light requirement: plant grows in part shade/part sun
Soil tolerances: clay; sand; acidic; loam; slightly alkaline
Drought tolerance: moderate
Soil salt tolerances: unknown
Plant spacing: 36 to 60 inches
Roots: sprouts from roots or lower trunk
Winter interest: plant has winter interest due to unusual form, nice persistent fruits, showy winter trunk, or winter flowers
Outstanding plant: not particularly outstanding
Invasive potential: not known to be invasive
Pest resistance: long-term health usually not affected by pests
Use and Management
Needing full sun for best growth and flowering, plumbago will grow on any fertile, well-drained soil, becoming drought-tolerant once established. Leaves may yellow on soils with a high pH, indicating mineral deficiency. Plumbago responds well to an application or two of fertilizer during the growing season to encourage continuous growth and flowering. Excessive growth can be removed at any time of year.
Plants in north-central Florida quickly recover in the spring following a killing freeze. Allow four to six feet between plants in a mass planting so that the natural cascading, fountain shape will develop. Plumbago also looks attractive as a specimen if located in a low ground cover.
The variety 'Alba' has white flowers.
Propagation is by seed, cuttings, or division.
Pests and Diseases
Pest problems include cottony cushion scale and mites.
No diseases are of major concern.