Introduction

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.

General Information

Scientific name: Plumbago auriculata

Pronunciation: plum-BAY-go ah-rick-yoo-LAY-tuh

Common name(s): plumbago, cape plumbago, sky flower

Family: Plumbaginaceae

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

Description

Height: 6 to 10 feet

Spread: 8 to 10 feet

Plant habit: spreading; round

Plant density: moderate

Growth rate: fast

Texture: fine

Foliage

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

Flower color: blue

Flower characteristic: year-round flowering; pleasant fragrance

Fruit

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

Culture

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

Other

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.