How to grow plumbago
Overview
Plumbago auriculata is a sprawling evergreen shrub from South Africa, grown for its profusion of pale blue flowers and dense foliage. It is commonly used as an informal hedge, groundcover, or background plant in warm gardens. Key: full sun and well-drained soil are essential for heavy blooming.
Varieties
- Plumbago auriculata 'Alba' — White-flowered form, ideal for contrast in warm gardens.
- Plumbago auriculata 'Royal Cape' — Deep blue flowers, more compact than the species.
- Plumbago auriculata 'Monott' (Mono Blue) — A compact, free-flowering variety suited to pots and small gardens.
Soil Preparation
Plumbago prefers a slightly acidic to neutral pH (6.0–7.0) and well-drained soil. Improve heavy clay with gypsum and organic matter; for sandy soils, add compost to retain moisture. Good drainage is critical to prevent root rot.
Growing Guide
Plant plumbago in full sun for best flowering and compact growth. Space plants 1–1.5 m apart for a hedge or 2 m for individual shrubs. It tolerates poor soils but prefers free-draining conditions; avoid heavy clay or waterlogged sites. Water deeply until established, then reduce to occasional deep soaks. Prune after flowering to maintain shape and encourage repeat blooms.
Care
Feed with a balanced slow-release fertiliser in early spring and again in midsummer. Prune hard after the main flowering flush to control size and promote bushiness; remove any frost-damaged wood in late winter. Deadhead spent flowers to extend blooming.
Companion Planting
Good companions include heat-loving plants such as lantana, bougainvillea, and salvia. Avoid planting plumbago near frost-sensitive species that need protection, as its spread may smother smaller plants. It also works as a filler between taller shrubs like grevillea or abelia.
Common Pests & Risks
Scale insects and whitefly are the most common pests on plumbago in Australian gardens. Treat with horticultural oil or insecticidal soap; encourage beneficial insects like ladybirds. Root rot can occur in poorly drained soils, so ensure good drainage.
Troubleshooting
Yellowing leaves: often due to overwatering or poor drainage; reduce water and improve drainage. Leaf drop: caused by cold temperatures; protect from frost or move indoors in cool areas. Sparse flowering: lack of sun; ensure full sun exposure. White fluffy masses on stems: mealybugs; treat with neem oil. Stunted growth: rootbound pot or nutrient deficiency; repot or fertilise.