How to grow rosemary grevillea
Overview
Rosemary grevillea is an evergreen shrub with needle-like leaves and spider-like red-pink flowers, native to southeastern Australia. It is grown for its fine texture, drought tolerance, and ability to attract birds. A key requirement is very well-drained soil and low-phosphorus fertiliser.
Varieties
- Rosmarinifolia (species) — The typical form with fine green leaves and reddish-pink flowers.
- 'Rosea' — A selection with deeper pink flowers and a compact habit.
- 'Lutea' — A yellow-flowering form, less common but attractive in mixed landscapes.
Soil Preparation
Prefers slightly acidic to neutral pH (6.0–7.0). Ideal soil is coarse, sandy, and well-drained; add decomposed granite or coarse sand to heavy clay. Avoid phosphorus-rich amendments like blood and bone or superphosphate.
Growing Guide
Position in part shade with protection from hot afternoon sun. Ensure soil is free-draining sandy loam; improve with gravel if clay. Space plants 1–2 m apart. Water moderately after planting, then reduce to occasional deep watering. Avoid any overwatering or wet feet. Use a low-phosphorus native fertiliser in spring.
Sowing
Sow seeds 3–5 mm deep in seed-raising mix, keep moist but not wet, and place in bright filtered light. Germination takes 3–6 weeks at 18–22°C. Transplant when seedlings have 3–5 true leaves. Direct sowing is not recommended; use seed trays or pots.
Care
Feed with a low-phosphorus native fertiliser in early spring. Lightly prune after flowering — trim up to one-third of growth to maintain shape and encourage bushiness. Remove spent flower heads to prolong blooming.
Companion Planting
Works well with other dryland natives such as Westringia fruticosa, Eremophila nivea, and Lomandra longifolia. Avoid pairing with heavy feeders that require high phosphorus, like roses or vegetables.
Common Pests & Risks
Scale insects can appear on stems; control with horticultural oil or white oil spray. Leaf miners may tunnel in leaves; pick off affected leaves or use eco-oil. Avoid strong chemical insecticides that harm beneficial insects.
Troubleshooting
Yellow leaves: often due to phosphorus toxicity or high pH; test soil and stop P fertiliser. Brown leaf tips: underwatering or salt build-up; flush soil and water deeply. Stunted growth: poor drainage or root rot; dig up and improve drainage. Scale insects: check stems for waxy bumps; treat with white oil. Few flowers: too much shade or overfertilising with nitrogen.