How to grow lavender cotton
Overview
Lavender cotton is a compact, evergreen shrub with finely textured silver-grey foliage and small yellow button flowers in summer. It is grown primarily for its dense, mounding form that provides structure and contrast in dry, sunny borders, and for its low-maintenance, drought-tolerant nature.
Varieties
- Santolina chamaecyparissus 'Nana' — A dwarf, compact form reaching only 30–40 cm tall, ideal for tight edging and small gardens.
- Santolina chamaecyparissus 'Lemon Fizz' — Produces pale lemon-yellow flowers instead of the typical deep yellow, adding a softer colour note.
Soil Preparation
Prefers a neutral to slightly alkaline pH (6.5–7.5). Ideal soil is sandy or gravelly loam with sharp drainage—do not use clay or heavy garden soil. If your soil is heavy, raise the bed 15–20 cm or plant on a slope. No need to add lime unless pH is below 6.0.
Growing Guide
Plant in full sun in well-drained, sandy or gravelly soil. Space 60–80 cm apart for a dense hedge or edging. Dig a hole twice the width of the pot, backfill with native soil, and water in well. Do not add organic matter or compost to the planting hole—this plant prefers lean conditions. Mulch lightly with gravel or pebbles to keep the crown dry.
Sowing
Sow seeds in spring (temperate) or autumn (subtropical/mediterranean) on the surface of a seed-raising mix, barely covering. Germinates in 14–21 days at 18–22°C. Transplant when 5–8 cm tall. Direct sowing is possible but slower; use pots for best results.
Care
Feed only once in early spring with a very dilute, balanced slow-release fertiliser (e.g. 1/4 strength). Prune back by one-third after flowering to maintain a compact shape and prevent the centre from becoming woody. Remove any dead or leggy stems at the base in late winter.
Companion Planting
Excellent edging plant alongside rosemary, thyme, and lavender. Pairs well with other silver-foliage plants like artemisia and dusty miller. Avoid planting near moisture-loving plants such as ferns or astilbes, as they will create too-wet conditions.
Common Pests & Risks
Root rot (Phytophthora) is the main risk in heavy or waterlogged soils—ensure excellent drainage. Aphids may appear on new growth in spring; blast off with water or apply a dilute neem oil spray. No other significant pests in Australian gardens.
Troubleshooting
Yellowing leaves: usually caused by waterlogged soil—reduce watering and improve drainage. Brown leaf tips: often from salt build-up or over-fertilising—flush soil with water and stop feeding. Leggy, open centre: caused by insufficient pruning—cut back hard by one-third after flowering. Sparse growth in shade: move to full sun—this plant needs at least 6 hours direct light. White powdery coating on leaves: powdery mildew in humid, still air—increase air flow around the plant.