How to grow spear grass
Overview
Spear grass (Austrostipa stipoides) is a clumping, fine-leaved perennial grass native to coastal dunes and dry sites of southern Australia. It is grown for its soft, arching foliage that adds movement and texture to garden beds, and for its exceptional drought tolerance once established.
Soil Preparation
Prefers sandy or gravelly, well-drained soil with pH 6.0–7.5. Amend heavy clay with coarse sand or gravel to improve drainage. Do not add rich compost — this grass thrives in lean, free-draining conditions.
Growing Guide
Plant in full sun in well-drained sandy or loamy soil; avoid heavy clay. Space clumps 40–60 cm apart. Water deeply but infrequently after planting to encourage deep roots. Do not overwater — this grass is adapted to dry coastal conditions. Sow seed directly in autumn or spring, or plant potted divisions. Mulch with gravel or coarse sand to suppress weeds and mimic its native habitat.
Sowing
Sow seed 3–5 mm deep in seed-raising mix, keep moist until germination (14–21 days). Direct sow in autumn or spring. Transplant seedlings when 10 cm tall. Not commonly grown from seed in home gardens — divisions are easier.
Care
Feed lightly in spring with a slow-release native fertiliser (low phosphorus). Cut back old foliage to ground level in late winter or early spring to encourage fresh growth. No regular pruning needed beyond this annual tidy.
Companion Planting
Excellent with pigface (Carpobrotus glaucescens) and banksia (Banksia integrifolia) for a coastal or habitat garden. Avoid planting near moisture-loving ferns or lush perennials that would compete poorly with its dry-adapted roots.
Common Pests & Risks
Generally pest-free. Occasionally scale insects or aphids may appear on old foliage; treat with a blast of water or horticultural oil. Fungal issues only if overwatered — ensure free drainage and avoid wetting foliage at night.
Troubleshooting
Yellowing foliage: usually old leaves — cut back in late winter. Brown leaf tips: sign of underwatering or salt stress; flush soil with fresh water. Sparse growth: too much shade or overwatering. Root rot: only in poorly drained soil — move to a raised bed or gravel mound.