Plant Library mat rush
Grass · Part Shade

How to grow mat rush

Lomandra hystrix
mat rush
Photo: MargaretRDonald / Wikimedia Commons (CC BY-SA 4.0)
☀️
Part Shade
Sun
💧
Medium
Water
📐
70–120 cm
Spacing
❄️
Low
Frost tolerance

Overview

Mat rush (Lomandra hystrix) is a clumping, strappy perennial grass from the Asparagaceae family, valued for its graceful, arching foliage and ability to add movement and texture to garden beds. It is a key plant for erosion control on moist, shaded slopes and thrives in part-shade with consistent moisture.

Varieties

  • Lomandra hystrix 'Tropic Cascade' — Compact, weeping form ideal for small gardens and pots.
  • Lomandra hystrix 'Katie Belles' — Dwarf variety with fine, blue-green foliage, excellent for groundcover.

Soil Preparation

Prefers slightly acidic to neutral soil (pH 6.0–7.0). Enrich with compost or aged manure before planting; improve drainage on heavy clay by adding gypsum or coarse sand. Mulch with bark to retain moisture.

Growing Guide

Plant mat rush in part-shade to full shade, avoiding hot afternoon sun in warmer zones. Space clumps 60–80 cm apart for a dense groundcover. Prepare soil with well-rotted organic matter and ensure good drainage; it tolerates clay but not waterlogging. Water regularly during establishment, then reduce to weekly in temperate zones. For erosion control, plant on contours or use a staggered grid.

Sowing

Sow seed 5 mm deep in seed-raising mix, keep moist and warm (20–25°C). Germination takes 3–6 weeks. Direct sow in spring or early summer; transplant seedlings at 2–3 true leaves. Best results from division of established clumps.

Care

Feed with a slow-release native fertiliser in early spring. Prune back old, tattered leaves to 10 cm in late winter to encourage fresh growth. No heavy maintenance needed; just remove spent flower stems after they dry.

Companion Planting

Pair mat rush with other moisture-lovers like ferns (e.g., Blechnum), liriope, and native violets (Viola banksii). Avoid planting near aggressive grasses like kikuyu or buffalo, which can smother it. It also works well under deciduous trees like crepe myrtle.

Common Pests & Risks

Mat rush is largely pest-free but may attract scale insects or mealybugs in humid conditions. Treat with a horticultural oil spray or introduce beneficial insects. Slugs and snails can damage new shoots; control with iron-based baits.

Troubleshooting

Yellow leaves: overwatering or poor drainage; reduce watering and check soil. Brown leaf tips: dry air or salt burn; increase humidity or flush soil. Stunted growth: heavy shade or compacted soil; move to brighter spot or aerate. Leaf spots: fungal infection in wet weather; improve air circulation and remove affected leaves.

Planting Calendar

Climate zone
Plant / repot
Transplant
Peak season
Temperate Melbourne · Adelaide · coastal NSW · most of NZ
Sep–Nov
Oct–Dec
Mediterranean Perth · Eyre Peninsula
Mar–May
Apr–Jun
Subtropical Brisbane · coastal QLD · northern NSW · Auckland
Aug–Oct
Sep–Nov

Common Questions

How long does mat rush take to grow?
Mat rush reaches full size in 2–3 years; clumps spread 60–80 cm wide. It is slow to establish but long-lived.
Can mat rush grow in a pot?
Yes, in a large pot (30+ cm) with good drainage. Use a native potting mix and water regularly; it will need dividing every 3–4 years.
When should I plant mat rush in Australia?
In temperate and subtropical zones, plant in spring (Sep–Nov). In Mediterranean zones, plant in autumn (Mar–May) to avoid summer heat.
How much water does mat rush need?
Water weekly during establishment, then every 2–3 weeks in temperate zones. In subtropical areas, it may need more frequent watering in dry spells.
What are good companion plants for mat rush?
Ferns, liriope, and native violets are ideal. Avoid aggressive grasses like kikuyu.
How do I prune mat rush?
Cut back old leaves to 10 cm in late winter. Remove spent flower stems after they dry.
Does mat rush have any common pests?
Scale and mealybugs can occur; treat with oil spray. Slugs may attack new shoots.
Can mat rush handle frost?
It tolerates light frost (to -5°C) but may suffer in hard frosts. Protect with mulch or move to a sheltered spot.

Quick Facts

Sun Part Shade
Water Medium
Spacing 70–120 cm
Frost tolerance Low

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