How to grow native mint bush
Overview
Prostanthera rotundifolia is a compact, aromatic shrub native to eastern Australia, valued for its rounded, mint-scented foliage and delicate mauve flowers. It serves as a linking plant in garden design, providing consistent texture and seasonal interest in sheltered, part-shaded beds.
Soil Preparation
Prefers slightly acidic to neutral soil (pH 5.5–7.0) with good drainage. Amend heavy clay with coarse sand and decomposed pine bark at a 1:2 ratio. Avoid adding lime or high-phosphorus fertilisers. A 5 cm layer of organic mulch helps retain moisture without waterlogging.
Growing Guide
Plant in well-drained soil enriched with organic matter, in a position that receives morning sun and afternoon shade. Space 60–80 cm apart to allow air circulation and reduce humidity around the foliage. Dig a hole twice the width of the root ball, backfill with native potting mix, and water in well. Mulch lightly with fine bark to retain moisture without smothering the crown. Avoid planting in heavy clay or low spots where water pools.
Care
Feed with a low-phosphorus native fertiliser (e.g., 2–3% P) in early spring and again in autumn. Prune lightly after flowering to maintain a rounded shape and encourage dense, bushy growth. Remove any dead or crossing branches to improve air flow. Do not overwater; allow the top 5 cm of soil to dry between waterings.
Companion Planting
Pair with other aromatic natives like Correa alba, Westringia fruticosa, and Hardenbergia violacea for a cohesive, low-maintenance bed. Avoid placing near heavy feeders such as citrus or vegetables that demand high nitrogen, as the mint bush prefers low-phosphorus conditions.
Common Pests & Risks
Scale insects (especially Eriococcus species) can appear on stems and leaves; treat with horticultural oil in early spring. Root rot (Phytophthora) is common in poorly drained or overwatered sites; improve drainage and avoid heavy mulching. Monitor for sooty mould on foliage if scale is present.
Harvesting
Harvest use is limited
Troubleshooting
Yellow leaves: often caused by overwatering or poor drainage; reduce watering and check soil moisture. Brown leaf edges: usually from hot afternoon sun or dry wind; move to a more sheltered position. Stunted growth: may indicate low phosphorus or root-bound pot; repot or feed with native fertiliser. Leaf drop: common after transplant shock; keep consistently moist for 2–3 weeks. Sooty mould: treat underlying scale infestation with horticultural oil.