Round Leaf Mint Bush

Round Leaf Mint Bush (Prostanthera rotundifolia) earns its keep twice over. Brush past it and the small round leaves release a sharp mint scent, then in spring the whole shrub disappears under a haze of purple flowers. It reaches about 2.5m tall and 2m wide, fast enough to soften a fence line within a few seasons, and handles frost, drought and poor soil once established. The one thing it will not forgive is wet feet.

Why you'll love it

• Aromatic foliage you actually notice. The rounded leaves carry a strong mint fragrance, released when someone walks past or the wind moves through it.
• A spring flowering worth planning around. Purple blooms cover the branches so heavily the foliage almost vanishes for several weeks.
• Frost hardy and drought tolerant. Once established it copes with cold southern winters and dry summers, in ground too poor for most flowering shrubs.
• Nectar for birds and insects. Honeyeaters, native bees and butterflies all work the spring flowers.

Where it works best

Informal screening and hedging. Plant 1.2m apart for a screen that closes over without being clipped square. At 2.5m it covers a standard fence and beyond.

Mass planting on slopes and banks. Its tolerance of poor, gravelly soil suits difficult ground at the edge of a block, where drainage is naturally sharp.

Feature planting near paths. Site one beside a path, a gate or a seat, so the scent gets used rather than wasted at the back of a bed.

Growing round leaf mint bush in Australia

Position and climate. Full sun gives the heaviest flowering, though it takes light shade in hot inland gardens. This is a plant for warm temperate, cool temperate and Mediterranean climates. Humid tropical and subtropical gardens are the wrong fit, because constant warmth and moisture bring root problems.

Soil. Drainage matters more than fertility. It grows happily in sandy, gravelly and poor soil, but heavy clay that stays wet will kill it. On clay, plant on a mound at least 200mm high.

Water and feed. Water deeply once or twice a week through the first summer, then leave it to the weather. Use a low phosphorus native fertiliser in early spring, lightly: overfeeding produces soft growth and a shorter life.

Pruning. Prune straight after flowering, taking up to a third off the new growth to keep it dense. Do not cut into bare old wood, because it reshoots poorly. Five to eight years is a good run for this species, and an annual light prune is the best way to stretch it.

What to expect when it arrives

We grow it in three sizes. Tube stock is young and single stemmed, the sensible choice for a long run of screening because it catches larger plants within two seasons. The 140mm size comes in packs of ten, ready to plant along a boundary. The 250mm size is sold in packs of three and is on backorder, so allow extra time.

Plants travel upright and are delivered Australia wide, with delivery from $29.95. Advanced and large stock is freighted at cost. Expect a quiet first month, then quick growth through the first warm season. Every plant carries our 30 day healthy plant guarantee.

Plant care guides and related reading

• Plan an Australian native garden
• Browse Australian native shrubs
• Compare hedging and screening plants
• Screening plants from 2m to 4m

Common questions

Does the foliage really smell like mint?

Yes. The scent sits in the leaf and releases when the foliage is crushed or brushed, rather than carrying on the air. It is closer to sharp bush mint than garden mint.

How long will it live?

Five to eight years is typical, and in poorly drained ground much less. Sharp drainage and an annual prune after flowering make the biggest difference, and many gardeners plant a replacement once one starts thinning.

Will it survive frost?

It is frost hardy and suited to cool temperate gardens, so ordinary winter frosts are no problem once established. Young plants in their first winter still benefit from shelter.