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Prostanthera lasianthos

christmas bush

Lamiaceae South-eastern Australia

Attracts Pollinators Attracts Butterflies Fragrant (moderate)Container Friendly

SunFull Sun – Part Shade

WaterMedium

HardinessZones 9–10

Overview

Prostanthera lasianthos is an evergreen shrub to small tree growing 1-6 m (3-20 ft) tall and 1.5-4 m (5-13 ft) wide, occasionally taller in sheltered forest. It has an upright, multi-stemmed form with arching upper branches. The lanceolate leaves are 3-12 cm (1.2-4.7 in) long, dark green, with toothed margins, and release a mint-like scent when crushed. From late spring into summer the plant carries large terminal panicles of two-lipped flowers, each 1-1.5 cm (0.4-0.6 in) long, white to pale mauve with purple and orange spotting in the throat. Flowering peaks around December, the source of the common name Christmas bush. It grows naturally along streams, in moist gullies, and in cool forest, and is fast-growing but relatively short-lived, often declining after ten to fifteen years. The shrub needs steady moisture and shelter from hot dry wind, which can scorch the foliage. Hard frost damages soft new growth, though established plants recover.

Native Range

Native to south-eastern Australia, occurring in Victoria, New South Wales, Tasmania, southern Queensland, and south-eastern South Australia. It grows along streams, in moist gullies, and in cool eucalypt forest.

Suggested Uses

Grown as a fast screening or feature shrub in moist native and woodland gardens. Used along watercourses and in sheltered courtyards and large containers. Suited to cottage and bird-attracting plantings in cool, moist districts.

How to Identify

Identified by lanceolate, toothed, dark green leaves 3-12 cm (1.2-4.7 in) long that smell of mint when crushed. The two-lipped white to mauve flowers, spotted purple and orange in the throat, are carried in large terminal panicles. The tall shrubby habit and large flower clusters separate it from smaller-flowered Prostanthera spp. species.

Appearance

Size & Dimensions

Height3'3" - 19'8"

Width/Spread4'11" - 13'1"

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~8 weeks

Spring Summer

White to pale mauve flowers open from November to February, peaking around December. The flowers are massed in branched terminal panicles and draw bees and other insects. Bloom lasts several weeks before the small fruits form.

Detailed Descriptions

Flower Description

white to pale mauve

Foliage Description

dark green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-8 hours of direct sunlight daily

• Full Sun: 6+ hours of direct sunlight

• Partial Shade: 3-6 hours of direct sunlight

• Full Shade: Less than 3 hours of direct sunlight

Soil Requirements

pH Range5.5 - 7.0(Neutral)

357912

Soil Types

loam sand

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

3-5 years

Care & Maintenance

Care Guide

Grows in part sun to dappled shade in moist, free-draining soil enriched with organic matter. Steady moisture suits it through the warm months, and roots benefit from a cool mulch. Shelter from hot dry wind and afternoon sun reduces leaf scorch. It responds to light feeding in spring with vigorous growth. Hard frost can damage soft new shoots, though established plants resprout. The shrub is fast-growing and relatively short-lived, so replacement every ten to fifteen years is common.

Pruning

Trimming lightly after flowering keeps a dense, bushy shape and limits the open, leggy growth that develops with age. Cutting back into older bare wood is risky, as the shrub regenerates slowly from hard pruning. Removing spent flower panicles tidies the plant.