Hypocalymma angustifolium (White Myrtle)

Hypocalymma spp.

Attracts Pollinators Attracts Butterflies Drought Tolerant Fragrant (light)Container Friendly

SunFull Sun – Part Shade

HardinessZones 9–11

Overview

Hypocalymma spp. is a genus of about thirty shrubs in the myrtle family, Myrtaceae, almost all native to the south-west of Western Australia, with a few species in the east. Most are compact, twiggy shrubs 1.5-5 feet (0.5-1.5 m) tall, with slender stems and small, narrow, aromatic leaves set in opposite pairs. Through winter and spring the stems line up with many small five-petalled flowers in white, pink, or rose, each with a central tuft of stamens, so flowering branches can be wreathed in colour along their length. H. robustum, the Swan River myrtle, carries deep pink flowers on arching stems, while H. angustifolium bears white to pale pink blooms. The flowers are followed by tiny woody capsules. Hypocalymma spp. grows in heath, scrub, and open woodland on sandy, free-draining soils, often where winters are wet and summers dry. The genus needs sharp drainage and is prone to root rot in heavy or wet ground, and most species are tender to hard frost. Several are grown for the dense stem-length flowering and the aromatic foliage.

Native Range

Native to Australia, chiefly the south-west of Western Australia, in heath, scrub, and open woodland on sandy soils.

Suggested Uses

Grown in native, low-water, and coastal gardens in Australia and similar climates, in shrub borders and on sandy banks. The stem-length flowering suits informal and cottage-style plantings, and stems are used as cut flowers. Compact species are grown in containers and rockeries.

How to Identify

Recognised as compact, twiggy shrubs with small, narrow, aromatic leaves in opposite pairs and stems lined with many small five-petalled flowers in white, pink, or rose, each with a tuft of stamens. Crushed leaves are scented. The flowers crowd the stem length rather than forming separate heads, and tiny woody capsules follow.

Appearance

Size & Dimensions

Height1'6" - 5'

Width/Spread1'6" - 5'

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~6 weeks

Winter Spring

Most Hypocalymma spp. species flower through winter and spring, roughly July to November in Australia. Many small flowers open along the length of the stems over several weeks. Tiny woody capsules form after flowering.

Detailed Descriptions

Flower Description

White, pink, rose

Foliage Description

Green to grey-green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 5-9 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 Range5.0 - 7.0(Neutral)

357912

Soil Types

sand loam rocky

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

tender

Time to Maturity

2-3 years

Drought Tolerance

Drought tolerant when established

Care & Maintenance

Care Guide

Most Hypocalymma spp. species grow in full sun to light shade on sandy, gravelly, free-draining soils low in phosphorus. Sharp drainage is essential, as the genus rots in heavy or waterlogged ground. Plants tolerate dry summers once established and suit Mediterranean and warm-temperate climates with wet winters. Low-phosphorus native fertiliser is used, since high phosphorus harms many Australian myrtles. Watering is moderate while young and sparing once established. Most species are frost-tender and are grown in mild areas or given winter protection.

Pruning

A light trim after flowering keeps the shrub compact and encourages new flowering wood. Only the current season growth is cut, as hard pruning into bare wood is poorly tolerated. Spent flowering stems are shortened to a leafy node.