Calochilus robertsonii (Purple Beard Orchid)

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Calochilus spp.

beard orchid

Orchidaceae

Australia, New Zealand, New Caledonia, SE Asia

Attracts Pollinators

SunFull Sun – Part Shade

WaterLow

HardinessZones 9–10

Overview

Calochilus spp. is a genus of terrestrial orchids in the family Orchidaceae, native to Australia, New Zealand, New Caledonia, and parts of Southeast Asia, known as beard orchids. Each plant grows from a pair of underground tubers and sends up a single fleshy stem 8-24 inches (20-60 cm) tall, often with one channelled, grass-like leaf at the base. The stem carries a few to many flowers, green to reddish-bronze, whose broad labellum is densely covered in long, gland-tipped hairs that form the beard giving the genus its name. The hairs and metallic colours mimic a female wasp, and male wasps attempting to mate transfer pollen between flowers. Plants are dormant as tubers over the dry season and depend on soil fungi, so they are very hard to grow away from their habitat. Calochilus spp. occupies well-drained, often seasonally moist soils in heath, woodland, and grassland, and many species flower more freely after summer fire.

Native Range

Calochilus spp. is native to Australia, where it is most diverse, and extends to New Zealand, New Caledonia, and parts of Southeast Asia. Plants grow in well-drained sandy or loamy soils of open heath, eucalypt woodland, and grassland, often in ground that is moist in winter and dry in summer.

Suggested Uses

Calochilus spp. is grown almost only in native-orchid and conservation collections rather than general gardens. It features in displays of Australian terrestrial orchids and in habitat protection within its native range. Its fungal dependence rules out routine garden and container use.

How to Identify

Look for a single upright fleshy stem with green to bronze flowers, each with a broad lower lip clothed in long, reddish, gland-tipped hairs that form a conspicuous beard. A single channelled basal leaf is usually present early in the season. The bearded labellum separates Calochilus spp. from other Australian terrestrial orchids.

Appearance

Size & Dimensions

Height8" - 2'

Width/Spread2" - 4"

Colors

Flower Colors

green

red

bronze

Foliage Colors

green

Bloom Information

Bloom Period

~4 weeks

Spring Summer

Flowering occurs mainly in spring and early summer, around September to January in the southern hemisphere, varying with species and rainfall. Each stem opens its flowers in sequence over two to four weeks. Many species flower more freely in the season after a summer bushfire.

Detailed Descriptions

Flower Description

Green to reddish-bronze with a reddish beard

Foliage Description

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 Range5.0 - 7.0(Neutral)

357912

Soil Types

sand loam

Drainagewell drained

Water & Climate

Water Needs

Low

Frost Tolerance

hardy

Time to Maturity

Several years from seed to flowering

Care & Maintenance

Care Guide

These orchids are rarely cultivated and depend on a symbiotic soil fungus for germination and growth, so moved tubers usually fail. In habitat they need an open, sunny to lightly shaded position in well-drained sandy or loamy soil that is moist through winter and spring and dry over summer dormancy. The paired tubers sit a few inches below the surface and reshoot with autumn and winter rains. Clearing, grazing, and altered fire regimes reduce wild populations. Specialist growers keep them in terrestrial-orchid mixes with their fungal partner and water only during active growth.

Pruning

No pruning is required. The leaf and flowering stem wither as the plant returns to summer dormancy, and the dead growth can be left over the resting tubers. Spent flower stems can be removed once seed is shed if self-sowing is not wanted.