Calochilus robertsonii
purple beard orchid
Southeastern Australia and New Zealand
Overview
Calochilus robertsonii is a terrestrial orchid of southeastern Australia and New Zealand that grows from an underground tuber. Each plant produces a single channeled basal leaf, triangular in cross-section, 4-12 inches (10-30 cm) long, which emerges in the cooler months and withers as flowering ends. A single erect flowering stem rises 8-20 inches (20-50 cm) and carries up to nine flowers. Each flower spans about 0.8-1.2 inches (2-3 cm), with greenish to reddish-brown sepals and petals framing a labellum densely covered in long metallic purple to bronze hairs, the feature that gives the beard orchids their name. Flowering occurs in spring, after which the plant dies back to its tuber and rests through the dry summer. Like most Australian terrestrial orchids, it depends on symbiotic soil fungi to germinate and establish, which makes it slow and unreliable to grow outside its natural habitat. It occurs in open eucalypt forest, woodland, and heath on free-draining sandy or loamy soils. Plants are often solitary and stay inconspicuous among grasses until the flower spike appears. Populations rise and fall from year to year with rainfall, and individual tubers may stay dormant below ground through dry seasons without producing a leaf.
Native Range
Native to southeastern Australia, including Victoria, New South Wales, Tasmania, South Australia, and southern Queensland, and also occurring in New Zealand. It grows in open eucalypt forest, woodland, and coastal heath on well-drained soils.Suggested Uses
Calochilus robertsonii is grown almost exclusively by native orchid enthusiasts and in conservation collections rather than in general gardens. In its native range it forms part of the ground flora of eucalypt woodland and features in bushland study and restoration.How to Identify
Appearance
Size & Dimensions
Height8" - 1'8"
Width/Spread4" - 8"
Bloom Information
Flowers appear in spring, mainly September to November, with timing shifting by latitude and seasonal rainfall. Each spike opens its flowers in succession over about two to four weeks. The flowers are short-lived and may be partly self-pollinating as well as drawing male wasps by scent.
Detailed Descriptions
Flower Description
Greenish to reddish-brown with metallic purple to bronze labellum hairsFoliage Description
GreenGrowing Conditions
Sun Requirements
Requires 3-6 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