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Pterostylis alpina

Australian mountain greenhood

Orchidaceae South-eastern Australian highlands

Attracts Pollinators

SunPart Shade – Full Shade

WaterMedium

HardinessZones 6–9

Overview

Pterostylis alpina is a terrestrial orchid growing from an underground tuber, producing a single erect stem 4-12 inches (10-30 cm) tall with several stem leaves. Each plant bears one green and translucent-white hooded flower about 0.8-1.2 inches (20-30 mm) long, formed by the fused upper sepal and petals (the galea) curving forward over the column. Two narrow lateral sepals point upward to forward, ending in slender tips. A hinged, sensitive labellum sits within the hood and moves when touched, briefly trapping visiting insects. Non-flowering plants form a flat rosette of leaves at ground level. The species grows in cool, moist montane and subalpine sites and is dormant underground over the dry or cold part of the year. The green flower coloring blends with surrounding foliage, making plants hard to locate when not in bloom.

Native Range

Native to south-eastern Australia, in the highlands of New South Wales, Victoria, the Australian Capital Territory, and Tasmania. Grows in montane and subalpine forest, woodland, and herbfield in moist, humus-rich soils, generally at higher elevations.

Suggested Uses

Occurs as a wild plant of montane and subalpine habitats and is seldom cultivated except in specialist native-orchid collections. It suits cool, shaded terrestrial-orchid pots or protected woodland beds that mimic its alpine conditions. It is not suited to warm or dry garden positions.

How to Identify

Identified by a single green-and-white hooded flower 0.8-1.2 inches (20-30 mm) long on a stem 4-12 inches (10-30 cm) tall, with leaves along the stem rather than only at the base. The two lateral sepals are held erect to forward with slender, tapering tips. Separated from related greenhoods by its alpine to subalpine habitat and the proportions of the galea and sepals; close identification within Pterostylis spp. relies on flower structure.

Appearance

Size & Dimensions

Height4" - 1'

Width/Spread2" - 4"

Colors

Flower Colors

Foliage Colors

Fall Foliage Colors

Bloom Information

Bloom Period

~3 weeks

Spring Summer

Flowers in spring and early summer, mainly October to January depending on elevation and snowmelt, with flowering later at higher sites. Each plant produces a single flower lasting about 2-4 weeks. The above-ground plant then withers, and the tuber remains dormant until the next season.

Detailed Descriptions

Foliage Description

Green

Growing Conditions

Sun Requirements

SunPartial Shade SunFull Shade

Tolerates up to 4 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 - 6.5(Acidic)

357912

Soil Types

loam peat

Drainagemoist

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

3-5 years from seed

Care & Maintenance

Care Guide

Grows in cool, moist, humus-rich soils in part shade and depends on associated soil fungi, which makes it difficult to cultivate or transplant. Moisture through the growing season supports the leaf and flower, while drier dormancy follows in summer or under snow. It grows poorly in warm lowland gardens outside its montane climate. Soil disturbance over the dormant tuber can kill the plant. Slugs and snails graze the soft leaves and flowers in wet conditions. Plants are rarely grown outside specialist terrestrial-orchid collections.

Pruning

No pruning is required. The single flower stem and leaves can be left to die back naturally into dormancy. Removing seed capsules before they ripen reduces self-sown seedlings where the species is cultivated.