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Microtis unifolia

common onion-orchid

Orchidaceae

Australia, New Zealand, and eastern Asia

Attracts Pollinators Container Friendly

SunFull Sun – Part Shade

WaterMedium

HardinessZones 8–10

Overview

Microtis unifolia is a small terrestrial orchid in the family Orchidaceae, growing each season from an underground tuber to a flowering height of 6-24 inches (15-60 cm). A single hollow, cylindrical leaf wraps the lower stem like an onion leaf, 6-16 inches (15-40 cm) long, and gives the orchid its common name. The slender flowering spike carries many small green flowers about 0.1-0.2 inch (3-5 mm) across, densely arranged toward the top, each with a broad lower lip and a hooded upper segment. Flowering is in spring and early summer, and the plant dies back to the tuber after seed set, reappearing the following season. New tubers form each year, so colonies build up over time. Growth depends on seasonal moisture, and plants may skip flowering in dry years. The small green flowers blend with the surrounding foliage.

Native Range

Native to Australia, New Zealand, and parts of eastern Asia, growing across all Australian states. It occurs in grassland, open woodland, heath, and disturbed sites, including lawns and roadsides, on a wide range of soils.

Suggested Uses

Grown mainly in native grassland restoration, orchid collections, and informal lawns where it appears on its own, rather than as a planted ornamental. It suits naturalistic and conservation plantings on undisturbed ground. Specialist growers raise it in pots with the appropriate soil fungus.

How to Identify

Recognized by a single hollow, onion-like leaf 6-16 inches (15-40 cm) long wrapping the lower stem, and a slender spike of many small green flowers 0.1-0.2 inch (3-5 mm) across. Each flower has a broad lower lip and a hooded upper segment. The solitary tubular leaf and crowded green flowers separate it from grasses and from other terrestrial orchids with larger coloured flowers.

Appearance

Size & Dimensions

Height6" - 2'

Width/Spread2" - 4"

Reaches mature size in approximately 2 years

Colors

Flower Colors

green

Foliage Colors

green

Bloom Information

Bloom Period

~3 weeks

Spring Summer

Flowers in spring and early summer (September to January), with timing depending on rainfall and region. The many small flowers open over two to three weeks along the spike. Plants may not flower at all in dry seasons.

Detailed Descriptions

Foliage Description

green

Growing Conditions

Sun Requirements

SunFull Sun SunPartial Shade

Requires 4-9 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 clay

Drainagewell drained

Water & Climate

Water Needs

Medium

Frost Tolerance

hardy

Time to Maturity

2-3 years

Care & Maintenance

Care Guide

Grows in full sun to part shade on most soils with seasonal moisture, from sandy to clay loams. As a tuberous orchid it relies on a symbiotic soil fungus and on undisturbed ground, so it is difficult to transplant or cultivate deliberately. Moisture through autumn and winter supports leaf and flower growth, after which the plant dies back over summer. It needs no feeding and appears on its own in lawns and garden beds with suitable conditions. Soil disturbance, heavy fertilizing, and loss of the fungal partner are the main reasons colonies decline.

Pruning

No pruning is required for this small tuberous orchid. Spent flower spikes can be removed after seed set if self-seeding is not wanted. The foliage dies back naturally to the tuber and is left in place to feed the next season growth.