Spiranthes australis
austral ladies'-tresses
Eastern and northern Australia, Asia, western Pacific
Overview
Spiranthes australis is a deciduous terrestrial orchid growing from fleshy tuberous roots, sending up a slender flowering spike 6-20 inches (15-50 cm) tall. A few narrow, grass-like leaves form at the base, 2-6 inches (5-15 cm) long, usually withering by flowering time. Many small flowers about 0.2 inch (4-6 mm) long are arranged in a single spiral row up the spike, pink to rose with a white center. Flowering occurs in summer. The spiral arrangement of the flowers gives the plant its common name. After flowering the plant dies back to its tuberous roots and stays dormant until the next season. Growth depends on soil fungi, which makes it hard to transplant or keep in cultivation. Plants are usually short-lived and rely on regular seeding into open, damp ground.
Native Range
Native across eastern and northern Australia and widely through Asia to the western Pacific. Grows in damp grassland, swamp margins, seepage slopes, and moist open woodland, usually in full sun on permanently moist soils.Suggested Uses
Grown by orchid growers in pots of moist, free-draining mix kept damp through the growing season. In natural plantings it occurs in damp grassland and bog gardens. It is not suited to dry borders because of its need for constant moisture and soil fungi.How to Identify
Appearance
Size & Dimensions
Height6" - 1'8"
Width/Spread2" - 4"
Reaches mature size in approximately 4 years
Bloom Information
Flowers in summer, December through March in its native range. The spike opens from the base upward over 2-3 weeks. Flowering is heavier on plants in open, sunny, moist sites.
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 6-10 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
Care & Maintenance
Care Guide
Grows in full sun in permanently moist to wet soils that do not dry out in the growing season. The species depends on specific soil fungi and rarely survives transplanting from the wild. Plants need open, low-competition ground and steady moisture through summer. Drying out during growth ends flowering and can kill the plant. Cultivation is generally limited to growers using symbiotic propagation.Pruning
No pruning is required. The spent flower spike and leaves wither as the plant enters dormancy. Dead growth can be left in place to mark the dormant tuber.Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons