Spiranthes spp.
Ladies'-tresses
Mainly the Americas, with species in Eurasia and Australasia
Overview
Spiranthes spp. is a genus of about 35–50 terrestrial orchids in the family Orchidaceae, the ladies'-tresses, found mainly in the Americas with additional species across Eurasia and into Australia. Plants grow from clusters of thickened, tuberous roots and send up a basal rosette or tuft of narrow, grass-like to lance-shaped leaves, from which a slender flower spike rises 4–20 in (10–50 cm) tall. The small flowers, usually white to cream and occasionally pinkish, are arranged in one or more spiralling ranks up the spike, the twist giving the plants their braided, plait-like look and their common name. Each tubular flower is about 0.2–0.5 in (5–12 mm) long, with a frilled or downcurved lip, and many species are fragrant. Flowering ranges from late spring to autumn depending on species. Spiranthes spp. grows in damp meadows, fens, prairies, streambanks, lawns, and roadside verges, usually in full sun to light shade on moist soil. The plants depend on soil fungi, can be slow to establish, and some species are uncommon or legally protected in parts of their range.
Native Range
Spiranthes spp. is most diverse in North America, with species ranging across the continent and south into Central and South America, plus a scatter of species in Europe, Asia, and Australasia. The orchids grow in moist, open habitats including wet meadows, fens, seepage slopes, prairies, and grassy roadsides, often on neutral to slightly acidic soils.Suggested Uses
Spiranthes spp. is grown in bog gardens, damp borders, and wildflower or prairie plantings where soil stays moist, and the fragrant autumn-flowering species extend interest late in the year. Container culture in a moisture-retentive mix suits the smaller species. The plants are mainly grown by hardy-orchid and native-plant enthusiasts rather than in general borders.How to Identify
Appearance
Size & Dimensions
Height4" - 1'8"
Width/Spread4" - 10"
Reaches mature size in approximately 3 years
Bloom Information
Flowering ranges from late spring to autumn, with most North American species blooming from midsummer into fall, roughly July to October. The flowers open from the base of the spiral upward over two to four weeks. Several species release a sweet fragrance, strongest in the morning, and are pollinated chiefly by bumblebees.
Detailed Descriptions
Flower Description
white to cream, sometimes pink-tingedFoliage Description
greenGrowing Conditions
Sun Requirements
Requires 4-10 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
Spiranthes spp. grows in full sun to light shade on consistently moist, humus-rich soil, conditions matching the wet meadows and fens where the orchids occur. Neutral to slightly acidic ground suits most species, and the plants are intolerant of drying out during growth. Like other terrestrial orchids they rely on soil fungi and can be slow to settle and flower after transplanting. A surface mulch of leaf mould or sand conserves moisture and protects the shallow tuberous roots. Propagation is by division of the root clusters when dormant or by seed sown with the appropriate fungus. Several species adapt to a sunny, moist border or bog garden, while others are difficult outside their native habitat.Pruning
Pruning is limited to removing the spent flower spike after seed is shed, unless seed is wanted. The narrow leaves are left to feed the roots and are cleared only once they have died back. The dormant root clusters are left undisturbed.Pruning Schedule
J
F
M
A
M
J
J
A
S
O
N
D
fall
Container Growing
✓ Suitable for container growing
Minimum container size: 1 gallons