Platanthera dilatata
white bog orchid
Overview
Platanthera dilatata is an erect terrestrial orchid in the orchid family, growing 8-40 inches (20-100 cm) tall from fleshy roots. The lance-shaped leaves are 2-8 inches (5-20 cm) long, sheathing the lower stem and reducing in size upward. A dense spike of white flowers tops the stem in summer, each flower about 0.4-0.6 inch (10-15 mm) long with a spurred lower lip widened at its base. The flowers carry a strong sweet, clove-like fragrance, especially in the evening, which draws moths and long-tongued bees. It grows in cold bogs, fens, wet meadows, seeps, and streambanks across the northern and mountainous parts of North America, in consistently wet, often calcium-rich ground. Like other terrestrial orchids, it relies on soil fungi and is slow to establish, making it hard to transplant or cultivate. The plant dies back to its roots in winter and regrows in spring. Bloom lasts a few weeks in midsummer, after which slender seed capsules form. It depends on stable wetland conditions and declines where drainage, grazing, or trampling disturb its habitat.
Native Range
Native to northern and montane North America, from Alaska and across Canada south in the mountains to California, New Mexico, and the northern states, in wet, often calcareous ground.Suggested Uses
Used in specialized bog and wetland gardens and in conservation plantings with intact hydrology. Suited to cold, wet, native habitat rather than ordinary borders. Grown chiefly by orchid and native plant specialists because of its fungal dependence.How to Identify
Appearance
Size & Dimensions
Height8" - 3'4"
Width/Spread4" - 10"
Reaches mature size in approximately 4 years
Bloom Information
Flowers from June to August, in midsummer. The white flowers open from the base of the spike upward over two to four weeks. The clove-like scent is strongest in the evening, when moths visit.
Detailed Descriptions
Foliage Description
greenGrowing Conditions
Sun Requirements
Requires 4-8 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