Platanthera unalascensis, commonly known as slender-spire orchid, Alaska piperia, or Alaska rein orchid, is a perennial herb native to a variety of habitats including moist meadows, forest clearings, grassy slopes, and along streams in western North America, from Alaska through the southwestern United States, and extending to eastern Canada and the Great Lakes region. It typically grows to about 28 inches tall, with a basal rosette of leaves up to 6 inches long. The plant features a slender, spikelike inflorescence of widely spaced, translucent green flowers that emit a musky, soapy, or honeylike fragrance in the evenings. The flowers bloom from late spring to midsummer and are particularly showy due to their unique structure and evening fragrance.

The slender-spire orchid is valued for its ornamental fragrance and is used in naturalized plantings, woodland gardens, and as a specimen in native plant collections. It thrives in part shade to full sun, prefers moist to wet soil conditions, and requires good drainage. While it is not commonly found in the horticultural trade, it is appreciated by native plant enthusiasts and is sometimes used in restoration projects. Care should be taken not to overwater, as it does not tolerate waterlogged conditions.CC BY-SA 4.0