Bletilla

Bletilla, commonly recognized as the urn orchid, is a genus of terrestrial orchids thriving in temperate climates. The genus is native to a wide geographic range encompassing East Asia and Southeast Asia, including China, Japan, Taiwan, Vietnam, Thailand, and Myanmar. The name 'Bletilla' is a diminutive of the New World genus Bletia, reflecting a morphological resemblance between the two.

Morphology and Growth

Plants in the Bletilla genus possess pseudobulbs that are described as spreading corms, typically situated at or near ground level. Each pseudobulb usually supports several leaves that are pleated and can reach lengths of approximately 40 cm. The flower racemes emerge from the center of new growth before it fully matures, typically during the spring and early summer months. The flowers themselves display a range of colors, from white to shades of purple, and all recognized species share the characteristic of having four pollinia.

Tubers

The tubers of Bletilla orchids are distinctively horn- or claw-shaped, presenting a grayish-white or yellowish-white appearance. They are marked with concentric rings and feature brown rootlets, possessing a hard texture that makes them resistant to easy breakage. These tubers are a key feature of the genus's underground structure.

Species and Cultivation

As of recent botanical acceptance, the genus Bletilla comprises five recognized species, with several others having been formerly placed within it. The most commonly encountered species in cultivation and trade is Bletilla striata. This species is often labeled as 'Hardy Orchid' or 'Chinese Ground Orchid' due to its resilience and ease of growth. It was one of the earliest orchids introduced to cultivation in England around 1794. Bletilla striata is a deciduous orchid whose sympodial root system is flat and knob-like. Established plants frequently produce flower spikes before their leaves fully develop, bearing up to fourteen rose-mauve flowers with a ruffled lip, which are scentless and likened to miniature Cattleya blooms. These plants rarely exceed two feet in height and are surprisingly hardy, capable of surviving in ground zones as cold as USDA Zone 5 with adequate mulch. Unlike many tropical orchids, B. striata exhibits attractive foliage even when not in bloom. Other species, such as Bletilla ochracea, are less common but are becoming more available to collectors, noted for their distinct yellow sepals and petals with a red-marked white lip.

Cultivation of Bletilla species generally involves keeping them in pots of well-drained media to prevent water from accumulating around the roots during their winter dormancy. Watering should be done sparingly at the start of the growing season, as new roots may take time to develop. They prefer well-draining, consistently moist soils rich in organic material, avoiding conditions that are either too dry or waterlogged. While generally hardy, some species may require protection from severe frost. For potted plants, a frost-free location is advisable if winter temperatures drop below freezing.