🇹🇭 Habitat and Ecology
 
​Holcoglossum calcicola is a rare, small to medium-sized, monopodial epiphytic or lithophytic orchid. It is native to Laos, and Yunnan (China). The species name calcicola (meaning 'limestone-dweller') refers directly to its specialized habitat: it grows almost exclusively on exposed limestone cliffs, rocks, or large branches in dry deciduous or mixed evergreen forests. It is found at moderate elevations, typically around 500 metres. This orchid is adapted to periods of strong sun exposure and seasonal drought growing alongside other species such as Dracenea fragrans and Euphorbia.
 
​🌸 Description and Distinguishing Features
 
​This orchid is an evergreen perennial highly valued for its striking, waxy blooms.
​Foliage: It produces a short, compact stem with 4-6, fleshy, rigid, semi-terete (cylindrical) leaves that are often sharply pointed and arching. The leaves measure 27 -45 cm.
​Flowers: The spectacular flowers are borne on erect to arching spikes (racemes) that emerge from the leaf axils. The spikes measure c15 cm, emerge from just above the most recent root and typically carry a 2-6 blooms, appearing in spring and summer.
​Aesthetics: The blooms measure. 2 cm wide, are waxy, and spreading. The sepals and petals are white. The key feature is the lip (labellum), which is large, spurred, and yellow. The floral morphology is unlike other Holcoglossum species and resembles Papilionanthe.
​Ethnobotany: Due to its rarity and specific habitat, there are few direct ethnobotanical records for H. calcicola. However, related Vanda and Holcoglossum species in Asia have historically been valued in Traditional Chinese Medicine (TCM) and local traditions for their stems and roots.
​Differentiation: H. calcicola is distinguished from similar species in the genus by its floral and vegetative parts:
​Versus H. wangii: H. wangii typically has longer, thinner leaves and a different spur shape on the lip, whereas H. calcicola has shorter, stouter, and more rigid terete leaves.
​Versus H. amesianum: H. amesianum is a larger plant with less rigid leaves, often found at lower elevations, while H. calcicola is a true limestone specialist with rigid, whitish foliage.
 
​💧 Cultivation and Care
 
​Holcoglossum calcicola is a cool-to-intermediate growing orchid that requires specialized, arid conditions and high light.
​Light: Needs very bright light and can tolerate direct morning or late afternoon sun. High light is crucial for rigid growth and flowering.
​Substrate: It is best grown mounted on rough bark or limestone rock or potted in a minimal, extremely coarse, and free-draining mix of large bark and charcoal.
​Watering: Water sparingly during the cool, bright winter months. Water heavily and regularly during the warm growing season, allowing the roots to dry out rapidly between waterings. It is adapted to frequent drying.
​Temperature:
​Optimal Daytime Temperature (Growing Season): 21-27 C (70-81 F).
​Optimal Nighttime Temperature: A cool drop is necessary, ideally 12-16 C (54-61 F), especially in winter.
​Humidity: Moderate humidity (50-70%) with strong air circulation is vital.
 
​✨ Unique Features
 
​This orchid is a unique lithophytic specialist, highly prized for its rigid, terete, whitish-green leaves and its spectacular, large, waxy flowers. Its ability to tolerate high light and strong periods of drying makes it a hardy and distinct addition to the collector's warm-intermediate Vanda alliance collection.
 
​🏷️ Specifications
​Plant Size: Recently deflasked, plants are larger than expected at this stage. We estimate that they will be flowering in 1-2 years.
Plant Family: Orchidaceae
Plant Passport: A Holcoglossum calcicola B 140084 C [buyer to use number of the plant label] D GB