Geography and distribution
In the wild, Vanda coerulea grows on exposed deciduous trees (primarily oak) at elevations of 900–1500 m. It has been recorded from India (Assam, Arunachal Pradesh, Meghalaya, Nagaland), Nepal, Burma, northern Thailand, and southern China (Yunnan), and is also likely to occur in Bhutan, Laos and Vietnam.
The striking blue flowers of Vanda coerulea are its most recognisable characteristic, with blue pigmentation only seen elsewhere in this genus in V. coerulescens, V. tessellata, and V. testacea.
The leaves are leathery and strap-like and attached to prominent leaf sheaths (part of leaf stalk that covers and rises up from the stem). The flowers are around 13 cm across and notable for their small lip (labellum), approximately 2 cm in length, an unusual characteristic for this genus, shared only with the similarly pigmented, closely related, but much smaller flowered, V. coerulescens.
The flower spikes of V. coerulea are occasionally branched, and bear more flowers than is usual in this genus (20–30 per plant, on multiple flower spikes). All characteristics plus the species’ cold tolerance (due to the elevation of its native habitat) make it highly desirable to orchid hybridisers.
Pink and white forms also occur in nature – the white forms being the most pure white flowers found in the genus.
Vanda coerulea flowers (Photo: Phil Cribb)
Kew’s research into the genus
The molecular phylogenetic analysis (a DNA-based ‘family tree’) of the genus Vanda has been the subject of a PhD project at Kew and will form part of the monograph on the genus, to be published shortly. Recent molecular work at Kew has shown that this species is more closely related to another blue vanda, Vanda coerulescens, than to any other Vanda species – a relationship not previously considered.
Threats and conservation
A number of factors led to Vanda coerulea being placed on CITES Appendix I in the 1970s. It was considered extremely rare in the wild, having only been recorded in the Khasia Hills of Assam, where it was over-collected and put at further risk by local charcoal production using the oak trees on which it grows.
Its geographical range is now known to be wider than originally thought, and it is relatively common and widespread in the Himalayan region. Consequently it has recently been removed from CITES Appendix I, although it faces continued threats from illegal wild collection and habitat destruction and the species remains on CITES Appendix II.
Vanda coerulea is a spectacular ornamental and widely used by orchid breeders to produce a range of hybrids. Recent laboratory research indicates that extracts from V. coerulea may have potential use in anti-ageing skin treatments.
Growing in the wild at relatively high elevations for this genus, Vanda coerulea is adapted to low night-time temperatures and cannot be easily cultivated in tropical and subtropical regions. It requires high light levels to flower and may flower freely 4–5 times a year in optimal conditions.
The hybridisation of V. coerulea, particularly with the large-flowered pink and gold Philippines species Vanda sanderiana, formed the basis of modern Vanda breeding, which is extremely important in many countries of South-East Asia and Florida, USA.
This species at Kew
Pressed and dried specimens, and specimens preserved in spirit, of Vanda coerulea are held in Kew’s Herbarium, where they are available to researchers from around the world by appointment. The details of some of these, including images, can be seen online in the Herbarium Catalogue.
Blue vanda seedlings are being grown behind-the-scenes at Kew but are not yet big enough to be put on display or to flower.
Vanda orchids in Kew’s Tropical Extravaganza
The Tropical Extravaganza festival at Kew always includes a range of spectacular deep purple vandaceous hybrids that have Vanda coerulea in their parentage. The 2012 exhibition, which ran from Saturday 4 February until Sunday 4 March, included an archway comprised of vanda orchids.