Plant Information

VANDACEOUS ORCHIDS

The Vanda Story
by Ros. Xerrie of Brighton Orchid Nursery

The Vanda genus is one of the most popular groups of orchids grown. Extensive hybridising has been done within the genus & with other genera to produce orchids of exceptional beauty. There are 3 distinct groups of Vandas which are easily distinguished by the shape of their leaves :-

Strap-leaf Vanda has rather flat, broad leaves growing close together, alternating on the right & left sides to give a beautifully symmetrical plant. The flower stem also alternate sides, coming from the axils of the leaves on the upper part of the plant.

Terete-leaf Vanda has cylindrical leaves, shaped like & about the thickness of a pencil on mature plants. Their leaves grow to 4 to 6 inches long & are sharp or blunt tipped, with their bases encircling the stem. The flower stems appear on the side of the stem opposite the leaf. They are sun-loving orchids.

Semi-terete Vanda is a hybrid between the strap-leaf & semi-terete Vandas & the leaves are somewhat in between. These orchids require bright light, & upon hardening can be grown in full sun, so are ideal for landscaping in frost free areas. They will reward you with multi-spikes of beautifully coloured blooms several times a year.

V. coerulea is the famous Blue Vanda species, much admired in its own right as well as its contribution to the Vandaceous hybrids. The line-bred species we know today are far superior to the original collected forms of yesteryear. The pure white form is extremely rare & a good clone commands very high prices, as does the delicate pink variety. This strap-leaf species occurs under sunny, cool conditions at high elevations in northern India, Burma & the north of Thailand. It flowers towards the end of winter & into spring. This species appreciates plenty of light with cool conditions. V. coerulea crossed with V. sanderana produced one of the most famous hybrids:- the large, flat blue V. Rothschildiana.

V. sanderana (Syn. Euanthe sanderana) is one of the most beautiful orchids known. It originates from a warm, humid, low altitude area of the Philippines. It has an impressive, full-shaped, well-balanced flower:- with the dorsal sepal & petals being a lovely rose pink with the lateral sepals being yellow/green suffused with mahogany red & marked with a network of brown. This quite large flower bears a small crimson red lip, with a squarish middle lobe & side lobes that form a little cup under the tip of the column. The Alba form of this famous species has proven very difficult to find in its habitat. With the development of efficient seed germination in the laboratory, this much sought after variety is becoming more available. The lovely rare Alba form can be quite difficult to grow, as it requires bright light & does not appreciate temperatures dropping down below 15 degrees C.

V. denisoniana is a very attractive Vanda which has many different colour variations from clear yellow, green & orange-brown. The clear yellow & rare Alba forms are much sought after. This species grows at high elevations in Burma & north-eastern Thailand. The flowers are 6 cms across, waxy & of a heavy substance with a delightful perfume. This characteristic carries on to its progeny.

Vandaceous Intergeneric Hybrids There is a real fascination for Intergeneric Vandaceous Hybrids. These miniature Vanda like plants are produced by interbreeding the various genera of the Vandeae to produce new genera like Opsistylis, Renanstylis, Rhynchovanda, etc. They come in all colours of the rainbow & have earned a permanent place in every orchid collection. The Vandaceous intergenerics have been found to be extremely hardy plants which can tolerate a great variety of conditions. The following are some of the more popular genera used :-
Ascocentrum This is a small genus closely resembling Vanda which breed freely, although not naturally with the latter genus to produce the ever popular Ascocenda. The Ascocentrum resembles the appearance of a small strap-leaf Vanda with erect inflorescences of many small brightly coloured flowers facing in all directions. The blooms are extremely bright & even in colour. Each flower is flat in form & has a long spur which points vertically downwards. This delightful genus is found growing in the deciduous trees in northern Thailand, Burma & the Himalayas.

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The Vanda genus originates from Southern India, Papua New Guinea and Australia, China, Taiwan and the Philippines. There are approximately 50 species of Vanda, mostly large, fragrant, monopodial orchids with thickened roots and stems, and either terete or semiterete leaves. They require intermediate to warm conditions with regular watering and fertilizing as they do not have a pseudobulb for storing nutrients. They are best kept at an even temperature, if possible, as sudden fluctuation cause leaf straining and/or dropping, particularly of the lower leaves and smaller weaker flowers.

S Knight

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