VANDA & ASCOCENDA CULTURE
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There are over 50 species of Vanda, which are distributed from as far north as the Himalayas, through Burma, Thailand, the Philippines to northern Australia. Culturally this genus can be divided into terate, semi terate and strap-leaved. The strap-leaved Vandas are the most commonly grown in the UK and the two species most responsible for the modern strap-leaved hybrids are Vanda coerulea, which comes from the cool Himalayas, and Vanda sanderiana (syn.Euanthe sanderiana) which comes from the hotter Philippines. The hybrids are most commonly grown in Thailand, Hawaii and Florida, where the natural warmth and good light results in stunning flowers in almost every colour - blue being the most popular.
There are 3 main ways of growing these monopodial hybrids:
In open baskets, either plastic or slatted wood, which basically gives the plant something to hold onto, and allows wires to be attached to hang them?
The flowers will last 6 – 8 weeks and can be expected to flower 2 – 3 times a year.
Winter minimum night temperature: 15°C (60°F). A rise in daytime temperatures to 20°C will encourage growth to continue through the winter.
Summer minimum night temperature: 15°C (60°F). During the day the temperature can rise to 25’C or above, but good air movement must be maintained.
Probably the most important item in the cultural jigsaw. Vandas can stand, and like, full sunlight throughout the year except for the hottest and brightest days in summer. They can be grown in the same glasshouse as the Phalaenopsis, but with much less shade
Being epiphytic their roots attach themselves to tree branches and hang in fresh air and are specially adapted to absorb water quickly and store it in the sponge-like velamen which surrounds them. When the roots on these plants are white, they are ready for watering.
We grow our Vandas hung on wires, with their roots in the air, and water the roots everyday, until they go green. In vases, we fill the vase until the roots are covered, leave for 20 minutes then tip the water out, by which time they will be fully turgid and green. Repeat as the roots go white. Feed twice a month in spring and summer with high potash feed. Only feed when the roots are moist.
When Vandas are hung on wires or in vases, there is no need to ‘repot’. If you pot your Vandas, use very large, coarse bark based compost, and transparent pots, so the roots can receive plenty of light. There best time to repot is spring, when active growth is gaining momentum. After the flower have finished on a stem, cut it back to be tidy as it will not reflower from it, but will produce another spike from a leaf axil higher up the plant.
Culture information taken from the Growers and Buyers Guide to Orchids in the UK – 2013 (Golden Guide).
Photographs supplied by S. Pask unless stated.