Vanda X Herziana ‘Blaue Donau’
The hybrid is one of the older ‘classics’. It was derived from two species that are probably the most widely grown members of the genus in Europe and ones found in every large collection and botanical garden.
The first is Vanda coerulea, a cold-loving species found in mountains at elevations of 700 to 1,700 m (2,350 to 5,650 ft), in the Himalayas, Burma and Thailand. This epiphytic orchid is a large plant up to 1.5 m (5 ft) high; its stem is covered with horizontal leaves about 25 cm (10 in) long and 2.5 cm (1 in) wide inbetween which grow numerous aerial roots. Theare blue — a very unusual and valuable colour amongst orchids — and measure up to 10 cm (4 in) across. The second parent is Vanda tricolor from Java and Bali. It is equally large, with longer leaves but shorter flowers which, however, are beautifully coloured — the lip is violet purple, the remaining segments mostly yellow with striking red-dish-brown markings.
Vandas and their hybrids are nowadays cultivated chiefly in Hawaii, Thailand and the United States of America for the cut-flower trade. The famous hybrids were raised at the Mandai Gardens in Singapore, where other genera of the subtribe Sarcan-thinae, such as Rhynchostylis, Renanthera and Aerides, were also used in subsequent crossings, yielding hybrids with magnificent flowers in the characteristic muted pastel shades. Though originally epiphytic species, they are often grown in pots and in the tropics even freely in the ground, where they do very well.
Vanda hybrids are not particularly difficult to grow, even in the home. They require ample light (only very light shading against direct sunlight) and find the temperature of most modern homes congenial. During the growth period they should be watered liberally and given ample doses of feed. During the winter rest period theshould be kept only slightly moist so it does not dry out. They will be satisfied with a standard light compost for epiphytes (see the section on laelias).