True blue in orchids is very rare as in most other flowering plants. There has been a lot of work in hybridizing to produce these flowers and to some extent progress has been made.
The Vandaceous hybrids currently in vogue come very close to achieving this color. Most of them are descended from Vanda coerulea which is known as the Blue Vanda. This species is native to India, Burma and Thailand as an epiphyte. It requires a dry season in the winter and full sun during its growing season. The flowers are large and long lasting. One of the best known and easier to grow hybrids is Ascda.. Princess Mikasa. This Vanda comes in a number of colors, but blue is one of the best selling. Another Vandaceous variety with a true blue color lip is Rhynchostylis coelestis. This is a great little plant which takes up much less room than Vandas.
Another genus which has blue in the flowers is the Dendrobium. There are many shades, although none as true a blue as the Vandas. There are colors ranging from a purple-blue to slate blue. Many of these are indeed very attractive. There has been quite a bit of interest in the breeding of blue flowers and we should expect to see many more hybrids in the future. In the cut flower trade, which uses large numbers of Dendrobiums, flowers are dyed to produce colors from turquoise to dark blue and all shades in between. They are quite popular in cut flower arrangements and for decorating.
Cattleya is another genus where there is much interest in producing blue flowers. There has been much breeding done to produce a blue Cattleya, mostly based on the blue forms of C. gaskelliana, C. labiata, C. mossiae and C. warneri. The blue colors produced so far are really a very pale imitation of the blues available in Vandas. Some people doubt that there is really any blue at all, but rather a pale washed out mauve. Here are some examples blue cattleyas from the Santa Barbara Orchid Estate. There is still work ongoing, but so far a truly blue Cattleya with striking color has not appeared.
Look around at the offerings of various vendors for a blue that appeals to you and give these plants a try. One of the new hybrids might just turn out to be the blue we’ve all been waiting for.