Blue orchid?

[elissa]

That's funny, chulaorchids!

Ray, what a gorgeous photo. If I could only find one just like that and buy it...yes, just a few days before Christmas, orchidexpress :-)

[Jerry Delaney]

They tell me technically, there is no "true" blue orchid. Orchids lack the pigment 'delphinium' which is necessary to obtain the true color "blue". However, that being said, many of the suggestions and pictures on this thread are about as blue as they get. If you find one with a color that both you and he like, call it blue and run with it!

[elissa]

Interesting, Jerry. I wonder how they can be so blue if they lack the blue pigment...some kind of mutation? Anyway, I will look, and if I find a dealer who has one of the true blue orchids, I'll post it here.

[Ray]

This is a very brief summary, and I suggest going some google-work to get the "real" story, but there are apparently three types of flower pigments:

• Anthocyanins (pelargondin - brick red, cyanidin - blue/purple, and delphinidin - true blue, which is not in orchids). They are water-soluble and internal pH can affect how they are displayed

• Flavones - pale yellow, also water soluble

• Carotenes - yellow/orange/red - oil/fat soluble, and not pH sensitive

I suppose chlorophyll should also be considered a pigment too, as there are greens in blossoms.

My guess is the the "blues" we see are as a result of cyanidin at a certain pH.

[quiltergal]

I know that ph greatly influences how blue or pink hydrangeas appear. Stands to reason that may also be true for orchids.

[elissa]

Very interesting, Ray, thanks.

[Neverend]

Interesting, thanks for the explanation!

[GreggC]

blue, red or black in orchids.

[Ray]

Blue or black, that's true, but I think the anthocyanins are abundant in them.

[Andrew]

Originally Posted by Ray

• Anthocyanins (pelargondin - brick red, cyanidin - blue/purple, and delphinidin - true blue, which is not in orchids). They are water-soluble and internal pH can affect how they are displayed

Such a classification of anthocyanins based on colour is somewhat misleading as anthocyanins can produce both red or blue pigmentation depending on the amount of hydroxylation and the presence of the necessary cofactors. The 'magical true blue' delphinidin is also responsible for the red colour of hydrangea in acidic soils. Similarly cyanidin, which by and large produces red pigment in most plants eg a lot of red berries, occasionaly produces blues such as in cornflower, which I personally consider as blue as many of the delphinidin expressing plants. The lack of representation by other anthocyanins amongst blue plants probably has to do with the amount of hydroxylation necessary to produce a blue pigment and the stability of these pigment products. However, several plants are capable of producing honest blues using other anthocyanins.