Oh, LCL what a welcome sight! They're beautiful!
There is no true blue rose. It's been the Holy Grail of rose hybridizers for a century but there is a problem. There is no blue gene in rose DNA. So for decades breeders have been naming lilac, lavender,, mauve roses with "blue" names because that is as close as they can get to a blue color. In recent years, it is my understanding, that the Japanese have been working with gene splicing to introduce a blue gene into roses. The problem with that is that they cannot control where the gene expresses itself. They've had roses with blue stems, thorns, leaves and occasionally blooms. However, it is not stable so it may produce one blue bloom and then revert back to what ever other colors are in the genetic make up of the cross. So the true blue rose is still elusive.