If you're talking about one of the methods that produce the lowest value red rose that can produce a blue rose (1110), those red roses have only a 1 in 64 chance of producing a blue rose so there's no way to know for sure until you get really lucky and get the blue rose. So all you can do is keep breeding. If you're getting orange roses, you're probably on the right track. If you're using the orange + purple method to get hybrid red roses, then half of your red roses will have no shot of producing a blue rose so you'll just have to breed a lot of those hybrid reds and hope you hit on two good ones. If you're using a more reliable method to get hybrid red roses like the Asteriation 1010 red + seed yellow or 1011 pink + seed yellow, then you know your hybrid reds are good and you just have to keep trying. You can improve your odds by taking any red, orange, or black offspring from those hybrid reds, cloning them, and breeding them with their clones to potentially have genetically superior pairs with a better chance of producing a blue rose.