I've bred many.
Breed an orange rose using a yellow and a red rose.
Breed a purple rose using two white roses.
Breed the orange and the purple rose.
Keep any red rose that comes from them, as that is your hybrid red.
Destroy or move any other orange or purple that spawn, as they don't have the proper parents, so remember your planting order with the orange, and the purple.
When you have two hybrid reds, plant them, and use fertilizer.
Time travel helps, as it can take a while to get your blue rose, but you WILL get it.
Once you have two blue roses, they breed very easily.
Also remember your hybrid red planting order, and disguard any red roses that spawn from your hybrid red.
They are useless.
Good luck! ^_^