For rose shows, there is such a bloom that is called “exhibition stage”. Think of the perfect high centered rose. This is exhibition stage for a Hybrid Tea, and this is what the judges are looking for. The rose should be one-half to two-thirds open, with a high center and petals unfurling in a circle. Exhibition stages are the same for Hybrid Teas, Grandifloras, Miniatures, and a few single Floribundas. Many Floribundas look better as a spray, which means that there are several blooms on one stem, and the blooms are more open. The spray will do well in the show if the blooms are symmetrical and balanced. You can also enter roses that are fully open with the stamens showing.
So when cutting your roses for the show, either the night before or the morning of, consider the stage of the bloom, and how much it will open before it is judged (which will be 10:00a.m.-12 noon on Saturday.). It is a judgment call; you know your roses and how long they stay nice in a vase in your home. That knowledge can help you with this decision. Example of a rose that will not work at a Rose Show is Mardi Gras. It looks great in the garden, and the color pops against the green foliage. But when cut and put in a vase, it wilts within an hour or two. So it is not a good specimen for the rose show.
Utah Rose Society