In reality, it should be spread out more, and not just a week. You would also have to squeeze early in between extra early and mid, and that isn't going to all happen in one week normally. But, it depends on where you live and the weather conditions. An extra early may bloom in March for some people, but not until July for others. Because of that, I didn't pay any attention, really, to bloom times. Extra late was a little more important for me, but then some people run the risk of not getting many blooms because snow is flying by the time the plant is ready. I believe that the bloom times are all coming from the hybridizer, and what the plant does in their own garden. Once it leaves their garden and moves to a different part of the country, it can change due to the zone the plant moves to. Peak bloom was always later in July and then in August for me, but for many people, it was much earlier. It's really confusing!
