Percy Wiseman normally blooms midseason which is probably around May 10 where you are I am guessing. If it was raised in a greenhouse or a more southern climate, it has been forced to bloom earlier so the garden centers can sell it. So it may be headed for an early bloom. Once it blooms the bloom should last for about 10 days though over 2 weeks is not uncommon and 3 weeks is possible.

There are lots of variables. Cold weather and shade will slow down blooming. Hot weather and sun will speed it up. Once it blooms, the same is true. Cool weather and shade will extend the bloom and hot weather and sun will shorten the period of bloom. Severe weather can reek havoc on a blooming plant.

Good Luck!