Last fall (September and October), I noticed healthy specimens of pear, apple and crabapple blooming. The only times I have seen such plants blooming outside of their normal seasonal patterns are when they are acutely distressed. What would have caused such a strange blooming cycle on otherwise healthy plants?

While most trees only bloom during their normal seasonal time, healthy mature trees do have the ability to set a flower bud early, known as the king flower bud. When the king flower bud has a nice, sunny fall day it will bloom. The secondary flower buds will bloom only after they have gone through their normal winter rest period.