My beloved Redbud has no buds = no flowers. I have heard that the buds emerge in September and were probably killed by the harsh winter, and also that the leaves will probably follow. I have done a careful thumb-scrape in a few spots, and yes, the branch is green. Is there hope? How long should I wait until I can be sure the tree has survived?
Trees like your eastern redbud (Cercis canadensis), although really hardy, may be damaged or even destroyed during unusually harsh winters, where temperatures are very cold, drop quickly or fluctuate from warm to very cold. Late spring and early autumn frosts tend to do the most damage to active plant tissues that have not hardened off enough to tolerate the cold.
All parts of the plant can be injured, including flower buds, vegetative buds and stems. Damage begins with the softest, actively growing tissues, such as new leaves and tender shoots. Stem damage may not be evident until active spring growth starts.
Experts advise that redbuds that have had twig and bud kill, or that have less than half of their lateral branches killed back due to a harsh winter, may recover with drastic pruning over several growing seasons. Never cut back more than one-third of the redbud’s branches. Watch for foliage recovery as opposed to focussing on flowers. Your tree may not look as lovely for the next few growing seasons, but should recover and fill in nicely.
I don’t know how big your tree is but if it is not too large, you might consider protecting it against future winter deep-freezes by providing protective cover during cold snaps. This could be done by carefully wrapping it in a Burlap coat.
Patience is a gardener’s best friend and it may be that you looked too soon, so please wait before doing anything radical to this tree. The buds generally need time to swell as the spring warms up before breaking out into bloom. This spring was slow in coming and many trees are just that little bit later in waking up after their long winter dormancy.