Why is my Flowering Crabapple tree not blooming?

Question:

We have had a Flowering Crabapple tree (not fruit one) for three years. The first two years it was excellent. This year it’s not blooming. It is not 5′ high and has buds. It is alive but there are no blooms.

Answer:

Jonathan Foster, Home Horticulture Outreach Professional

There are a few reasons your crabapple might not be blooming right now. This sounds like a small, young tree, so you probably haven’t been doing much pruning, but overly aggressive pruning can sometimes stimulate the tree to flush out vegetative growth rather than flowering. Additionally, insufficient sunlight can inhibit flowering, but it sounds like this isn’t the case for you since the tree bloomed the last two seasons. Based on your description, I don’t think these are the issue.

So, the most common and likely culprit is a late frost–if the buds have begun to develop from warming temperatures and then a hard frost hits, they can be damaged to the point of never opening. Sometimes this is obvious, sometimes it’s inside the bud. Unsurprisingly, this is something that happens to flowering plants all over Maine periodically because of our climate. If the buds you see don’t open, that’s probably what happened and next year the tree should recover.

Another potential impediment to blooming is excessive nitrogen uptake from nearby applications. Homeowners who heavily fertilize their turfgrass near a crabapple may run into this, and the extra fertilizer signals the tree to put its energy into vegetative shoot and foliar growth instead of bud development. If you don’t fertilize your lawn or if the tree is at a distance, this probably isn’t an issue. If this might apply, try to limit how closely you put down grass fertilizer.

As long as the tree looks otherwise healthy and leafs out normally, I wouldn’t worry about the long term prognosis. Please see our UMaine Cooperative Extension Bulletin #2058, Flowering Crabapples in Maine, for more information on caring for your tree.

Happy gardening.