Fruiting Plants Blooming Out of Season

Last summer I lightly pruned my apple espalier to remove some wayward growth.  A few months later, in late summer, I was surprised to see apple blossoms on the tree!

This November, I was surprised to find two of my blueberry plants absolutely thick with blossoms. The photos don't do them justice.

What is going on with these plants blooming out-of-season? And more immediately, should the flowers be removed?  Should winter pruning be deferred?

In making a decision whether to remove the flowers or to prune, it is helpful to understand why the plant may be blooming out of season.  Spring-blooming trees and shrubs form their flower buds in late summer. Environmental stresses, such as heat or drought, can induce a temporary dormancy.  The plants may have set their flower buds as usual but go dormant when stressed.  After the heat wave or drought conditions end, dormancy ends.  If conditions are just right for flowering, the plant will flower just as if were springtime.  But there may not be enough time for the fruit to mature, particularly in frost-prone areas.  Luckily, with fruit trees at least, the trees do not usually expend all of their blossom buds at this time, so there should be more flowers in the spring and yields should not be significantly affected.

In the case of the apple espalier, I had lightly pruned the apple espalier in the summer to restrict wayward growth.  For example, pruning foliage on new shoots can help prevent ripening fruit from being shaded from the sun.  It also encourages fruit buds to form.  We then had a heat wave, which may have stressed the tree into a temporary dormancy.  I don't know whether the summer pruning or the subsequent heat wave or a combination of the two, resulted in the apple espalier blooming.  There were only a few blossoms and clearly not enough time for any apples to ripen before winter, so the decision to remove the blossoms was fairly straightforward. 

Blueberry bushes care typically spring bloomers.  They can produce so many fruit buds that their berries are undersized; pruning the bushes can prevent overbearing.  Most references recommend removing flowers from first-year plants to prevent them from bearing at all so that the plant can grow more fruiting wood.  Mature plants are pruned to remove weak or dead shoots and to keep the plants productive.  The plants are usually pruned in late winter when fruit buds are visible. 

But here it was early November and my blueberry bushes were swarming with blossoms! I didn't know whether the plants were merely setting fruit for an extremely early spring crop or whether they were blooming out of season and the fruit wouldn't mature.  Should I prune or not? 

Last spring, I repotted one mature blueberry plant into a bigger pot with another new blueberry plant last spring.   I consulted with our knowledgeable Master Gardener Program Coordinator, Jennifer Baumbach, who knew just the right person to ask for more information.  Given that the plants had been repotted this year, and we had warmer temperatures than usual later this year, it turns out the plants might just be confused.  I decided to remove the flowers now and then to prune the plants later in the winter as normal.  I experimented both with stripping the blossoms off the brunch and lightly pruning certain branches to remove 8-10” of a blooming branch all at once.  We will see if either approach makes a difference.  But, because I'm a little bit of a softy (sometimes) and I couldn't bear the thought of removing all of those beautiful blossoms, I left a blooming branch or two (or three?) just to see what happens!

Apple blossoms. (photos by Erin Mahaney)

Blueberry flowers.

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