JoAnne Skelly: Apple trees had no blossoms
A reader sent me a question: “We had an arborist trim our apple tree in March and this is the first year in at least 20 years that the tree had no blossoms. Is this situation common or did we do something wrong?” Neither of my apple trees had flowers this year, either. I had assumed a late freeze had caused this because often my trees bloom, then there is a freeze and the flowers wither and die. However, this year there weren’t any flowers at all.
Sometimes trees don’t flower because they are too young. This doesn’t apply in my reader’s case or mine. Or trees planted in the shade or that have soil issues may not bloom. Again, this doesn’t apply to my reader’s or my trees since they have successfully borne fruit in many other years. Another factor is that apple trees have specific chill requirements, meaning they need a certain number of hours during dormancy under 45 degrees Fahrenheit in order to bloom. I don’t keep track of this and now I can’t remember what this past winter was like other than wet. I don’t think it was unusually cold or warm. Did we have enough chilling days? I don’t know.
Overfertilizing, particularly with nitrogen, can increase leaf and wood production at a cost to flower bud production. You might think you don’t fertilize your trees, but they benefit when you fertilize the lawn around them. Overpruning also can stimulate excessive leaf growth. And, sometimes when we prune, we cut off the squatty ugly flower spurs, thinking we are cleaning up the look of a tree, when we are actually cutting off the soon-to-be flowers.
Fruit tree flowers are sensitive to spring freezes around 29 degrees and below from the time buds start to swell. Extreme temperatures below -15 degrees during December, January, February and March also can damage the future flowers.
Lack of pollination or poor pollination is a significant factor in lack of fruiting (but not blooming). For trees to bear fruit, healthy pollen must reach the flowers at the optimum time. Bees are the primary pollinators for apple trees, but bee populations are on the decline due to insecticides, cold weather, rain and wind.
Finally, if a tree had a heavy crop last year (as mine did), flower production can be limited or nonexistent. Thinning at the appropriate time in spring helps reduce this. For information, see https://extension.psu.edu/home-orchards-why-is-there-no-fruit-on-my-tree.
JoAnne Skelly is associate professor and Extension educator, Emerita at University of Nevada Cooperative Extension. She can be reached at firstname.lastname@example.org.