Problem getting fruit from cherry trees
I have two well established cherry trees in my back yard, right next to each other. They are different varieties. When I moved in there, I got great cherry production for many years, but because the trees were so big, I couldn't get to much of the fruit. So I had them professionally trimmed. They pruned but also cut tops so most fruit would be more in reach w/ ladder. The arborists said it would be 2-3 yrs after this trim before we'd see the fruit production again. It has been about 6 yrs now. We get lots of blooms, but then the tiny green baby cherries just shriveled up and fell off after time each season. We rarely yield more than 6 cherries, total. Last year we tried mason bees, but it didn't help. We have more bees for this spring, but are wondering if we are missing something. Did we do something permanent by having the trees topped? Any other ideas? Do you know best time to put the bees out. Thanks.
The first few years of reduced fruiting was likely related to pruning and rejuvenation but there shouldn't be long term effects. Sounds like the tree produces plenty of blooms, but that there is a pollination issue which is causing the fruit to drop. Cherry fruit drop, also called June Drop, can unfortunately be a common occurrence. (My own cherry trees have produced about ten fruit the last two seasons, as well!) The exact cause is difficult to pinpoint but can be related to lack of pollination, lack of fertilization, incompatibility, nutrient imbalance, winter injury, frost damage around bloom, and/or high temperatures during bloom. Some of these issues are out of your control (temperatures, etc.) but you can make sure your trees are properly fertilized and given other TLC.
Using mason bees to help assist pollination is a good idea because they are active in cooler spring temperatures (unlike other pollinators like honey bees). OSU Extension is working on a publication specifically on mason bees in the garden-look for this to be published in mid-March. Mason bees will be active when temperatures get to 50-55F for a few days in a row (this can be between Feb & March depending on what kind of spring we're having).
Please let me know if you have additional questions. You can reply to this email or feel free to contact the OSU Extension Benton County Master Gardeners as well.
Thanks for using Ask An Expert!