Tree Fruit Newsletter — May 19, 2025
Full Bloom Conditions
Return bloom appears adequate in most apple blocks at Highmoor Farm. Some trees of Honeycrisp have sparse bloom intermixed with trees that have good return bloom. Honeycrisp and most other varieties are in full bloom today. Cherries and early blooming apples are at petal fall.
Pollination conditions have been good in early blooming varieties, but bloom and pollination are still underway in Honeycrisp and other late varieties. The cool temperatures in the forecast for the Augusta area do not look favorable for good pollination during the remainder of full bloom. At Highmoor Farm, I observed adequate populations of wild bees working blossoms last week, but less than the average number of bumble bees. For orchards that rely on honeybees, there may be sufficient pollination after one day of strong bee activity. Hopefully, this has occurred for the king blooms that were open in the last few days.
Cool temperatures are also unfavorable for chemical thinning. The long-range forecast, nine days from now, indicates a rise in temperatures that will be better for chemical thinning. When warm weather returns, I anticipate that mild to moderate chemical thinning would be best for orchards that have less than the normal amount of bloom or less than ideal pollination weather. Orchards that have both scenarios co-occurring should still receive a chemical thinner application to ensure adequate return bloom next year, and also, that fruit set is in clusters of 1 or 2 fruit rather than 3 to 4.
Here is the link to the New England Tree Fruit Guide section on chemical thinners for apple trees: Chemicals for Apple Thinning – New England Tree Fruit Management Guide
Peaches are at petal fall. I am expecting good fruit set on many varieties and have been blossom thinning these trees by hand to take off 30 to 50%. It takes about 3 to 5 minutes per tree which is preferable to 15 to 30 minutes per tree that will be needed if I wait till June to thin after fruit set. Our trees are on the small side, so more time will be needed for standard-sized peach trees. If you applied Accede, it should reduce the crop load by about 50%, so some follow up hand thinning may be needed later.
Renae Moran
University of Maine Cooperative Extension: Tree Fruits
PO Box 179
Monmouth, ME 04259
(207) 933-2100
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