Cherries not ripening - Ask Extension
Hi Extension staff. We live in Denver with a big beautiful healthy cherry tree. For the past two years, it has produced at least 100 cherries. The ...
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Cherries not ripening #876652
Asked July 10, 2024, 11:55 AM EDT
Hi Extension staff.
We live in Denver with a big beautiful healthy cherry tree. For the past two years, it has produced at least 100 cherries. The earliest 10-20 cherries will ripen completely and be delicious. The remaining 80 cherries will start to ripen, get about half size and about half red, and stop growing. They will just sit on the tree like that until they shrivel up. Any idea why this is happening or what we can do about it? My guess is that the tree is overproducing and can't put enough energy into ripening all of them, is that a thing? Thanks for any advice.
Denver County Colorado
Expert Response
Yes, it could be that your cherry tree is aborting some of its fruit because the tree can't support the number of fruit on it. A younger tree, or a small tree will do this until there is enough leaf canopy and roots to support more fruit production. You could try manually thinning the tree in the spring and see if this helps.
Another reason is poor pollination conditions during bloom. Unpollinated flowers will start to form, fruit starts to grow but then stops. Cool, wet weather is sometimes to blame because insects are not active, or there could be not enough insects in the area pollinating. Check the shriveling cherries and see if there are pits in them. If not, if it's just soft tissue, then this is the problem.
Sour cherry trees are self-pollinating, but sweet cherries are not. So if you have a sweet cherry tree, and no other sweet cherries in close proximity, even with insects, you won't get pollination:
https://extension.colostate.edu/topic-areas/yard-garden/pollination-of-tree-fruits-7-002/?_gl=1
Other possibilities are plum curculio insect damage early which arrests fruit growth or bacterial canker, a disease that infects both fruit and leaves.
If you did not see any marking on the fruit typical of plum curculio, then most likely it is poor pollination due to cool wet conditions during the first part of bloom. Fruits grow a while, turn red and then drop. A few stick on the tree where they will eventually shrivel and turn black. it's not a disease problem.
Another reason is poor pollination conditions during bloom. Unpollinated flowers will start to form, fruit starts to grow but then stops. Cool, wet weather is sometimes to blame because insects are not active, or there could be not enough insects in the area pollinating. Check the shriveling cherries and see if there are pits in them. If not, if it's just soft tissue, then this is the problem.
Sour cherry trees are self-pollinating, but sweet cherries are not. So if you have a sweet cherry tree, and no other sweet cherries in close proximity, even with insects, you won't get pollination:
https://extension.colostate.edu/topic-areas/yard-garden/pollination-of-tree-fruits-7-002/?_gl=1
Other possibilities are plum curculio insect damage early which arrests fruit growth or bacterial canker, a disease that infects both fruit and leaves.
If you did not see any marking on the fruit typical of plum curculio, then most likely it is poor pollination due to cool wet conditions during the first part of bloom. Fruits grow a while, turn red and then drop. A few stick on the tree where they will eventually shrivel and turn black. it's not a disease problem.
Thank you,
The cherries is all have pits, and no blemishes. Is it possible that they are being pollinated by sour cherry trees and that’s making them be sour?
On Thursday, July 11, 2024, 12:19 PM, Ask Extension <<personal data hidden>> wrote:
Sweet cherries (Prunus avium) are the same genus as sour cherry (P. cerasus) but different species and it is unlikely that they would cross-pollinate if for no other reason than that they flower at different times.
The cherries in your photos look good and the stem growth increment also looks good. The only cherry in your photos that doesn't look good is the last one, the wrinkly one. However, I don't see any signs or symptoms of pest or disease; it just looks like fruit past its prime.
The cherries in your photos look good and the stem growth increment also looks good. The only cherry in your photos that doesn't look good is the last one, the wrinkly one. However, I don't see any signs or symptoms of pest or disease; it just looks like fruit past its prime.
