Hi everyone. First time here. Hope to get some advice.
We have a sour cherry tree in the front yard that we planted 6-7 years ago. It is North Star variety. During the second or third year we get a handful of cherries from it, and that has been it.
The last 2 years it bloomed vigorously, and fruit started growing, looked healthy, and then suddenly fruit started to yellow and wilt. Eventually everything disappeared this way, except maybe 2-3 cherries.
This year things looked even better, but today I noticed the same process has started.
Any suggestions on what could be causing it and what I could do?
When I had a similar issue with my cherries
(flowered, fruit set, developed a bit, turned yellow and fell off in drove), I was told that it possibly was because of inadequate pollination. Yes, North Star is self pollinating. Often, having another compatible variety to cross pollinate will increase yield. In my case I have no room for more cherry tree. I grafted a couple more varieties to it .
I also suspected my cheery tree also suffered from brown rot blossom blight. The blossom blight, you need to spray fungicide at bloom time.
That sounds phoney… I could be wrong but flower buds are less cold hardy than wood. If it gets cold enough it would have damaged the buds themselves and they would have either failed to bloom or drop shortly after the freeze, not when the fruit was this far along.
Fruit set can be greatly affected by nutrient deficiencies. That means that it could also be the soil PH as it affects mineral intake.
Poor fruit set is common for me with plums. The fruit looks much like yours. It can’t hurt though to get a soil test to eliminate that from the equation. Most extension services offer the service. Wisconsin has cheap testing. Doesn’t matter if in state or not. They give directions on how to take sample online. MSU offers testing as do a number of private labs and all agricultural universities. Make sure to tell them what you are growing.
Plant another sour cherry near by. I had most of the fruit dropped on North Star until I planted Carmine Jewel. The idea was to remove North Star as soon as CJ starts producing. The first year they flowered together I got a huge crop on North Star and getting it every year ever since. Looks like “self-pollinated” North Star actually needed a pollinator.
I agree with @nkurz, this problem definitely needs to be investigated, if the tree does have a virus, adding other trees around this one as previously discussed will not help since the virus can easily be spread around. If the problem isn’t a virus then most likely adding more trees is the way to go.