Hello everyone,

I'm just west of Portland, OR and have several mature sweet cherry trees that have not produced cherries for many years (they produced very well for the first 10 to 15 years). The trees are 28 years old and are between 30 and 35 feet high. They most likely have multiple problems--leaves have a yellowish tint and tend to be crinkly. Some leaves have "gunshot" holes in them. Leaves start falling in September and are off by the early part of October. Also, the density of leaves has been decreasing. The trees seem to initially set some fruit, but they fall off quite rapidly after reaching a size of ~ 1/8 to 1/4 inch.

I have begun a colony of orchard mason bees this spring but they didn't help.

I have not been spraying these trees. One reason is because they are so big. I'd appreciate any comments regarding:

1) how I could get the trees healthy

2) can I prune these trees to a manageable height, e.g. 20 feet? Can they be pruned during the summer. Can I prune them to 20 feet in one summer?

Any other suggestions would be appreciated.

Thanks very much,

Jerry

Hi Jerry... regarding question #1, I'd have to do some research to pin down the decline of your cherry trees. It sounds like a "classic case" of something ~ But I've been a few years now without "my" cherry trees and have forgotten most of their enemies. I know there was a reason I'd spray mine with copper in the fall - and your description sounds like it. Maybe someone else might know it off the top of their head?

Question #2: I suspect pruning back 10 to 15 feet would work. I've done some very heavy pruning on a "wild cherry," not caring whether I killed it or not, and its thrived! Seems you'd loose most of the fruit spurs - but then they're not producing anyway...

I know you can prune a healthy tree during the summer: remember that you're "robbing" it of its ability to resupply its root system. That's a good way to bring an aggressive tree into "balance." But in this case, sickly trees - I wouldn't advise it. It sounds as if they'll need all the "food" they can accumulate simply to survive.

Personally, this is one of least productive seasons I've seen ~ Our never-ending-spring looks to have fed & spread fungus and assorted diseases from Apple trees, to native Maples, and everything in-between! With most plant leaves distorted and struggling, while they've waited for sun & heat, this ugly Spring's left a poor fruit-set and the proliferation of opportunistic diseases spread and fed by moisture. It's got me looking to other projects; and leaving the trees to disease Less thinning / harvesting - more pond care & firewood gathering !

Keep us posted, Viron

Jerry
Problem 1
Yellow crinkly leaves, look for aphids, this may be the problem.
Problem 2
Shot hole fungus. This year especially and most years, this is a problem in our moist spring weather. Any fungicide will do, suggest Sulfur or copper.
Problem 3
No cherries. Cherries are susceptible to brown rot which attacks the flowers. Again, fungicide for a solution.
Problem 4
Trees too tall. Prune cherries only when the weather is going to be dry for several days after pruning. The general recommendation is to remove no more than 30-35% of a tree at any one time. Reason–there is a direct relationship between the root mass and tree mass. Think that the amount of tree removed that amount of root dies.

Look for gummy or brown/black pitch on the tree. If you find this it is a systemic (inside) bacterial infection (gummosis). If there is a large amount found the trees are probably on there last roots (legs).

Hope this helps.

Ted