Late Blooming Tree, Root Stimulator Application

Question: Hello, I have an amur chokecherry tree in my backyard that is very late in blooming. Last year it got rust and lost its leaves a couple weeks early. This year, it budded, but the buds didn't open all the way. A week ago (May 31) I applied 1.5 gallons of a diluted root stimulator solution (Bonide Root & Grow) that seems to have helped things along a bit, but it's still slow going. How long should I wait before applying more root stimulator?  I should add the tree is approximately 12 feet tall. It has multiple trunks at chest height, for an approximate diameter of 3.895 inches (using the diameter of the largest trunk plus half the sum of the other two diameters). In my research, I found recommendations to apply stimulator every 4 weeks, but I also saw that you should add a gallon of stimulator solution for every inch in diameter. So far I've applied less than that.  I've included some photos of the tree before and after.  Thank you, Mike

responder: Gooseberry Peter  Replied June 12, 2023, 2:46 PM EDT
response: Hi Mike,  Thanks for the great question. How does your tree look now? I have noticed a lot of the amur chokecherry around town has been slow to bud and bloom this year. It might just be the late/cold spring that we had. If it is still looking stunted let me know and we can explore options. Thanks!

responder: The Question Asker Replied June 12, 2023, 4:52 PM EDT
response: I gave it another round of root stimulator Friday evening. The leaves are really struggling to come out. The ones on the lower branches are a little farther along than those up top, but that makes sense since it’s less distance from root to leaf/branch.  It looks like the tree is sending the majority of its energy  to the berry buds. It’s alive, but it’s not happy, which is odd because it typically loves where it’s at (plenty of sun, etc.).  All the Amur chokecherries in the neighborhood are in full bloom, and the shrubs & trees around it are doing well (the azaleas are late, but that’s likely due to temps). That’s a long way of saying “not much change/improvement.” Thanks, Mike

responder: The Question Asker Replied June 12, 2023, 4:57 PM EDT
response: By “another round of root stimulant” I should clarify that’s another gallon of the diluted solution (3 tbs/gallon).

responder: Gooseberry Peter  Replied June 12, 2023, 9:10 PM EDT
response: The buds look healthy even though they are behind schedule. If they continue to come in with normal shape and color that's good. In the absence of any bark or root damage, or sign of pest/pathogen, there isn't much I can recommend other than keeping it well watered and maybe using a slow release fertilizer to try giving it a nutrient boost. Could be just needing some extra support while it sorts itself out. If the buds (leaves and flowers) start to look abnormal (aside from delayed) or if you see anything on the bark (like cankers), that might indicate a pest or pathogen. Any possibility it was exposed to an herbicide this year or last year?

responder: The Question Asker Replied June 13, 2023, 12:40 AM EDT
response: Last year I sprayed it with fungicide (Earth’s Ally Diseaee Control) when it got rust and put two spikes of Jobe’s fertilizer in the ground (the recommended dose for the size of the tree) hoping that would help it out. should add that i also sprayed what I could reach with Neem’s oil and gave it some fertilizer for flowering shrubs/trees a few weeks ago.  Given how much it liked where it was and had tremendous growth, I’m curious if the spikes threw the ground chemistry off, or if the tree is just reeling from the effects of the rust.  I read that can make a plant lose its vigor, but I can’t find much on what it dies to trees post infection/leaf loss. The grass and everything else in its vicinity are growing normally (within a 6-10 ft radius are 2 lilacs, 2 azaleas, a rose bush, an hydrangea, 2 mock oranges, a crabapple tree, and a Rocky Mountain maple sapling).  I had a guy from Tall Trees come out and he didn’t see any signs of disease and thought it was likely root related somehow. He mentioned that roots could get knotted and tangled. Does that ring true in this case? Anyway, he was the one that suggested the root stimulant.  At this point I’m not even sure whether the flowering fertilizer or the root hormone are what worked. And I’m afraid if I throw any other medicine at it, I will do more harm than good.

responder: Gooseberry Peter  Replied June 13, 2023, 8:27 PM EDT
response: It sounds like you have done all you can do at this point, and I agree that further treatments may do more harm than good. I wouldn't expect the roots to be tangled up unless there is some kind of barrier to their growth that they are butting up against under the ground. If that's the case you would have to move the tree or remove the barrier. It is possible that things are just off to a slow start because of the stress from last year plus a long winter. I would keep an eye on it and let it recover. Keep it watered. If you notice any change in symptoms, let me know and I can look at that. Hope things bounce back!

responder: The Question Asker Replied June 13, 2023, 9:51 PM EDT
response: Re: the roots, there isn’t anything in the immediate vicinity that would be blocking enough to cause issues.  I just went out and checked on it. The flowers are trying to open up (transitioning from green balls to white). The leaves aren’t doing much but at this point I’m not expecting them to. I’ll hold off on additional treatments for a while and see how it does. Given the weather this summer I’m not worried about it getting enough water.  Thanks for all your help!