Asked July 21, 2021, 5:57 PM EDT
Anoka County Minnesota
Thanks for the question.
Well, this is an interesting puzzle! Four different species of trees and some bushes all died between last fall and this spring. My first question is going to be a rather stupid one. How do you know they are all dead? Brown foliage or even no foliage at all, does not necessarily mean the plants are dead. There are two pretty quick ways of determining this. First, when you break off a twig or branch, does it “snap” quickly. If it doesn’t that twig is not dead. Secondly, if you lightly scrape off some of the bark from a twig or branch, what color is the underlying plant tissue? If it is green, the twig is alive. If it is brown or yellow, the twig is dead.
When we see many different species die in a rather short period of time, it is unlikely that it was caused by insects or a specific plant infection (fungal, bacterial, viral). Some environmental effect must be involved. Your herbicidal spraying comes to mind. Even if you did this spraying away from the planting, herbicidal drift might have occurred. This often happens when the temperature is high and there is some wind. The spray volatilizes into small droplets that are carried by the wind to other plants. This could take place even over a distance of 30 feet or more.
I suspect that you have had your drain field in its current location for at least a few years. So I can’t understand why it should suddenly be a problem unless the septic system failed. If this did happen, I would think you would be aware of this.
It is difficult to know how to prevent this unless we know what is the cause. Soil analyses could be done but they generally measure nutrient (nitrogen, phosphate, potash) levels and soil pH. They would not determine any toxins that might be present.
Another possibility is that this planting and bushes had been exposed to road salt over the winter. This assumes the plants were fairly near a road. From what you wrote, this does not seem a likely possibility.
So I keep coming back to the possibility of herbicidal drift. So when you said the trees died abruptly, did that mean they never developed any foliage at all this spring, or did it mean that they developed spring foliage and then things took a turn for the worst?
Looking forward to your thoughts and responses. Thanks for asking us your questions.
Thanks for getting back to us. If the ash, maple, and oak had some green branches on them, that would indicate that each of them each had some active roots. I am hesitant at this time time to suggest to you that they should be removed. Besides this time of the year (late July 2021) is not a good time to plant replacement trees. For these three trees,I would suggest that you prune off all of the dead branches. However do this pruning by starting at the ends of the branches and remove small pieces at a time, working your way back to the trunk. For each cut look at the ends. Sometimes a branch is dead at the end but not towards the trunk. In other words, for the dead branches only remove those sections that are dead. Keep up daily watering.
It's good that we can eliminate the possibility of road salt. The Preen that you applied is also a non-factor as it would not have affected the trees. Often ash are grafted trees. The suckers that you see coming up from the base may be from the grafted base. These suckers can just be nipped off.
It sounds as if your weed spraying was done in an acceptable manner. However I don't think that it can be completely eliminated as a cause. The septic tank cause was a long shot on my part. You could have someone out to inspect the system, but that will be your decision.
For the time being it just may be wait and see. If towards fall nothing has improved for the better, please get back to us so we can revisit your situation.
Thanks for using our forum.
Thanks for getting back to us.
Your hackberry may just be experiencing sun scorch. This has been very common this season. This occurs under conditions of high temperature, intense sunlight, and drying winds. This can cause leaves to yellow and even become brown or black. Sometimes the leaves curl at their edges. Unless wide spread in the hackberry, there should be no significant damage to the shrub. Just keep watering it. DON'T add any fertilizer. If not this fall, I suspect that it will look much better in spring 2022.
Thanks again for asking us the question.