Walnut - Ask Extension
A few years ago, about six walnut (10'-20') trees sprouted in all areas of my natural yard in west Fort Collins. I do not see any in the neighborhood...
Knowledgebase
Walnut #877106
Asked July 13, 2024, 4:05 PM EDT
A few years ago, about six walnut (10'-20') trees sprouted in all areas of my natural yard in west Fort Collins. I do not see any in the neighborhood so I thought they might have been sumac as my yard also has those.
I have searched about thousand canker disease but cannot find any recent info. Is it worth letting them grow...along with my 20' volunteer ash trees?
Larimer County Colorado
Expert Response
Hi Ron,
Sure you can let them grow - since you're aware of Thousand Cankers disease. It's unlikely they will survive long-term; we've lost most/all of the black walnuts along the Front Range. (Shame, it's such a nice tree.)
The only concern would be if they were to fail, would they damage any structures? And do you have the ability to remove them if necessary? The research on walnut twig beetle and thousand cankers largely ended when Dr. Tisserat retired, but there was little control from insecticides.
As for the ash, if you plan to leave them untreated, the wood following EAB becomes very brittle and can break easily. There is more of a concern to leaving standing dead ash trees because of potential failure. If they are 20 feet tall, they could damage structures if they failed? It would be something to consider.
Also, the ash will continue to grow, so removal, when necessary, will increasingly be more expensive. If they are trees you want to keep for any reason, doing treatment would be worth condsidering.
Sure you can let them grow - since you're aware of Thousand Cankers disease. It's unlikely they will survive long-term; we've lost most/all of the black walnuts along the Front Range. (Shame, it's such a nice tree.)
The only concern would be if they were to fail, would they damage any structures? And do you have the ability to remove them if necessary? The research on walnut twig beetle and thousand cankers largely ended when Dr. Tisserat retired, but there was little control from insecticides.
As for the ash, if you plan to leave them untreated, the wood following EAB becomes very brittle and can break easily. There is more of a concern to leaving standing dead ash trees because of potential failure. If they are 20 feet tall, they could damage structures if they failed? It would be something to consider.
Also, the ash will continue to grow, so removal, when necessary, will increasingly be more expensive. If they are trees you want to keep for any reason, doing treatment would be worth condsidering.
