When is the best time to have someone prune back this tree as it is taking over my small yard? I live in Prescott Valley, Az.
During my research I read they can be pruned in spring or anytime of the year. Summer pruning would be more for light pruning such as removing suckers, damaged limbs, and thinning the canopy. Here is more:
https://extension.umn.edu/planting-and-growing-guides/pruning-trees-and-shrubs
https://www.gardeningknowhow.com/ornamental/trees/catalpa/catalpa-tree-planting.htm
https://aggie-horticulture.tamu.edu/newsletters/hortupdate/2008/jul08/Catalpa.html
The flowers and leaves look exactly like a catalpa tree but there is no central trunk, just new sprouts from branches on the ground. Central area looks like dead black canes. I can find nothing about catalpa growing as anything other than a tree
It's possible there was a tree at one time, but now only suckers are growing.
I want to use a growth inhibitor on it as its getting too large for my yard and battling with a bush next to it. Can I get your thoughts on doing so and perhaps a recommendation on product? TY
I don't think that I would recommend growth inhibitors in this case. You would need to obtain the correct chemicals specific to the tree, while trying to prevent it from coming in contact with specimens nearby. I recommend growth inhibitors in very controlled situations.
In your case, This extraordinarily large tree might be best removed by a professional in your area. You could try your local extension service. They may have a few suggestions for people that can help you to remove the tree in your area.