Q. We have a large mimosa that's growing in the middle of a grove of other trees on a slope. We're not ready to cut it down but we don't want any more little mimosa seedlings all over the yard. Is there a way to kill this tree without using herbicides? We don't like to use chemicals for anything unless we have to.
A. Mimosa, as you know, is a very vigorous tree (and iinvasive in many areas). You can try one of these girdling techniques:
Using an ax or hatchet, chop through the outer and inner layers of bark all the way around the tree trunk, creating a "ditch" or groove that's 1-1/2 inches deep (on a small tree, at least 1/2-inch deep) and at least several inches wide (on a small tree, only a couple inches wide will be enough). Creating this groove will require your chopping both upward and downward. You're in effect girdling the tree, but instead of simply slicing into it, you're creating a wide inactive area that disrupts the flow of sap. Use the above method, but chop downward and slightly inward, leaving a "frill" of bark and wood curled under the wound. Using a chainsaw or handsaw, make a cut 1-1/2 inches deep (on big trees) all the way around the trunk. Then make a second cut two to four inches above or below the first.The tissue above the cut will eventually die because it's no longer receiving fluids from below. The mimosa will, of course, want to resprout repeatedly below the cut. As soon as any new growth appears, prune it off immediately; this will take continual vigilence on your part throughout the growing seasons. Eventually even the base of the tree will starve and die — although that can take years to happen.
Note: Before you decide to do any of these methods, however, make sure that as the tree dies and dries out, it poses no hazard to life or property if parts of it — dead limbs, or worse, the entire tree — fall. Is the tree likely to drop across property lines? On your house? Could a person or pet be injured? If you're comfortable that it presents no danger, then the dead tree could serve as a home for wildlife.
Tackling Trick Tree Issues
