Nice result with sumac

If you have been following my posts for the past two years, you have seen the progress we have made eradicating sumac using 20% Garlon 4 in oil as a basal bark treatment. Each sumac stem is pulled back to expose the base and a single spritz of herbicide (from a spray bottle) is applied at the bottom. This technique really confines the herbicide to a narrow zone around the stem, thus eliminating any problem with peripheral damage to "good" plants. With small patches or isolated plants (that would in a few years become large clones), complete eradication usually occurs with a single treatment.

On Saturday June 5 we used this technique at a Prairie Enthusiasts work party at Black Earth Rettenmund Prairie. The north unit, which had not been burned, had lots of medium sized sumac plants, scattered in small patches or as single plants. The photos here were taken today (8 days later) and show the results.

The herbicide causes the leaves to wilt within a few days, and after a week they have turned red. Within two weeks the leaves are black and then fall off. Because sumac is clonal, with an extensive underground network, it is necessary to treat every stem. With large clones, complete eradication may require a second treatment due to the root suckers that arise from still-living rhizomes. However, my follow-up studies with relatively small clones, or single plants that are well separated, showed that a single herbicide treatment is enough to eradicate.

If there is nothing much "good" in an area, then a backpack sprayer is quicker than a spray bottle, but I don't advise that in high-quality sites, as control of the herbicide is less certain.







Because the herbicide is confined only to a narrow band at the base of each stem, no peripheral damage occurs. At Black Earth Rettenmund, compass plant and lead plant were very near to treated plants and were not affected (the photo to the left shows lead plant and a dead sumac side-by-side).

The key to sumac control is to catch the clones when they are still small, and be sure to treat every living stem. Those stems missed in the initial treatment will be easy to find, as they will still be green while the treated plants are red and dead!