Sumac invasion!

Asked June 17, 2019, 12:23 PM EDT

I'm in Bend Oregon. I have found some 35 sumac suckers growing within 20 feet from a tree and another large sucker. They are growing up in the grass area. My research has shown that an herbicide for sumac works well but I'm hesitant to buy a gallon of the oil based herbicide. Mowing is said to encourage sucker growth. So what can I do? Go after the roots? Take a rototiller to the soil?
I am planning on regrading and seeding the area soon.

Deschutes County Oregon forestry weed issues sumac

2 Responses

Hello, unfortunately this is the growth habit of a sumac. Rototilling is likely to create and even bigger problem as many of the pieces may become new plants. I'm not sure what herbicide you found in your research but one that is registered for tree and sucker removal is Crossbow. It is a combination of 2,4-D and triclopyr. You may want to look into this and see if it will do what you are looking for. It is available in smaller quantities than a gallon. It is registered for non-cropland uses but you may want to check with NPIC at http://npic.orst.edu to be sure that this is a legal use (home turf) area for crossbow.

Yes, triclopyr4 is what I've found that says it works well on sumac. This a thorough site but it isn't local. I don't know if that matters for sumac.
http://pleasantvalleyconservancy.org/sumac.html

"Basal bark treatment of uncut stems


In high quality natural areas, where good populations of native species are present, the preferred method of basal bark treatment is with a hand-operated spray bottle. Sumac stems are fairly supple and can be easily pulled away from their bases. This exposes the base of the stem, uncovering a zone where other native plants are not present. One or two spritzes of herbicide in this stem region are all that are necessary to bring about the death of that stem. The herbicide to use is Garlon 4 (15-20%) dissolved in oil. (See photos below)

All stems in the clone should be treated.

This procedure is very effective, and if sumac is present as individual plants or small groups, a single treatment should be sufficient. For large clones, root suckers will form, either the same year or the next, and must be dealt with by herbicide."