I have read the two previous posts regarding honey locust, but wanted to post a separate a question regarding killing honeylocust. I have a piece of property with an old, fallow cattle pasture that I'm turning back into timber. I'm planting various types of oaks and walnut seedlings in the pasture, but there's quite a bit of honeylocust already there. I've tried cutting down the trees, but sprouts just come back from where I cut the tree to the ground. I tried treating the foliage of many of the sprouts and young honeylocust with Glyphosate, but they appeared to shake off the treatment. From what I understand, I can apply a basal spray to the lower 12" of the stem and root collar. So my first question is can I apply the basal spray even in the dead of winter as long as the root collar is not covered with snow? I have read the OSU fact sheet regarding commonly used herbicides for basal sprays but was wondering there are any in particular that you would recommend? Where can I buy these herbicides beyond just searching for them on line? Are there any dies or markers that I can put in the spray to mark a tree once I've sprayed it? Thanks for you help. This website is a wonderful resource.

Greetings Jeff:

First of all, thanks for the kind words and I'm glad you're finding this forum useful -- we greatly appreciate the constructive feedback!

Based on some work by extension specialists at University of Arkansas, it appears they found Dow's Grazon P+D herbicide (Picloram + 2,4-D) to be very effective in treating honeylocust sprouts -- they used a 1% foliar solution, applied to both honeylocust and black locust seedlings.

Regarding basal applications, Triclopyr (ester formulation mixed with basal oil) is your best bet. Garlon 4, Garlon 4 Ultra, and Pathfinder II are two examples of triclopyr-ester products from Dow AgroSciences. Garlon 4, at 25-30%, mixed with basal oil and a colorant will do the trick. Pathfinder II, on the other hand, is a Ready to Use (RTU) version of Garlon 4 -- it comes pre-mixed as herbicide+basal oil, but Pathfinder II typically does not contain a colorant.

Some "forestry" basal oils contain an oil-soluble colorant; however, this varies by manufacturer. Basal oils and colorants are relatively inexpensive when compared to the cost of the herbicide. Examples of basal oil/colorants include Townsend's Ax-It & Trail Lite 2000.

Yes, you can apply Tricloypr-ester herbicides during the dormant season as basal bark treatments -- the oil-based herbicide and oil-based carrier -- penetrate the bark of trees < 6" in diameter.

Where to buy in Illinois? Local FS dealers; Rural King; and Farm & Fleet. Your FS dealers will likely have a much larger selection of forestry-, pasture-, and CRP-labeled herbicides. Don't be afraid to try some of the generics out there.

Hope this helps!

Hi...I found an older post regarding honeylocust, and I have a similar, yet different issue. I moved to a home where there are many honeylocusts, but one large tree had been cut down, and the stump was buried. This past spring/summer/fall, I have been fighting sprouts on a daily basis. The root structure seems very vibrant, and sends sprouts all over my large front yard. I've plucked the sprouts, but that's a stop gap.

Question. Should I remove the stump, or is there a way to "kill" the stump? I assume if you eliminate the source, the root system will die and cease sending shoots? If not, what do you recommend. If this would work, how would you suggest to best go about it... and in what season? Any information you can lend would be GREATLY appreciated as it's really affecting both my yard and the overall property value.

I would encourage you to use a broadleaf systemic herbicide to effectively "kill" the stump and root suckers from the parent root system.

Option #1: Cut all the honeylocust root suckers at the base and apply a small amount of systemic herbicide, such as Picloram (Pathway or Tordon RTU). Picloram only works on freshly cut stumps. In essence, you are introducing herbicide to the entire root system, thereby effectively killing the stump and all future root suckers. This can be done anytime of year, including winter!

Option #2: Unearth the stump, make a fresh chainsaw cut across the stump, and apply a systemic herbicide, such as Picloram (Pathway or Tordon RTU). In essence, you are introducing herbicide to the entire root system, thereby effectively killing the stump and all future root suckers. This can be done anytime of year, including winter!

***YOU ARE PERSONALLY RESPONSIBLE FOR THE APPLICATION OF HERBICIDE. THEREFORE, YOU MUST READ THE HERBICIDE LABEL AND FOLLOW ALL MANUFACTURER DIRECTIONS***

Option #3: Contact a certified arborist for on-site assistance.

In my instance, stump grinding was performed and grass seed was placed in Spring (last year). So there was no stump to apply herbicide. By the Fall (of last year), the locust tree shoots would come up all over my yard, like the plague. I’d get outliers 75 feet away, and across driveways and sidewalks! The reach of this root system was amazing. Like a warrior, I hand-picked what I could, and kept mowing the rest for the rest of the year.

This year, like a bad horror movie, they have returned with a vengeance. Clearly there is a lot of energy remaining in the root system. Obviously I am in need to help fight the locust invasion as I’m not getting younger, nor can my back take it much longer, but another question is will this continue into perpetuity, or is there an end in sight?

They are a plague and should definitely be considered an invasive species with a warning label to anyone who would consider planting one.. Good luck. We gave been mowing and battling over 5 years on one tree. The problem being we now have hundreds in our yard. Can't wait to move!!!

We had a honeylocust removed (with stump grinding) around one month ago. Now I am reading about the sprouts that will shoot up from this species....is it too late to apply a herbicide or other. the mulch is all over the tree still and next spring we were planning to lawn over the area. I wish the tree had stayed. It seems more trouble that when it was there.....other tips or suggestions. this is a moment where I wish i could turn back time and have kept the tree. A hasty decision to remove on our part.

I had a large locust taken down and all the trunks ground because of damage. I was not aware of the continuing issue from the sprouts until after I invested considerable in sod, water, fertilizer, etc. will any of the preventives work without damaging the new grass?

Helen, Using a broad-leaf specific herbicide, like the picloram referenced in the forum above, will work on the sprouts but not impact the sod. Keep in mind that picloram can move in the soil or through root grafts so is a threat to nearby trees if applied at a high rate. If you are unfamiliar with this type of work, I would recommend consulting with a certified arborist to make the application.