Emily, I don't know that anyone here can add anything to calm your concern. The label instructions say not to spray undergrowth within the drip line of desirable trees, in fact it states to stay outside by distance of twice the number of feet in the drip line. The problem with this product for home use is that its rated 'highly mobile' in soil. Rain, irrigation, any degree of slope will move it to areas you did not mean to treat. This product and others similar are rarely appropriate for residential landscapes. All you can do is wait and see what happens.

Ok, thank you for the reply. Cheers!

Emily, if you think of it later, maybe you could report back here and let us know your outcome. It might be helpful to others...

It's been about six weeks and the trees look fine. I am pretty sure if there was going to be ill affects it would have shown by now. For the record, everything that I intended to spray with RM43 is dead as can be, so I highly recommend that product for anyone with a long run of fence that they don't want to weed eat. I shan't be spraying it around trees in the future though.

Thanks for the help morz8! Take care!

Keep in mind that the World Health Organization has listed glyphosate products as potential carcinogens.

kimmq is kimmsr

How have your trees faired so far? I accidentally did the same thing around/under spruce trees.

They are good, I haven't seen any harmful effects : )

Hi Emily,

I wondered how your trees have fared since this post. I've recently sprayed a 1/4 concentration on some weeds around my favorite live oak and am now terrified I've killed my favorite tree!

Hey there brentwgraham. My trees are all fine, none of them even showed signs of stress. I doubt you have anything to worry about.

Any updates on your trees for 2018? My husband just did the same thing in our yard and I’m so afraid he may have caused irreversible damage to our beautiful trees and shrubs. Our home is completely surround by a large hedge with established and newly planted trees. I have been the yard person for 25 years and I’m infuriated that he may have wiped out all my hard work in a few hours!

Trees are all still alive and well, none of them ever showed any signs of stress or damage from the spray. The spray I used is extremely potent as well (RM-43). I think your trees will be just fine.

Emily... Thanks for your followup on this thread. Information badly needed.

Hello, RM43 (Glyphosate Portion) absorbs into the plant primarily thru the leaves. The Imazapyr (Pre-Emergent) tends to enter the weeds thru the leaves also, but also stays on the surface as well. Neither tend to soak into the soil or get deeply into it. Since most trees have deep roots they are not affected much by it. However, I would not spray it on tree leaves directly or very young trees that I wanted to keep. I use a light spray on the weeds leaves around my trees and have not seen any negative affect on my trees. (6 years of spraying yearly)

Gardengal i literally just read through that Forestry Service study 5 minutes ago before a new search brought me here. Thank you for the accurate informayion on imazapyr’s impsct on trees.

Yeah while this is bumped, I will say imazapyr can DEFINITELY kill trees through the roots. I use it on my 3 acres, very very sparingly, as a 'last resort' herbicide. Over 10 years ago I had a huge colony of poison ivy that had set seed the prior year, so I wanted to ensure I both killed the PI and stopped the seeds from germinating. There were 2 cherry saplings, about 2" caliper, in the area too. The cherry sapling closest to the PI died, even though I definitely did not directly spray its foliage. A sapling at least 1 meter away from the spray pattern still turned yellowish for the rest of the year, but did not die. It must have had roots running into the area of PI roots.

Well it worked like a charm, and it took about a year for anything to start growing back in that area. I had no PI seedlings the next year. I don't think it inhibits germinating seed per se, but kills them after they have germinated.

I also used it when I discovered, to my horror, a female tree of heaven. It had been shaded by a huge maple that I had cut down, and now could flower and had done so. A moron neighbor of mine has a male tree of heaven in his yard, so it was pollinated. After cutting it down I drilled 3 holes in the trunk and filled with imazapyr concentrate, to make sure it was so dead it couldn't produce runners. It did not, and anything within about 1 meter of the trunk died just from what was released by the root system! OT but it was interesting to hunt down and burn every last cluster of about-to-mature seeds and nearby stem tissue. They burned with a curious vigor...I've seen the same with rose of trailer trash sharon, as I call it. Another invasive that ought to be banned. Maybe something about the way seral plants from monsoon-climate China grow means they quickly produce light, open structured plant tissue that burns with exceptional speed? The other things that burn crazy vigorously are dried conifers, of course, and even more so, dried Mediterranean scrub! After Polar vortex winter 1, a GIGANTIC rosemary, about 6'X4'X3' and 3-4" caliper, completely died. (was Hill Hardy, which is in fact NOT the hardiest by a longshot, in spot of what nursery catalogs might say. The "Blue" series introduced by UGA is much hardier on the east coast at least, like 'Blue Spires'. Hill Hardy and Arp were selected in Texas, and are maybe hardier there.) Anyhow I burned that sucker later that spring and OMG...the flames for a couple seconds reached 10-15' high! Absolutely astonishingly!

I mixed about 1/3 of a 2.5 gallon into 16 gal broadcast sprayer and it got my 30 year old trees and new. I am now in the process of watering the hell out of them to hopefully diluting the overspray with water. I live in the high desert and have a LOT of sand unwanted weeds, tumbleweeds, russian olive trees and bushes (which I hate) that was the reason for such a hot mix my only hope is I can save my 30 year old trees.

Yvette - how is your 30 year old tree doing?