Killing Tree of Heaven


#1

I wasn’t sure where to put this topic. Maybe we should have a special sub-category for dealing with invasive plants in our orchards, gardens, & backyards.

Some friends of mine found the Tree of Heaven growing in their backyard. They are trying to kill all of them that they can identify.

I have read Penn State’s fact sheet and they list several herbicides for use.
https://plantscience.psu.edu/research/projects/vegetative-management/publications/roadside-vegetative-mangement-factsheets/3ailanthus-on-roadsides

I think my friends said they have been using Tordon on stumps, or girdling and then applying Tordon. Looks like hack and squirt or injections may be more effective than complete girdling.

What is the best herbicide for foliar treatment of the suckers that pop up all over?

I found through a search here that many of you out East have been eradicating this invasive tree from your properties, in conjunction with controlling spotted lantern fly.

Care to share your techniques and products you have found to be most effective?
Thanks!!


#2

Hack and squirt with 40% glyphosate mid August to late September for anything bigger than 4" diameter. 4% foliar solution on suckers any time.

Might take more than one year for large trees.


#3

Thank you @hoosierbanana !
So a 4% glyphosate solution will kill back the suckers? I didn’t think that was effective against woody types, just grass and forbs.


#4

If you can keep the area mowed for a year or so in a drier climate, it will eventually be the end of them…and it helps if you can get the bigger portions of the stumps and roots. I managed that without any spray, but then we tend to be very dry.


#5

I’ve been spraying a lot of suckers here with 4-5% glyphosate. Looks like they are mostly dead now. Took three spays about a week apart to make them brown and crispy. Time will tell if they come back or not.


#6

My math may be way off… The 41% Glyphosate concentrate I bought suggests 6oz per gallon. I initially mis-read the instructions and used 2oz per gallon. And it killed basically everything I sprayed it on. At the 2oz per gallon rate would that not be about .6%? Making 6oz per gallon be 1.8%? Thanks.


#7

It depends on the plant. It doesn’t work on poison ivy and some trees, other trees are really sensitive though. It did work for me on toh suckers.


#8

The percentages are for mixing individual formulations. You are right that the actual concentration is lower. 5% solution of 41% is 6.5 oz. per gallon.


#9

Thanks, was pretty sure I still knew how to use a calculator :slight_smile:

Triclopyr > Glyphosate for this perhaps? It’s more geared to “woody” type plants and is effective on poison ivy.


#10

Ive been using roundup for 10 years to kill poison ivy. It takes about 2 weeks.


#11

Thank you all for your replies. I will pass this info on to my friends, I am sure it will be a big help. I know they are going to fight suckers from a vacant lot next to theirs. There are some mature TofH over there, and nothing is being done to control them.
Interesting responses to glyphosate too. It doesn’t kill poison ivy or bind weed here, at least not in a one-time application, but it will definitely damage fruit trees if you’re not careful! :face_with_raised_eyebrow:.


#12

Crossbow is my favorite ‘over the counter’ brush killer. Definitely does a number on poison ivy.
Doesn’t just melt the leaves and they come back like Roundup.


#13

Yep… Crossbow is Triclopyr + 2,4-d so pretty devastating on most any broadleaf plant…


#14

That sounds like the same active ingredients as Tordon stump killer. That’s what we use for brush and trees here. Works really well on honey locust.


#15

Tordon/Pathway are picloram + 2,4-D. Kills things well - but, I’ve had bad experiences with desirable trees near (within 10 ft) of trees that I did stump treatments on, being damaged… not killed, but it certainly made 'em really sick for a year or two.
Anymore, I won’t use that herbicide if I think the stump to be treated might share rootzone soil with a desirable tree… but ToH might be one that I’d use it on, even in that setting, if all else failed.


#16

Certainly does sound like Picloram could cause some collateral damage:

“Picloram kills or damages annual and perennial broadleaf herbs
and woody plants. It acts as an “auxin mimic” or synthetic
growth hormone that causes uncontrolled and disorganized
growth in susceptible plants. Picloram does not bind strongly
with soil particles and is not degraded rapidly in the
environment, allowing it to be highly mobile and persistent
(half-life of picloram in soils can range from one month to
several years). In soils, picloram is degraded primarily by
microbial metabolism, but it can be degraded by sunlight when
directly exposed in water or on the surface of plants or soil.
Picloram can move off-site through surface or subsurface
runoff and has been found in the groundwater of 11 states.
Picloram may also “leak” out of the roots of treated plants, and
be taken up by nearby, desirable species.”


#17

I’ve read that root-to-root contact between the sprayed Tree of Heaven and nearby trees, and that is what causes the unintended damage. Could be. I know ToH roots go many tens of feet out from the tree, especially in response to injury - just follow the new sprouts along the lateral roots.


#18

I had a toh in my yard send roots about 70ft., through the dirt basement, and popped up a sucker out of the far wall.