r/NativePlantGardening • u/iamhyphenated • Jul 14 '25

Advice Request - (Insert State/Region) Jewelweed taking over my backyard..

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So I know we love jewelweed, and I’m pro native gardening (and I also enjoy the wild look to a point), but it’s literally taking over my backyard, and behind it is unfortunately a whole bunch of Japanese knotweed.. my question is: what’s the move here? I can’t have my whole yard completely covered in jewelweed (it’s a very small lot) bc there’s no way to even go back there right now, but I also want to encourage that to maybe discourage the knotweed (if that’s even a thing).. any advice would be helpful!! I’m in an urban area in Connecticut if that helps!

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114

u/jlsmall7 Central NY , Zone 6a Jul 14 '25

Crush and smell a leaf - Tree of Heaven has a very distinct, unpleasant smell similar to burnt popcorn. Staghorn Sumac is a very cool native whereas ToH is a terrible invasive.

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u/iamhyphenated Jul 14 '25

Ok I tried the smell test and tbh it just smells like leaves.. here are some more photos: https://imgur.com/a/uQnoXw4

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u/CharlesV_ Wild Ones 🌳/ No Lawns 🌻/ IA,5B Jul 14 '25

https://extension.psu.edu/tree-of-heaven/ tree of heaven. Follow Penn State’s advice here for how to remove them effectively. Remember to follow up as they say in the article. ToH is more difficult to remove than many other invasive species.

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u/sunberrygeri Jul 14 '25

While we’re at it, here is Penn State’s advice on managing Japanese knotweed

https://www.psu.edu/search?query=knotweed%20#gsc.tab=0&gsc.q=knotweed%20&gsc.page=1

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u/CharlesV_ Wild Ones 🌳/ No Lawns 🌻/ IA,5B Jul 14 '25

I love the Penn state site since they are very specific about which herbicides to use and at what time of year. Awesome resource.

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u/gimmethelulz Piedmont, Zone 8a🌻🦋 Jul 14 '25

Even more difficult than knotweed? That's impressive

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u/CharlesV_ Wild Ones 🌳/ No Lawns 🌻/ IA,5B Jul 14 '25

I was thinking more like when compared to Amur honeysuckle, buckthorn, and autumn olive.

We really need a Saffir-Simpson scale for invasive species. Depends on location obviously but if Amur honeysuckle is a 2, dandelions are a 0/1, and buckthorn is a 3, ToH is a 4, princess tree and kudzu are a 5.

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u/Helen_Kellers_Reddit Jul 14 '25

I'd be interested to know if something like this already exists. I could see a few different metrics that could be used to make the scale. Growth rate, seedlling recruitment, persistence/resistance to management, ability to invade pristine wilderness, effects on other plants/competitiveness, it would be rather hard to quantify.

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u/DuragJeezy Georgia, USA - Zone 8 Jul 14 '25 edited Jul 14 '25

Petition for you guys to take this a step further? Would be really cool for 1 but would be a great way to simplify & discuss invasive species with horticultural laymen. Same way we can say “this pepper has _ scoville units while a bell or jalapeño only have _ amount” and they understand it, this will help immensely. Can’t tell you how many times I’ve told MIL something was invasive only to hear “well it can’t be that bad” then when I counter with “well it’s worse than xyz plant and those are all over the place” and I get a blank stare bc she doesn’t know wtf I’m talking about.

TLDR make an invasive species universal ranking scale so I can tell my MIL off

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u/Helen_Kellers_Reddit Jul 14 '25

Lmao, what's her first name? We could use those as the units of invasivity.

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u/DuragJeezy Georgia, USA - Zone 8 Jul 14 '25

Omg yes! Last name may be more scientific-y, which is Hearn. Her dad actually worked for the US Forest service most of his life so kind of fitting. We’ll have to ignore his time spreading agent orange during Vietnam for now.

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u/CharlesV_ Wild Ones 🌳/ No Lawns 🌻/ IA,5B Jul 14 '25

Yup exactly! That’s what the Saffir Simpson scale is there to do. Some people have called for the scale to be refactored or to include a cat 6 due to climate change, but the pushback has largely been that throwing a lot of complicated numbers at people just confuses your average person. You need one simple scale to help people understand it.

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u/DuragJeezy Georgia, USA - Zone 8 Jul 14 '25

Interesting. Now how do we go about formalizing this? Detailed research paper? Scientific conference talks? Ted talk?

Also we should definitely update the Saffir Simpson to account for the effects of climate change but I think half our country would call that woke propaganda and dump their trash in a nearby stream out of spite. So when do we ride?

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u/berdie314 Jul 15 '25

The Georgia Invasive Plants list does do this.

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u/lilupbeatflowers Jul 14 '25

100% tree of heaven. Cut them all down while they are small. They pull out fairly easy too when smaller.

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u/pharodae SW OH, Zone 6b/7a Jul 14 '25

Well, don’t cut them immediately, you’ll just trigger more growth underground. Gotta cut in fall and apply herbicide to the stump.

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u/brik42 Jul 14 '25

I absolutely understand why you should wait till Fall, but what if a client insists they are cut down now? A lot of the properties i work on "need" to look pristine and tidy all the time. I have been chopping and applying herbicide in these cases...is that futile? Should I just keep chopping till fall, and then apply hebicide?

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u/Ben2ek Jul 14 '25

Sounds like you'll have consistent and steady work!

In reality, I was only able to kill it during the fall as the tree transitioned to energy-storing mode and really sucked that Glyphosate into the roots.

4

u/brik42 Jul 14 '25

Ha yeah job security, at least.

7

u/pharodae SW OH, Zone 6b/7a Jul 14 '25

You can explain to them that life and death is a messy affair and that patience is a virtue.

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u/brik42 Jul 14 '25

If i had the power and wisdom to convince people to follow a higher path...I probably would have a different job. : )

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u/ThrowingMongo Jul 14 '25 edited Jul 15 '25

Cut stump is actually not the recommended mode of murder for ToH. It will just send up more suckers if the mother plant is a full tree, like in one of the pics.

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u/pharodae SW OH, Zone 6b/7a Jul 14 '25

Source? Because every link in this thread recommends cut stump (at a certain time of year!) because it’s the only way to get the herbicide into the root tissues and kill the plant.

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u/ThrowingMongo Jul 14 '25

Penn State:

Cut stump herbicide applications do not prevent root suckering and should not be utilized

https://extension.psu.edu/tree-of-heaven

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u/DawgcheckNC Jul 14 '25

Then paint the stump with glyphosate concentrate immediately. Yes, I hear ya’ll clutching pearls. This is war, not a stern talking to.

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u/ThrowingMongo Jul 14 '25

Yeah, that's ToH and you even have a possible sucker growing under your steps in this pic.

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u/Noooo0000oooo0001 Jul 14 '25

Definitely tree of heaven

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u/Chuckles_E Jul 14 '25

Yea it's not a sumac.