Invasive plants in Killing Off an Invasive Plant

By flaflwrgrl
November 30, 2012

If you have an especially invasive plant that is large and you want to get rid of it, you can cut it back to 3 or 4 feet. Drill holes 2 or 3 inches straight down into the cut stems, then pour Roundup into the holes. The plant will take the poison internally and it will kill any suckers as well. You may wish to refill the holes after about 12 hours. Please be sure to cover each filled stem with tin foil secured with a twist tie, so our lizard and insect friends don't get into the poison. I had a Shooting Star Clerodendrum that I had to treat this way. It was sending suckers out 30 feet away!

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valleylynn

Nov 29, 2012 7:19 PM CST

Thread OP

Name: Lynn
Oregon City, OR (Zone 8b)

Ann, I love this idea. We have an old seedling cherry tree we cut down and it just keeps coming back from suckers that come up from the ground. This will be what we do next.

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| @valleylynn | Post #331995 (1)

Last edited by valleylynn Nov 29, 2012 7:21 PM

Dutchlady1

Nov 29, 2012 7:20 PM CST

Great idea but I am not taking credit for it, Lynn!!

| @Dutchlady1 | Post #331997 (2)

valleylynn

Nov 29, 2012 7:22 PM CST

Thread OP

Name: Lynn
Oregon City, OR (Zone 8b)

Thank you Hetty. I corrected my above statement. I just saw photo by Dutchlady and didn't see the rest.

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| @valleylynn | Post #332000 (3)

Dutchlady1

Nov 29, 2012 7:43 PM CST

I hadn't even noticed it was my picture!

| @Dutchlady1 | Post #332007 (4)

flaflwrgrl

Nov 29, 2012 8:13 PM CST

Name: Ann ~Heat zn 9, Sunset
North Fl. (Zone 8b)

Dutchlady1 said:I hadn't even noticed it was my picture!

I am a strong believer in the simple fact is that what matters in this life is how we treat others. I think that's what living is all about. Not what I've done in my life but how I've treated others. ~~ Sharon Brown

| @flaflwrgrl | Post #332021 (5)

flaflwrgrl

Nov 29, 2012 8:18 PM CST

Name: Ann ~Heat zn 9, Sunset
North Fl. (Zone 8b)

I don't advocate the use of toxic chemicals but sometimes there is no choice when you have especially stubborn invasives. I came up with this method in order to try & lessen the impact to the environment as much as possible. It's certainly better than spraying the plant and it gets to the heart of the matter.

| @flaflwrgrl | Post #332023 (6)

mistyfog

Nov 29, 2012 9:43 PM CST

Name: shirlee
southeast (Zone 6b)

Ah, this is a good tip to know. Will use it too. Thanks for posting it.

| @mistyfog | Post #332055 (7)

valleylynn

Nov 29, 2012 9:56 PM CST

Thread OP

Name: Lynn
Oregon City, OR (Zone 8b)

If this works on that pesky tree, I'll be hugging you around the neck Ann.

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| @valleylynn | Post #332064 (8)

CarolineScott

Nov 30, 2012 6:42 AM CST

Name: Caroline Scott
Calgary (Zone 4a)

I will try this on some of the tree suckers that are growing over the flowers!
Thanks for the idea.

| @CarolineScott | Post #332125 (9)

Ridesredmule

Nov 30, 2012 8:47 AM CST

Name: Charleen
Alford, Florida (Zone 8a)
Walk in Peace / I'm Timber's Mom.

Wonderful idea. Thanks for letting us know....

Brugmansia *****Carnivorous Plants **********Charley's Girls

Posin Mule

| @Ridesredmule | Post #332151 (10)

Paul2032

Nov 30, 2012 9:13 AM CST

Name: Paul
Utah (Zone 5b)
Grandchildren are my greatest joy.

For woody plants the thing that works best is making downward chops or cuts through the bark with a hatchet and pouring in some full strength Round-Up or Brush Killer. This puts the killer in the Cambium Layer which is just under the bark and is where nutrition, etc moves down to the roots to kill the plant. The interior wood doesn't transfer it. There are pesky trees here such as Quaking Aspen and Poplar that sucker badly if you don't kill them this way before removing. If you just cut them down the roots put up countless new plants.

Paul Smith Pleasant Grove, Utah

| @Paul2032 | Post #332152 (11)

fiwit

Nov 30, 2012 3:24 PM CST

Name: Mary
My little patch of paradise (Zone 7b)
Gardening dilettante, that's me!

If you don't mind trying an alternative first, try using white vinegar instead of round-up. It might not be strong enough, but then again it might be. In a worst case scenario, it slows down the destruction while you wait to see if the vinegar works before trying a more toxic chemical.

Just a thought...

Northwest Georgia Daylily Society
I'm going to retire and live off of my savings. Not sure what I'll do that second week.
My yard marches to the beat of a bohemian drummer...

| @fiwit | Post #332224 (12)

valleylynn

Nov 30, 2012 3:51 PM CST

Thread OP

Name: Lynn
Oregon City, OR (Zone 8b)

Mary, I tried the white vinegar on a number of plants. It only worked on the more delicate types of weeds. Didn't do anything for Japanese Knotweed or shrub/tree type plants.

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| @valleylynn | Post #332228 (13)

fiwit

Nov 30, 2012 5:16 PM CST

Name: Mary
My little patch of paradise (Zone 7b)
Gardening dilettante, that's me!

valleylynn said:Mary, I tried the white vinegar on a number of plants. It only worked on the more delicate types of weeds. Didn't do anything for Japanese Knotweed or shrub/tree type plants.

Did you try it inside, like what Ann is recommending here, or just spraying it on the outside?

caveat: I've not tried it yet, but someone recommended I drill a hole and pour in white vinegar to kill a tree I didn't want. It's been on my list of things to do.

Northwest Georgia Daylily Society
I'm going to retire and live off of my savings. Not sure what I'll do that second week.
My yard marches to the beat of a bohemian drummer...

| @fiwit | Post #332244 (14)

Last edited by fiwit Nov 30, 2012 5:17 PM

Paul2032

Nov 30, 2012 5:27 PM CST

Name: Paul
Utah (Zone 5b)
Grandchildren are my greatest joy.

The interior wood of a tree is inert so drilling into it doesn't accomplish anything. The living active part is just under the bark so anything that is tried to kill the tree should go just under the bark.

Paul Smith Pleasant Grove, Utah

| @Paul2032 | Post #332251 (15)

valleylynn

Nov 30, 2012 6:37 PM CST

Thread OP

Name: Lynn
Oregon City, OR (Zone 8b)

I tried both ways with the Japanese Knotweed, drenching the outside parts (leaves & stems) and cutting some back and pouring the vinegar down the hollow insides.

Paul, thank you for the insight on doing trees. I will do what you suggested. Is it to late to do now. We still have some of the leaves on the tree.

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| @valleylynn | Post #332274 (16)

fiwit

Nov 30, 2012 6:48 PM CST

Name: Mary
My little patch of paradise (Zone 7b)
Gardening dilettante, that's me!

Thanks, Lynn!

Northwest Georgia Daylily Society
I'm going to retire and live off of my savings. Not sure what I'll do that second week.
My yard marches to the beat of a bohemian drummer...

| @fiwit | Post #332279 (17)

valleylynn

Nov 30, 2012 7:11 PM CST

Thread OP

Name: Lynn
Oregon City, OR (Zone 8b)

But there may be many plants it will work on Mary. I think the Knotweed is very difficult to get rid of.

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| @valleylynn | Post #332285 (18)

fiwit

Nov 30, 2012 7:18 PM CST

Name: Mary
My little patch of paradise (Zone 7b)
Gardening dilettante, that's me!

Mine's a bradford pear -- cut it down, ground the stump, and it's constantly putting up shoots from its roots. So when I get around to it, I'm going to listen to Paul and slice the skin instead of drilling holes, and try undiluted vinegar first.

Northwest Georgia Daylily Society
I'm going to retire and live off of my savings. Not sure what I'll do that second week.
My yard marches to the beat of a bohemian drummer...

| @fiwit | Post #332288 (19)

valleylynn

Nov 30, 2012 7:31 PM CST

Thread OP

Name: Lynn
Oregon City, OR (Zone 8b)

Hope it works. Our ornamental plum has been aweful. And it has thorns.

Sempervivum for Sale
Sempervivum ~ Sedum ~ Containers

| @valleylynn | Post #332293 (20)

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