This has been an interesting learning experience. As I mentioned I’m not a fan of pesticides so this has been an opportunity to become familiar with them.
With most of the plants not showing much of a sign that they even noticed (wild roses do have a bit of wilting at the tips, dandelions and fireweed didn’t like it), I figure I would switch chemicals. Lesson number one: ignore the label, find the active ingredient, go home and learn about it.
The product I was using has glyphosate, and was labeled to kill weeds and grass. It is a non-selective, very broad spectrum herbicide; if it is a plant chances are it can kill it. It also has the lowest half life of household herbicides at 1~3 days, with replanting recommended to wait 7 days. On the other hand it can take a week+ for its effect to show, and several weeks with repeated applications before the deed is done. But because of the very broad/non selective nature and its tiny half-life, properly used this seems the ideal choice.
I picked a product called “Brush killer Plus; Kills tough brush roots and all. Plus kills stumps!”. You would think "Brush Killer Plus, that ought to kill more than the one labeled for grass and weeds? Nope. This has Triclopyr Trimethylamine, which is weaker than glyphosate, and it lingers around for waaaaaay longer. On one hand, on what it works on should work faster, but glyphosate can kill more things. Also while slower, it can rack a higher body count even at the slower pace. The bigger issue is the 30-day half life in the soil… As a general rule I see half life and multiply by 3 to find the margin of safety. It should be safe-ish enough at 2 months if you are not planting crops, but I would rather not lay down something that doesn’t like to break down in a hurry.
I’m returning the one I bought and sticking with glyphosate. These are plants with extensive root systems and showing to be resistant to herbicides, so I’ll reapply after a week and then every two weeks for a total of 4 applications. The main goal is to kill their root system. From there I plan on maintaining by hand.
One thing I need to do is to cover the tree trunks while applying and to cut down the sprouts coming from the ground so the trees don’t get a significant amount.
Glyphosate works best on perennials and shrubs when sprayed in late summer or fall, when the plants are actively transferring sugars to the roots. At that time, multiple applications may not be necessary.
Triclopyr when mixed with diesel oil will kill everything. In my experience, it’s more potent than glyphosate. You have to be very careful not to spray the bark of trees you want to save because it will penetrate the bark.
This is very true, and part of the reason why for many people it’s probably best to just do multiple applications of glyphosate. Even if you do screw up, you probably won’t kill a shrub or tree you’re trying to keep, just severely damage it.
Glyphosate can kill a full size tree but it might take a year. There are some plants that are resistant such as nutsedge, horsetail, and morningglories.
I have injected straight glyphosate into red cedars using a large syringe after drilling an angled hole with a battery drill. The cedars are still alive years later.
Gly doesn’t kill poison ivy, common ragweed, white clover, alfalfa, marestail, waterhemp, pigweed and some others here, even when spot sprayed at 4 oz. Gly/ 4oz. liquid AMS, and 1/2 oz. surfactant per gallon of water. I’ve repeatedly hit wild red radpberry and blackberry with gly overspray on edges of my foodplots at 2 qts gly/2qts liquid AMS, and 1 pint surfactant per acre. It sets them back for a few weeks, but they always come back.
I’ll stick to using Crossbow and diesel fuel applied basally in the winter to kill woody stuff growing where I don’t want it growing. IMO of course.
Don’t know about cedars but it certainly kills large sassafras and oak trees. It also has been killing poison ivy for me for years.
Good to know Crossbow and diesel works well. I’d be concerned about diesel in the soil.
You must have different oaks and poison ivy than I do. Neither species here will be killed by gly. Damaged, yes. Dead, no.
The areas where I’ve eliminated glossy and european buckthorn and American hop hornbeam with Crossbow and diesel are now thick jungles of aspen, various dogwoods, burr oaks, seviceberries, and other natives. I’ve got no worries about diesel or Crossbow in the soil. I suppose if I lived on a suburban lot with a few acres maybe I’d do something else. I don’t, so I don’t.
FWIW…there are other ( more expensive) additives you can use instead of diesel if that’s a concern. I imagine that’s what USFWS and other entities use when dealing with woody invasives.
Triclopyr is used in lots of products. Some, like Garlon 4 Ultra, describe using diesel in the label. Some others may not.
The concentration depends on the use. As a general herbicide, a 1 to 20 ratio should work. If you want to kill woody plants by spraying the bark (e.g. in winter), a higher concentration is recommended, such as 1 to 5.
My use of triclopyr has been limited to basal bark treatments in winter. But I know that utility companies in my area use triclopyr in diesel as an herbicide to clear utility right of ways, and it kills everything.
As I mentioned earlier, if you want to kill underbrush and preserve mature trees, you need to be very careful with triclopyr. Glyphosate is safer because it is less toxic if some gets sprayed on the bark or roots of desirable trees. Usually, glyphosate needs to be sprayed on green leaves to kill vegetation. But some plants are resistant to glyphosate. And if you’re having that problem, triclopyr is an alternative.
Crossbow will leave the grass unharmed if you want it that way. It plays hell on Canadian thistles. It only kills broadleaves. Not grasses. I did find out that it doesnt kill milkweed, and realeases them from thistle colonies. I’d test it first, but it cleaned up my grandkids Monarch butterfly patch.
Glyphosate will kill most things including grass. As Tomj said, brushy stuff you spray in late summer and fall. Its usually dead in the spring. Things like blackberries and rose. Its a rate thing, how much can you get into the plant…so multiple applications will help a lot on woody plants. A lot of people use it and think it doesnt work because its still green a week later.
I would spray cover crops with it in December and by March it would be dead. Same for fall annual weeds. Slow process due to slow growth.
I cleared an area last summer, and sprayed it 2 qts to the acre with AMS and a good surfactant and it killed everything. Grapes, poison ivy, grass, and any suckers. Sprayed it in October.
You can treat stumps with Tordon RTU. RTU means ready to use. Its Triclopyr in a bottle with blue dye. Nozzle has 3 holes and you just paint the top of the cut stumps. I use it on wild grape whenever I cut them. Also big poison ivy vines. I also paint the ash stumps so they dont sucker back and have to be cut down in a few years due to ash borer. Real easy to use and user friendly. It can be purchase at your farm store.
Don’t know how the town did this. They sprayed to kill poison ivy June 24 but it didn’t kill other plants. They did a large area and everywhere the poison ivy was dead but other plants were surviving.
Manual methods are mostly used on woody invasive plants when they are small. Eradication is only possible when the root crown or roots that can sprout are completely extracted and seedlings are pulled or eliminated following seed germination. Because it is
difficult and even impossible to extract all of the shallow roots, stolons, and rhizomes of many invasives, resprouting will usually occur.
Merely pulling small plants and cutting top growth will result only in short-term control before stump or root sprouting occurs, unless a herbicide is applied to cut surfaces.
But hand pulling will disturb the soil, creating a seedbed for other surrounding invasive plants that might be establishing in the site
If not planned and enacted with care, mechanical root raking and disking can intensify and spread infestations of invasive plants that have runners by chopping the runners into resprouting segments. All mechanical equipment used in treating invasive plant infestation can transport seeds, roots, rhizomes, and spores to other sites.
Land clearing methods have also been used in large restoration projects when infestations are extensive and dense, followed by herbicide applications to resprouts and seedlings followed by revegetation with desirable plants.
Herbicide applications offer the best means of containment or eradication, because herbicides can kill roots without baring soil—bared soil is susceptible to reinvasion and erosion. Decades of research has found that herbicides tested and registered with the U.S. Environmental Protection Agency (EPA) are safe to humans and other animals when stored, transported, and applied according to strict label directions.
These are official guidelines from the US Forestry Service.
