There’s no nice way to say this so let me just be blunt about killing weeds. Some plants just don’t belong in your garden. Oh, you can name the reason yourself if you think about it:
- some are noxious weeds that bite back when you get to close.
- some are too aggressive,
- some don’t grow well enough to give garden space
- a few never flower even though the catalog said they’d flower all summer long.
- And, the thing they all share is that they are hard to get rid of or create a problem for you when you try.
So, here’s a handy summary of all the ways you can kill plants. You’ll notice that I’m not recommending you run out and buy a small nuclear device or heavy-duty spray to kill plants. You can, with a bit of patience and gardening savvy – eliminate most of the main problems you’ll see without resorting to chemicals.
The most obvious way is to dig the plant up.
This is pretty simple with most plants but there is a situation where the plant fights back. When a plant can produce a new baby plant from a section of root, then it will do so as long as there is a small section of root left in the ground.
This is why we see poplar or willow trees throwing shoots forever after the main trunk has been cut down. Invasive grasses do the same thing and they can be almost impossible to eradicate. Notice I said “almost” impossible. No plant – and I do mean no plant – can withstand the constant and repeated cutting off of new shoots and digging up of roots if it is done regularly and consistently. From dandelions to poplar trees, if you cut off the leaves and new shoots, the plant slowly weakens. Sooner or later it will die.
Now, nobody said it was as fast as poisoning the ground with a chemical to kill the plant. Nobody said it was less physical labor. I worked on some horsetail in my rock garden for about 4 years, and I got it down to a dull roar compared to its beginnings. The interesting part of this is that there isn’t a chemical that will work on horsetail and allow rock garden plants to live so weeding is the only solution. So, you can wail and moan and curse the gardener who allowed the plant to become established but the bottom line is that digging is the single most effective way we have to eliminate unwanted plants.
Covering The Plant
How about covering the plant with something else? I know a lot of gardeners who pile on the organic mulch. Every time they see a weed, they simply add another layer of mulch to cover it up and smother it down. This works too.
Newspaper or Cardboard
Even a full and healthy lawn of grass will be killed if you spread enough layers of newspaper and then cover that with an organic mulch such as leaves, straw or wood chips (to hold the paper down).
Note that using layers of newspaper or cardboard under mulch – as a weed barrier – is not recommended in an actively growing garden. Cardboard prevents water penetration and oxygen exchange in the soil – both of which will lead to plant weakening. Great if you want to kill everything but not so great if you want to keep plants alive.
I’ve written before about clear plastic sterilizing the soil if left there for a summer and this is an excellent way to eliminate unwanted plants. Cook ‘em under plastic.
Cover the area with clear plastic, dig the edges of the plastic under so no air can get in and sit back and let the sun cook your plants. It will take about 6-8 weeks and everything will be dead under there.
Stumps can be chipped down to nothing if you rent a stump-chipper from your local rent-all. That’s the fast way.
The slow way is to drill holes in the stump with the largest drill bit you have and fill those holes with wet garden soil or fresh manure; although I note that compost is almost as good.
The bacteria in the soil or manure will start to work to rot down the stump and the more holes you drill, the faster it will work.
You can purchase special stump rot preparations if you want to be sure of having a quick rot, unsprayed garden soil will have all the bacteria and fungi you need.
Mind you, if you’ve sprayed your garden soil to kill pests or garden problems, the fungi and bacteria you need may not live there anymore.
Noxious Plants Such As Poison Ivey
The big problem always comes with the noxious plants. How do you get rid of poison ivy for example? This is a tough one. It is still a plant and it still follows the rules of growing. You can eliminate small quantities of it by smothering or digging.
Having said that, if you contact the oil from the plant in any way – from actual skin contact to standing downwind of the smoke from burning it – you’ll regret it in a big way.
A week in the hospital when I was a kid taught me to watch for those famous three leaves.
If poison ivy or poison oak has managed to severely invade the property then this is the only time I’d recommend using a specific chemical for control.
Frankly, this is what weed control experts are paid to do. And I’d call one myself. (And I’m registered in the Province of Ontario to spray agricultural chemicals. This is a relic from my nursery days and I take the mandatory update every few years just to “force myself” to take the time to update my understanding of current legislation and products being sold.
My best advice if you have noxious weeds such as poison ivy and what I’d do if we had it on our property (yes, even though I’m registered) is to call a professional in your area.
Don’t bother spraying poison ivy yourself because they are usually so large that a single spray will not kill them or even slow them down. Spray drift will kill other plants in the vicinity. Cutting and painting will do the trick and this is a registered use of the concentrate. Do not get the chemical on your skin as you will absorb it as well.
How To Kill Woody Plants
For those of you where purchasing chemicals is still possible.
The risk to health outweighs the risk of using a chemical control; particularly when used according to these directions.
Note it’s critical for you to wear rubber gloves and ensure you don’t get this on your hands.
- Obtain some glyphosate (Roundup) concentrate – not the ready to use spray.
- Cut the vine of the poison ivy or stem if it is a small bush (wear protective clothes and gloves)
- Using a paint brush – paint the concentrate onto the woody stem of the plant.
- This will be absorbed by the plant and kill off the roots. The wound must be fresh and if you have to repeat the treatment, a new cut will have to be made so the plant will absorb the chemical.
If you can’t obtain the concentrate, call a weed removal specialist in your area
It’s never easy to say goodbye to a plant but that’s how you do it.