Cirsium arvense is also known as Canadian thistle, creeping thistle, or just thistle. Due to the root system that this perennial develops, it is very difficult to eradicate from your garden.
First off, NEVER NEVER NEVER let the thistle go to flower and seed. Why? Thistle will reseed all over your yard, and the seed is viable for 22 years- That’s A LONG time.
If there is thistle in your garden and you wish to keep all the plants where they are, your best bet is a cocktail of chemical and manual labor. I always cut any green growth off to soil level whenever I see it. This will eventually starve the roots of energy and food which the plant needs to survive and weakens the vigor in which the thistle rejuvenates. After cutting it down, instead of spraying the Round-up herbicide, I prefer to drip a few drops of it into the hollow stem which protects surrounding plants and seems to weaken the thistle more.
When the thistle issue is also creeping into your lawn, I’ll use a broad leaf product with 24-D, such as Weed-B-Gone, in these areas. Even if you completely remove the thistle from your garden, it will creep right back in via underground runners.
When dealing with a large area of thistle, my best method of control is to lay a thick layer of newspaper (6-8 sheets) and cover with a 3-4″ layer of organic material (woodchips, compost, grass clippings, or leaves). Perennials then may be planted directly through the newspaper/organic material layer. If any thistle pops up, I return to the cut down/Round-up dripping process.
When time isn’t an issue, I lay a heavy duty tarp over the entire area (plus another 3-4′ past where the thistle is growing). Then I cover the tarp with 3-4″ of organic matter. It’l will take about 3-4 years for the thistle roots to die off completely before the tarp can be removed and area planted.
Everyone will have this weed sooner or later. But once you get it, and you can get a lot of it. There are a few easy things you can do to keep it from taking over your property.
Most important is to never let it go to seed. Pull it, mow it, weed-wack it. Just don’t let it go to seed. If it does go to seed you will have hundreds-thousands-millions-billions of little baby garlic mustards growing. You can either hoe them, or spray them with any weed killer. More will return as the seed can live for up to 5 years. You can use a pre-emergent such as preen to control future infestations.
This is a plant that I see for sale EVERYWHERE! I always think that there needs to be a law created for people that sell these plants. Every time a plant like this is for sale it needs a huge warning on it. It should be posted…
“Warning this plant is known to cause constant diggin to remove, and will eventually take over your yard.”
Ok so don’t plant it in the ground? Maybe I can use it for containers? Wrong! This plant also will pop up from seed.
Once you have this plant it is VERY hard to remove. Traveling rapidly by underground runners all the way through your garden and other plants, you have to use a broad leaf weed killer on it. When trying to dig it out, ANY piece of root left in the soil will grow a new plant.
Plant can be mowed down to soil level, then once the plant is coming back spay with 24-D. Then wait 2 weeks and spay again. Next lay a carpet of newspaper down about 10 sheets thick. Then use a thick layer (3-5″) of wood chips. Wait a full year before planting any new plants in this area.
This beautifully variegated grass of white and green sure looks good at first. But if left unchecked will spread all the way across your garden into your neighbors and throughout the neighborhood. Ok maybe not that bad. If you must have it put it somewhere it will stay contained. If you wanna get rid of it, keep on diggin. You can have it gone in about 2-3 years, but stay on top of it, or it will creep back into your life.
A hardy beautiful tropical looking vine that attracts humming birds? Whats wrong with that? This gorgeous plant has a mind of its own and goes where it wants. At about 25′-30′ full size, roots close to your deck? Trouble! Close to your foundation? Trouble! I have seen suckers coming up 20′ from the mother plant! And if you want to get rid of one? Well gotta cut it down and either pull out or spray with chemicals any part that comes back. This can take YEARS! So if you must have one put it in the middle of nowhere so you can mow over any suckers that pop up. And remember you’ll have it forever! I do have 2 ‘Flava (a yellow one) and ‘Flamenco (A red one) on 4×4 post. If its still there… (The trumpet vine has completely covered any remains of that.)
Campanula or bell flower has awesome purple, or pink flowers. Sold practically everywhere that sells plants, this perennial will quickly fill a large space and most likely seed to other open spaces in your gardens and fill those too. Highly invasive and trouble some, spreads also by runners. These roots may go far as 3″, no wait 3′!!! into your soil.
Eradication is almost impossible as it creeps into the clumps of any other perennials in your garden beds. The best way to deal with this garden beast is to dig it out, or spray with round-up or weedbgone as soon as you see it ! If your neighbors have it, you will be dealing with this forever. Good news is that if you keep pulling it and spraying it with chemicals one day it might be manageable.
Stay away from this plant… This is sold almost everywhere, I dont know why… But it is. If you have unlimited space, and no other plants you care about – you can plant it. But it will be there forever!
To try and exterminate it… I try digging as much of it out as I can. What comes back I will then dig out, and if possible spray with round-up, or 24-D. Once the plant growing into another plant it is very difficult to remove. The best way to do this is dig out the plant, wash of all soil, then pull out every little root you can find of the bishops weed.