How can I control thistle in a lawn?

Question

Our back fence (an iron bar fence) borders a golf course, and between us and the fairway is about 50 feet of "native" landscaping. This mostly means long, native grass (some type of crab grass?).

Unfortunately, next to one section of my backyard, a large patch of thistle grew up very tall a few years ago. While thistle can turn out very pretty...

^{image source}

... it's also terrible when even small growth appears in my lawn. Given how spiky it is, bare feet is not a good idea.

I ended up spraying weed-killer on this patch and got it mostly knocked down. However, the bits that had already spread to my lawn have come back year after year. They don't go away when I spray with lawn-safe weed killer, and I even had Tru-Green service for a while and nothing they did was successful either.

I have tried pulling them out by hand, but our lawn, unique soil (solid clay), and the toughness of the root system makes most of them simply break off at the soil, leaving them to come back in just a few weeks.

Is there anything I haven't tried? Or should I just keep trying to dig them out by hand?

Note: since I've been more attentive to the patch on the other side of my fence, and it hasn't gone to seed in a couple years, the weeds have stayed confined to about 200 sq. feet of my lawn.

Lawn type: Kentucky Bluegrass
Climate: Semi-arid (grass growing season is about March/April to October/November)

Answer 1

This link covers various ways to attack thistle infestations. I do believe your approach is probably the best.

I would continue to control the spread of the plants on the other side of the fence and try to pull them out as long it does not create unbearable labour.

I can also offer a few suggestions for thistle:

• If possible, loosen the ground around the base without breaking the roots before you pull it
• The best place to grab the weed is just below ground level when you pull them up

Personally, I do not like chemicals and would consider them a last resort. Do everything necessary to get the ENTIRE root!

Prevent the spread of seeds, get the root

Answer 2

I've got the same problem, where there are fields of dandelions just beyond the borders of my gardens. I've also had the same problem, where chemicals would kill the weed off, but couldn't prevent it from returning. Plus, with keeping pets, I don't like to put down biocides where they might ingest them (stupid cats and their grass-eating).

Instead, I get better results pulling the weeds from my lawn physically. I use this weed pulling tool to improve my chances of getting the root instead of just the leaves. I don't have any affiliation with the company - I'm just happy to find a tool that has made getting rid of weeds less of a chore (and actually kinda fun now). You won't get the root every time, but I've pulled out some monster weeds with it (12" long roots).

If you've got regular problems with weeds in your lawn, it's probably a good idea to invest in a similar tool, just to make the job easier. If it's anything like my garden, you'll have to do it regularly to keep on top of the problem.

Answer 3

My yard when I bought the house a had a thistle problem. Started as a few at the corner of the lot, and eventually started to sprout up in a line down the yard (like a tank column). Some were >1ft in diameter.

I eventually killed them off with a lawn weed spray (Ortho Weed-Be-Gon or Spectracide, whatever was cheaper at the time). For the bigger ones, it took weeks for them to die. I also had to re-spray a few times. Make sure you spray the center of the plant to kill the root! Eventually, they shriveled up and vanished. I was left with some bare spots in the yard I had to re-seed.

It was 2 summers before I really had them under control. I occasionally find 1 or 2 small ones in my yard while mowing. I make it a point to spray them as soon as I find them.

Answer 4

When I was actively going after the thistles in the lawn, I used vinegar right down the center of the plant. Killed the growth, controlled the spread effectively and didn't hurt our animals. For several years, using this method, I have only seen a handful try to reemerge and were quickly tamped down.

Answer 5

I bought a foreclosure that had a front lawn made up of around 30% thistle, located in Columbus, Ohio. I used weed-b-gone that hooks up to the hose and repeated this about every three weeks all summer; about 5 applications. I hardly have any now. After overseeding in dormant winter, I am getting compliments on my lawn and how I pulled it off.

You can kill the thistle above ground, but the underground root will still survive and sprout multiple plants after that. Each time a weaker plant and using more of the stored energy. After several generations of losing to the weed killer, it dies. Good luck. It was actually very easy IMO.

Answer 6

Thistle is classified as a noxious weed in most places and must be controlled. Talk to the golf course and they will probably deal with what has not invaded your yard (you might even get them to take care of what has invaded your yard, depending on who owns the course).

If they fail to deal with the problem, you can report them to your local ordnance control.