Weed/thistle ID

W Hartford, CT(Zone 5b)

Can anyone ID this? Last year I had a dozen of these, 6-10" diameter. Now I have 2 giants that have snuck up on me over the last 2 months. One is 3.5', this one is 4.5' diameter. I didn't seen any flowers last year. The thorns easily penetrate thick leather gloves. The roots are very deep and long. It seems to be invading nearby plants.

Thumbnail by birdmanct
W Hartford, CT(Zone 5b)

Older leaves

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W Hartford, CT(Zone 5b)

newest leaves

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W Hartford, CT(Zone 5b)

Roots

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Northern, IN

Good lookin pics!

Sorry I can't help on the ID.

An Asteraceae of some sort?

First year rosette of Carduus nutans? A Cirsium?

W Hartford, CT(Zone 5b)

Thanks dwdruley. That's about all I could say for sure :)

Equilibrium, I think you're probably right, but I spent 4 hours searching for photos of Cirsium arvense [Canada thistle] and C. vulgare [Bull Thistle] before I finally found one that almost matches. Here's a C. arvense. It doesn't really match.

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W Hartford, CT(Zone 5b)

Here's a C. vulgare [Bull Thistle]. It doesn't really match.

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W Hartford, CT(Zone 5b)

Here's a C. vulgare [Bull Thistle]. It's the closest match I've found. Since it's biennial, I wouldn't have seen flowers last year. Now, if that's really it, how do I get rid of ones that were 4 feet in diameter with tuberous spreading roots many feet long?

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Nice horribly long roots on all of those species. You are in CT... best to wait until next spring to get them. Don't panic, they'll be waiting for you when the temps warm up. Wait until your outdoor air temps are going to be in the 70's for about a week straight or your chemicals will not work. It would be my suggestion that you get yourself a nice small sponge and get yourself some regular strength RoundUp and pour a little into a tray. Wait until your little uglies are photosynthesizing their little hearts out around noon and start dabbing them with the chemical toward the center of the rosettes and outward along the leaves. Wait for 10 days and see how they are doing. You wouldn't want to apply too much chemical or it will kill off the top growth and strangulate it from traveling to the roots which is what you don't want to happen. Better to kill these slowly... besides which, I like to watch them die since they are so darn invasive! If the plant is looking like it is laughing at your attempts to kill it, sponge it again at the 10 day mark. Both Carduus and Cirsium are actually pretty easy to kill off with RoundUp but not too easy to kill off by digging up because of those roots.

W Hartford, CT(Zone 5b)

Thanks Equilibrium, great advice. I'll let you know if the UConn Extension Center says anything different.

Cool! New ways to beat these things back are always coming out! I sort of tire sitting on my fanny with a sponge so anything that works that might be less labor intensive to my rump is always appreciated. It isn't so much sitting on my fanny as much as having to scoot around on it dragging the tray along with me as I go from plant to plant to avoid having to get up and down and up and down. The reason why I use a sponge is to avoid overspray and drift. I want the chemical to go where I want it to go not where the wind wants it to go and there are just too many critters around here that could get into it. Best wishes to you, Lauren

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