aha. Could that be a nyjer plant? just googled images of it and it looks mighty similar, and grows very tall. Popular bird seed for goldfinches.
I think you're right gg. I've never seen it, I had to google as well.
Ginglygangly I think you are spot on! Thank you! I looked it up and found several pictures that are identical to my monster. I had looked up niger plants before when I had another weed that looked similar (but turned out to be a bur marigold) but hadn't considered it for this giant, as it was said to be 30cm tall.
Searching under the name "nyjer" instead says it is 4ft on average but can reach 7ft. I think my monster enjoyed the vegetable patch and outdid itself! I am disappointed it never got to produce seed though, after all the time it had.
Thank you! I am glad to finally have this mystery solved.
I agree, it's Guizotia abyssinica, a not-uncommon birdseed alien. It's unlikely to become a nuisance in the UK as it probably won't produce seed here and as noted above, is killed by frost.
I'm quite chuffed with myself. I usually haven't got a clue about weeds!
You should be chuffed gg. This one's been running for ages with no answer.
Why don't I get these? there's plenty of seed spread about