I thought I'd planted a dahlia where this huge plant started to grow. It has a very thick hollow stalk and is now 6 feet tall. I finally realized it's just a weed. But what weed? Thanks in advance to anyone who knows....
Here are additional pictures. Help!
Could it be a delphinium? The leaves look similar and they produce a long hollow stalk.
The leaf reminds me of wild lettuce or a bur plant of some sort. What is the infloresence at the tip? Maybe when it opens or blooms, you can better tell what it is. Pondy
giant ragweed---see link
Here is a link that might be useful: giant ragweed pics
It was indeed giant ragweed--I got it out just before it seeded.