What is this tall, broad-leaved plant from Central NY?

Question

I have this growing on the bank behind my cottage and am very curious to know what it is:

• It has long, broad leaves that narrow and expand drastically
• It's at least 6 feet tall
• The stem is about 1" in diameter thick, is green with purple streaks, and appears to be smooth.
• There are no flowers on top (this is in early August in the Finger Lakes region of Upstate New York)

Answer 1

It might be Lactuca biennis, commonly known as Tall Blue Lettuce, but without a close up of a leaf, and without knowing if it has short hairs along the veins on the underside (midrib particularly), and in the absence of any flower heads or actual flowers, its hard to be sure. Info here

https://www.minnesotawildflowers.info/flower/tall-blue-lettuce

Answer 2

In Iowa I am told it is called the California Thistle, and it WILL go to seed in the fall, in spades! It can infest a garden in one season!!

The only way I have found to successfully kill them is to cut them off near the ground and soak the stump with Round-Up. Hitting the leaves will kill this years plant, but it will still go to seed, and the root will survive!

Oh, they have spines on the stems, and they get stiff n nasty in the fall.

Answer 3

It looks like giant lettuce. You probably want to remove it before it flowers and sets seed.