I'm guessing Jerusalem Artichoke. If that's actually what it is you can harvest the tubers. They are very good to eat.

Eric, thanks for your reply. The flowers and size certainly match but I think the leaves on my plant may be too narrow. They are quite narrow and have the folded look you see in the picture - maybe another kind of Helianthus? I will check and see if it has tubers.

Hmmm....I would guess either Jerusalem artichoke like Eric suggested, or maybe Maximilian sunflower(Helianthus masimiliani, a perennial type which I grew in my last garden. I'll put a link to a picture of a Maximilian sunflower below.

Let us know what you think, and/or if you get a positive ID.

Take care (and nice pic by the way),
Grant

Here is a link that might be useful: Pic of Maximilian sunflower

Grant, that's it - Maximilian sunflower! Thanks - so now I don't want to dig it up. It is an impressive plant and makes a nice screen. I did a couple of searches - native to tall grass prairie areas of the midest, starts blooming a bit sooner there, it barely beats the frost in my garden. How it got in my garden is a mystery - bird dropping I guess. Thanks again.

Helianthus salicifolius also has narrow leaves.

Hi Dave and all,

Thanks for the feedback on the ID suggestion. It's always good to hear back. I'm glad you're going to keep it. It's really nice.

Take care,
Grant

Maximillian sunflower ALSO has edible tubers raw or cooked. Adds some thickening power to stews :D

Vera