That looks just like a herbaceous clematis i used to have.
Not sure though if it's the same.

is it one of the nightshades? it doesnt look like my herbaceaous clematis, but it is such a big group......

Looks like a shoo fly plant to me, or Nicandra Physaloides to give it its proper name, is a member of the nightshade family SBG.

Yes, nicandra physalodes, yet another member of the same family as Thorn apple. Lots of those in recent GOY questions. Phil J

Yes, lots of these recently.

I think in order of questions commonly asked it runs like this....

No1. Cordyline dying (earlier part of year), Cordyline sprouting from base (latter part of the year).

No.2. Plant id. Datura stramonium - Thorn Apple.

No.3. Plant id. Nicandra physaloides.

thankyou all for ur help

I was one of those who put a picture of Nicandra Physaloides on the sight, because it had grown in my garden for the first time and I'd never seen one before! I now have three of them and loads of seeds if anyone wants them. They seem to like our soil because they've grown very large---about 1 metre wide by two ft. high! i've had to cut them back as they've taken over that part of the garden!! I suppose a bird must have dropped the original seeds, although the seed heads look a bit toxic to me!! Annie