Hi, Sheila...it looks like Aquilegia (columbine). I have had it growing wild around my boundary and have pulled like mad - to no avail. Decided to leave it be as it's quite pretty...but then it's not actually in my garden!

Thanks for you reply Karenfrance. It was already in the garden when we moved here and the vendor said it was gypsophila. It gets small white flowers on it (not at all like aquilegia) and has a fern-like leaf. It disappears completely in the winter then re-appears in spring. As I say, it takes over the whole area where it is.

That is not an Aquilegia leaf. Looks more like a Geranium possibly G robertianum var. celticum if it has white flowers. Mind my eyesight is not what it was.

I think it's Thalictrum aquilegiifolium, Sheilar. I have it in my garden, too - it's a real thug, and I've tried to get rid of it to no avail. The 'flowers' are so tiny that I don't really notice them - is that right?

Thought T. aquilegifolium had blue flowers? How tall does this plant grow? T.a. gets to about a metre.

I thought Thalictrum and I have seen them with white and yellow flowers too.

Owdboggy - I would say it grows to about 18" tall but it's difficult to tell as it's in a raised bed and sort of tumbles down over the wall. In one place, it has gown up against a rose which is about 2' high.

Spritzhenry - The flowers are tiny and insignificant, just as you described. It's so invasive it's now even started growing in between the block paving stones!

I've got this plant too and I don't know what it is either. I've grown Thalictrum aquilegifolium and this isn't it - it's much shorter. I've never seen flowers on mine.
It's definitely not aquilegia, and I don't think it's gypsophila either as gyp leaves are straight.

There are several different forms of T. aquilelegifolium. I hoped I'd put this plant into my plant list, but sadly I didn't when I found out what it is.

Sorry I can't give you its full name, Sheilar. I wish I hadn't got it, though, and I'm sure you (and Beattie) feel the same!

Thanks everyone for your comments. I think I'll have another go at digging it out or at least keep it under strict control, as it's smothered so many other plants in the past.

Good luck. I'm going to do the same, as it's in amongst my Anthemis now. :-(

Good luck to you too Spritz - I think you'll need it!

Yup. :-((

Mine's under a flowering currant bush - where I will leave it. If it spreads too much it can duel with the japanese anemones further along.

how about thalictrum majus 'greater meadow rue' or T. flavum 'meadow rue'. both it the description and both creep according to my wildflower book.

I have T.flavum in another flowerbed and more than twice the height of my specimen of the plant under discussion. It's possible that Sheilar and I have different species, but I think everyone who suggested Thalictrum is on the right track. According to Wikipedia, there are 120 - 200 species of Thalictrum - who'd have thought there could be so many?
My best guess for my plant is T.minus.