Aquilegia; Columbine :
Aquilegia self seeds easily so it will pop up everywhere. Having said that, it is not a thug or an overpowering plant and usually shoehorns itself into a space without upsetting its neighbours too much.
There are hundreds of varieties, but they will cross fertilise and hybridise, so you may end up with a different plant than the one you originally bought.
We haven’t used this in any of our small garden designs, yet – but we do use lots of other plants that are much better (we think).
Why don’t you take a look
(Main image: C Meyer)