In the garden

I've been thinking about what to do with the garden, and this plant is growing along the edge of the path, I have no idea what it is but I'm sure my Dad has had it before. Anyone know - should I keep it or replace it with something pretty, I really want lots of flowers, so I can take loads of photos and bore you senseless, but I would like to know what this is before I decide.

The weather has been lovely today, we had a fire drill this afternoon at work and I didn't have a jacket - and it was warm enough anyway so hopefully spring really is on it's way