A couple of years ago, I went through the RHS book looking for some new perennial plants to grow in the garden and I found these two (amongst others) and they are great performers.
They flower profusely throughout the growing season and I don't know why more people don't grow them.
The name is Erodium Pelargoniflorum and the only thing it doesn't like is being moved.
The next one is my favourite as it doesn't stop flowering until the frosts.
Just keep removing the spent stems all the time and they pull away really easily. This is called Erodium Manescavi.
Finally, this little beauty is one of my favourite climbers and this is the first flower it's borne this year which came out today.