Novice/reluctant gardener here.. I'm looking for plant recommendations for a
low maintenance border. The border is about 3ft wide by 12ft long and faces
east. It's got a wall 18 inches high behind it (eg along the long side and
one end). The soil isn't bad but has some clay and probably nettle roots
(although mostly removed). Currently covered with a new membrane and
awaiting plants and bark mulch.

My ideal plants would..

Grow to about 18" or 2ft high max and don't need much pruning.
Produce flowers or coloured leaves or both at various times of the year
Probably have no thorns
Ideally would be evergreen so the border isn't bare in the winter.

I've had a stroll around two local garden centers but many of the plants
I've seen are predicted to grow too big according to the labels. In the past
I've planted of Fushias but I need advice. The garden center staff haven't
been much help.

Is there a web site where you can search plant data by size etc?

Any help much appreciated.