Hypericums can seem a bit ho-hum to most keen gardeners I admit but there are some interesting ones. In this case I think the appeal is in the distinctive low rounded habit and the contrast of the fresh yellow rounded flowers with the neat elliptical sea-green leaves. Like other shrubby Hypericums though, it's easy to please and flowers over a long period in summer. Not at all weedy, and completely hardy.
1L pots ~ £6