The name Caryopteris is usually associated with a bunch of rather grey twiggy subshrubs grown mainly because they flower very late in the season (C. x clandonensis and the like). C.divaricata is very different - making a lush green upright bush and dying down completely in winter. The late flowering is the same but the flowers themselves are much more interesting as can be seen from the photo. Those of you who know the tropical Clerodendron (or Rotheca) myricoides (or ugandense) would be right in thinking they look suspiciously similar, with those long curling filaments and rounded purple blue petals. They are related.
Another well-known purveyor of rare plants describes the flowers as merely ‘harmless’ which I think is a bit unfair. They’re not huge or especially plentiful, but they are beautifully crafted and jolly pretty. The only down side is the foliage which has an odd odour (one customer calls it The OXO plant) so don't plant it too near the path unless you like that sort of thing. Also the stems are quite brittle so best planted amongst other things out of the wind.
1L pots ~ £6