Wintersweet lives up to its name. This straggly/bushy shrub bears sweet-scented flowers in winter. Chimonanthus praecox hails from China; the RHS rates it as H5 "hardy in most places throughout the UK, even in severe winters (-15 to -10)". Often grown against a wall receiving full sun.

 I was working in the vicinity of Wintersweet earlier today, a long established specimen with many flowers on many stems. The air was suffused with its heady fragrance.