Rhododendron mucronulatum
(Not to be confused with Rhodo. mucronatum)
January 14th

This type of photograph is always a challenge! Against the rather strong sunlight; a light subject against a dark background; a bitingly cold morning etc... (Sorry I digress)
This Rhododendron amazes me in that it chooses to flower during the coldest part of the year. The fact that it originates from Russia and Mongolia may have something to do with it.
The flowers - which look rather tender and delicate - are anything but that. (If I had been a little earlier, then the photograph would have included the rather harsh frost of this particular morning). 

It is a dwarf shrub. This particular one - well mature, and un-restrained - has a height of about 1.2m, with a similar spread. It is best in full sun, though also does well as a semi woodland plant. 
It flowers before the foliage even thinks of putting in an appearance, from December through Feb/Mar.  As with other Rhododendrons, an acid soil is required.