For a really early blaze of spring colour, consider Rhododendron ‘Praecox’. These Rhododendrons has been flowering their cotton socks off in the established gardens in my local area. But you don’t seem to see them often in new gardens, which is a shame as they are evergreen with dark glossy leaves, very low maintenance, and an easy size to fit in most gardens at a height and spread of around 1.3 metres. They like light shade (but are forgiving in other situations) and fully hardy. For the icing on the cake it has been awarded the RHS Award of Garden Merit.
Position them in your garden where you can be sure to see them from your windows and enjoy spring in your garden.