Winter Aconites (Eranthis hyemalis) are bulbs -or more accurately small tubers- that flower with the Snowdrops and like the Snowdrops they're early this year. I've tried to introduce them in various parts of the garden but only a few here and there have stood the test of time which is disappointing. All the more so because the ones that do appear (as above) are a welcome sight with their golden yellow flowers.
 Seems like they don't prosper in damp heavy clay soils which are characteristic of London but they naturalize well elsewhere. I took the photo below several years ago in a village in Hertfordshire. Here the soil is lighter, chalky and free draining which is probably more reminiscent of their natural habitat in calcerous woodlands from southern France across to the Balkans.