Mahonia species are evergreen shrubs that grow as far apart as the Himalayas and Asia (e.g. M. japonica which is actually from Taiwan) and North and Central America (e.g. M. aquifolium aka the Oregon Grape). They've been introduced to the UK as garden plants mainly in the form of various Mahonia x media hybrids with names like "Winter Sunshine". The above is probably one such cultivar seen here in my local park.
 These are tough, spiny woodlanders in their natural habitats and winter flowering. The almost fluorescent spikes of yellow flowers are said to be fragrant though I can't say I find that particularly noticeable. Bumblebees however will come out of hibernation when they flower and seek them out so the scent and colour must be a potent lure.