I cut this winter heliotrope Petasites pyrenaicum (syn. L. fragrans) flower from the garden just before the snow arrived. Despite being native to the Mediterranean region it is very hardy in Britain, where it's widely naturalised, and produces new foliage and flowers in winter. The flowers have a delightful scent of vanilla, or maybe marzipan, depending on your sense of smell. Only male plants have ever been introduced so it never sets seed, but the creeping rhizomes can be very invasive so its root growth needs to be confined. Its widespread occurrence on road verges is most likely the result of fly-tipping of garden waste, by people who planted it in open ground and wish they hadn't.
Winter honeysuckle Lonicera fragrantissima is native to China and has a wonderfully intense fragrance during the day, unlike our native honeysuckle whose scent only develops at dusk, to attract crepuscular pollinators like hawk moths. This particular specimen is planted in a front garden in Durham city and scents the air for passers-by.