One of my favourite signs of spring is the Red Osier Dogwood, whose stems turn a bright red at this time of year. It's one of the few shrubs that seems to know that spring is coming. This is part of a large patch in a wet low area, just down the road.
The other tree that knows spring is coming is the willow, which turns a brighter yellow. Even if it weren't for the longer days and warmer sun, the willows tell us the seasons are changing.