Travelling back and forth by train between London and Hertfordshire I observe the onset of spring across thirty miles of countryside. The aforementioned Cherry Plum and Blackthorn are much in evidence with Hawthorn to come. As noted they are frequently the remnants and relics of hedgerows. 

 Consider the vista above. Scenic in its way but basically one huge field that would have been a patchwork of fields divided by hedgerows and tracks. Something of a hedge still exists alongside the railway line hence the blossom. Not much for pollinators across this swathe of open country.

 In some locales more hedgerows have survived or at least pockets of shrubs and trees that were formerly part of a hedge. Happily these three species form thickets quite readily so can perpetuate themselves to some extent.

 The window of a train can be a good vantage to picture a disappeared landscape by observing the bursts of blossom dotted here and there.