JACK IS STANDING TO ATTENTION

Jack-by-the-Hedge is so called because it grows alongside hedgerows and, unlike most plants that lean away from competing vegetation it stands straight up.

Its other name is garlic mustard.  It's one of the few plants that smells of onions but is not an Allium.  

The round scalloped leaves help in identification before the white flowers appear.

This is one of the foodplants for caterpillars of the Orange Tip butterfly.  The eggs are laid singly beneath the flower buds and turn bright orange so they should be easy to spot.  But I've never found one.

Male orange tip nectaring on a dandelion
Photo: Alan Watts