Somewhere I have a copy of an old book on botany book called "Wayside Weeds and Wildflowers". That title has always stuck in my mind when I'm out and about. The wayside is indeed a good place to spot those plants which may be called weeds or more accurately wildflowers.

 White Comfrey (Symphytum orientale) seems to be becoming more and more prolific in that regard, at least in North Hertfordshire. This form of Comfrey is native to the Eastern Mediterranean originally so the recent dry summers may have helped; likewise the calcareous/sandy soils hereabouts. Actually it is worthy of a place in any garden though I'm happy to see it by the wayside.