A powerful Country Diary column here written by Matt Shardlow, the chief exec of Buglife, about protected road verges in Rutland.
For some of these plants, like sulphur clover Matt writes that these polluted verges are their primary sanctuary.
He also references this Plantlife report from 2017 on road verge plants.
Over the last month Twitter has been full of photos of poorly managed (for wildlife) road verges, so great that there are some protected road verges, but I don’t think careful verge management should just be in the hands of Local Councils without challenge and oversight from the local community.