I am obliged to deal with a lot of hostility when defending my right to object to a Public Right of Way being claimed to go through my garden. I often wonder why it is that the same people, who criticise me, see absolutely no parallel with others who take great objection to the grass verges outside their boundary fences being driven over by vehicles trying to pass in a narrow lane.
The verges of roads are part of ‘the Highway’. Rocks, wooden posts and shrubbery are an obstruction.
Highways Act 1980
Powers of highway and local authorities to plant trees, lay out grass verges, etc.
No tree, shrub, grass verge, guard or fence shall be planted, laid out or erected under this section, or, if planted, laid out or erected under this section, allowed to remain, in such a situation as to hinder the reasonable use of the highway by any person entitled to use it, or so as to be a nuisance or injurious to the owner or occupier of premises adjacent to the highway.
What is more, no amount of obstruction to a highway, for however long will destroy the highway (Harvey v Truro Rural District Council 
Vanderpant v Mayfair Hotel Co 
An encroachment on a highway is by common law a public nuisance. It is no defence that the obstruction is made on a part of the highway which is not habitually or ordinarily used for passage. It is no defence that the obstruction is in other ways productive of public benefit, and however reasonable may be the use of a highway by an owner of adjoining premises the public right is a higher right than his and he must yield to the public right.
Owners or occupiers of properties next to the highway can apply for a licence to plant and maintain shrubs, plants or grass at that location.
Application to plant or maintain a grass verge (cultivation licence)
Shrubs must not be planted nearer than 5m from the centre-line of the road, and additionally, as necessary, no nearer than 1.5m from the edge of the road. Where there are footways between the planted areas and the edge of the road, planting shall be no nearer than 0.5m from the edge of the footway.
The types of shrubs that are proposed for planting on the highway verge should be discussed and agreed with the Highway Arborist beforehand.
NCC “We sometimes receive reports of verge erosion in rural areas. It’s not illegal for drivers to use verges, and normally the grass will recover in the spring.” https://www.norfolk.gov.uk/roads-and-transport/roads/road-maintenance/trees-hedges-and-grass-verges
Would the same people who try and ‘protect’ a grass verge which is already a public highway not just as strenuously protect their own garden?