Red Valerians — The Beauty & The Danger

Red valerians abound these days on walls, riverbanks, chimneys and roof barges.

They do add to the colour of the often long grey monotone of a wall.
But there’s no doubt that they do serious harm also, as their roots grow strongly under mortar plaster and between stones or bricks.The resulting bond is weakened – often destroyed – and the emplacement will fall in time.

The spores of these weeds seem to spread through the air like those of eosadáin : no doubt the spores of these ones in the photo below will carry onto neighbours’ walls in time.
Yet there seems to be no corresponding directive to property owners to actively destroy valerians seen growing on their buildings.

These three bunches have loosened the capping course and are literally peeling back the roughcast plaster on their ‘home’ wall.

What do you people think about these weeds ?

Should they be covered in new property maintenance regulations ?

Or is an entirely new section of the Building Control Act needed ?