Althaea officinalis - Marsh-mallow
This plant, though more common in the south of England, is very uncommon in Lanarkshire. It is described as nationally scarce in the UK.
This record in vc77 is probably a garden throw-out, although it was disyant from houses, on the banks of the Clyde.
It stands tall and straight, softly hairy throughout, with pale pink petals and shallowly-lobed, pointed, toothed leaves.