The grounds associated with Highbury were mainly landscaped by Edward Milner, an Edwardian garden designer of national repute, and include, in various states of preservation: a long drive from the entrance lodge to the house (now overgrown); a formal semi-circular terraced garden (parterre) in front of the house; Kitchen gardens (with boundary wall built in 1879); pleasure gardens adjoining the house and ornamental gardens around the periphery; lakes, ponds and open parkland.

Important architectural features in the grounds include two lookouts, terracotta balustrades and a pergola, remnants of a fountain and the footprints of an ornamental dairy and hobby farm.

The grounds are included at Grade II on the English Heritage Register of historic Parks and Gardens of Special Historic Interest in England and Wales.