The gardens that visitors see at Kelmarsh Hall today are largely inspired by Nancy Lancaster. She extended her interior style of shabby chic charm into the gardens and drafted in the garden designer of her day, the talented Norah Lindsay, to help. Around the Hall the landscape architect Geoffrey Jellicoe laid out a formal terrace.

A dahlia festival is normally held each September to showcase the varied collection in the walled kitchen garden. Over the last few years new American-bred varieties have been added to the collection, as a nod to Nancy Lancaster's American roots.