Hillier, which has won 70 Chelsea gold medals, will be elsewhere in the pavilion. The Hampshire nursery's managing director Andy McIndoe, who designed Hillier's Chelsea gardens, left the business last month.
Hardy's Cottage Garden Plants' Rosy Hardy has designed her first show garden, "Forever Freefolk", sponsored by Brewin Dolphin. It is inspired by endangered chalk streams in Hampshire.
New Covent Garden Flower Market makes its debut to the show with a floral installation exploring the symbiotic connection between the wholesalers of London's New Covent Garden Flower Market and independent professional florists.
Among the 100 exhibitors in the pavilion are newcomers Tom Smith Plants, Hoggarth Hostas, Plantbase and Love the Plot You've Got. Diarmuid Gavin is designing for Harrods at the triangle site with the British Eccentrics Garden, which will feature moving "Heath Robinson" topiary. Cleve West (M&G Investments) has a garden inspired by ancient oak woodland on Exmoor. Millais Nurseries will celebrate the centenary of the Rhododendron Society, which held its first AGM at Chelsea Flower Show in 1916.
Other gardens include Chihori Shibayama and Tea Yano (Watahan & Co), Chris Beardshaw has designed for Morgan Stanley, James Basson (The L'Occitane Garden), Jo Thompson (The Chelsea Barracks Garden), Hugo Bugg (Royal Bank of Canada Garden) and Andy Sturgeon with "The Telegraph Garden".