The senior partner and then chairman of NM Rothschild & Sons was a figure of international renown in horticulture, especially in the field of Rhododendron and Azalea plant hybridisation.
After World War Two, in 1946, de Rothschild set about the restoration of Exbury Gardens in Hampshire, the 100ha woodland garden created by his father Lionel in the 1920s and 1930s.
Over the next 50 years he replanted three-quarters of the gardens, and produced several dozen new Rhododendron hybrids. He also developed the highly successful Solent Range of Exbury deciduous azaleas, which are noted for their strength and colour. In 1955 he opened Exbury Gardens to the public.
In 2005 he received the RHS's highest award, the Victoria Medal of Honour.
A family funeral will be held on 23 January at Exbury Church and a memorial service later this year in London. A memorial garden could also be built at Exbury.