He is the son and heir of Guy and Sarah Hart Dyke at the family seat of Lullingstone Castle, Eynsford, Kent.

In 2000, Hart Dyke was kidnapped by suspected FARC guerrillas in the Darién Gap between Panama and Colombia while hunting for rare orchids, a plant for which he has a particular passion.

He occupied himself by creating a design for a garden containing plants collected on his trips, laid out in the shape of a world map according to their continent of origin.

The story of the creation of The World Garden of Plants was the subject of a BBC2 6-episode series, "Save Lullingstone Castle" (KEO Films) in 2006.

In May 2006, Hart Dyke brought an Australian Eucalyptus caesia plant, common name Silver Princess, to flower for the first time in the UK.