This licence is recorded in the Calendar of patent rolls (1343–45),[2] The inhabitants of the castle, the de Hagardestons, are believed to have been part of the 11th century invading force of William the Conqueror, which penetrated as far north as Berwick-upon-Tweed.

On his death in 1891 it was inherited by his nephew Christopher John Naylor (1849–1926), who gave up his family home, Leighton Hall, Powys, to his brother and moved to Haggerston—changing his name to C.J.

By 1893 Leyland had rebuilt the main house and had begun developing his own gardens at Haggerston, overseeing the landscaping of the 23,000 acres (9,300 ha) estate.

Leyland (née Naylor) died in 1926; in 1933, attempting to recoup some of the family fortune, the ruins of the house he built were demolished and the estate was auctioned off in 2,000 lots.

While developing the gardens and landscaping at Haggeston, Christopher Leyland was sent by his brother John, six Cupressocyparis × leylandii, a hybrid tree that was the result of spontaneous cross-pollination at Leighton Hall in 1888 when the female flowers or cones of Nootka cypress (Cupressus nootkatensis) were fertilised by pollen from Monterey cypress (Cupressus macrocarpa).

[5] In 1925 a firm of commercial nurserymen specialising in conifers were looking for a particular breed; one that was fast growing and could be deployed in hard-to-grow windy and salty areas such as Cornwall.

[6] In 1953 a freak tornado blew down one of the original trees; subsequently the Forestry Commission started developing hybrids from the five survivors.

Commercial nurseries spotted the potential of the now termed "Leylandii", and it is one of the biggest-selling items in garden centres in Great Britain.