The new edition is published by the RHS, compiled by Richard Sanford and edited by John Hillier, Roy Lancaster, Neil Lancaster, Dawn Edwards and James Armitage, RHS principal scientist and botanist, who spoke of how he approached the task, but with more modern technology.
He and fellow RHS botanists soon lost evenings and weekends to the book, which they worked on alongside their day jobs.
"We knew right from the off we had to capture the authentic voice of the Hillier Manual," he said. "It has been so much a part of our lives for so long, we were excited to be part of something so big."
John said he and brother, Hillier chairman, Robert, had once slept in the room being used for the launch in the family's former home, now part of the Sir Harold Hillier Gardens, run by Hampshire County Council.
Meanwhie Jean Hillier, wife of chairman Robert, explained how she had researched the family history after retiring before going on to write her first book – Hillier: The Plants, The People, The Passion.
She was helped by 'the Hillier Archive", which was "two rusty old filing cabinets". In here were school books once belonging to Abner, brother of nursery founder Edwin Hillier, which contain pressed plants and notes by Edwin, and further notebooks used by Edwin as he learnt his trade as a journeyman gardener aged 14.
These showed he had worked at a number of gardens, including Cobham Hall, Kent and Syon House, now in west London and Osborne’s Nursery, before deciding to marry housemaid Betsy and buy a nursery of their own, when he was just 26 and she 29.
The leasehold of the Winchester property, found through an advert in Horticulture Week forerunner Gardeners Chronicle, cost them £200.
Jean Hillier, whose book, started as family history research with husband Robert 10 years ago said: "The Hillier family knew nothing about this, it was a revelation to them. Once we'd started the research Robert said to me we've got to start writing it down before it was forgotten."
Hillier The Plants The People The Passion is on offer at £14.99 until the end of May from www.hillier.co.uk, normal price £20. The Hillier Manual costs £19.99 and is available from the usual RHS outlets.