The only company that has exhibited at Chelsea every year since the original 1913 event celebrated with the launch of Delphinium 'Chelsea Gold' at this year's show before taking the prestigious President's Award.
Bristol-based Blackmore & Langdon, founded in 1901, is owned and run by John and Rosemary Langdon, who are officially retired, and their sons Simon, Stephen and Nicholas, great grandsons of founder Charles Langdon. The Blackmore side of the business only survived two generations.
Rosemary Langdon said: "Chelsea is very important to us - a high-prestige show. We feel the public rates Chelsea.
"If you can get there and show there you have got to be all right. If we dropped out we'd still carry on growing the same plants and if the money ran out we'd have to drop out but otherwise we'd never consider not doing Chelsea.
"Chelsea has changed hugely. John and I are in our seventies and we've been involved since the late 1950s.
"Back in those days and earlier, head gardeners and owners of big estates placed orders at Chelsea, but now the man in the street is able to buy the things he likes for his own garden. Previously it was only the wealthy who could do that."
Blackmore & Langdon operates by people visiting the nursery and via mail order. It supplies Highgrove, Royal Parks, National Trust and White Flower Farm in the USA as well as the Canadian, Australian, Japanese and New Zealand markets. The firm has won around 70 Chelsea Gold Medals.
The company insists that it has shown at all the RHS shows despite RHS historian Brent Elliott saying otherwise in an official book, RHS Chelsea Flower Show, A Centenary Celebration.
Rosemary Langdon said: "The only thing that is a little bit sad is the Chelsea Flower Show book comments that no one firm has done every Chelsea Flower Show, but we're pretty sure we've done them all.
The RHS said: "Blackmore & Langdon has indeed attended every show since 1913. Brent has checked some other records, which show he made a mistake."
Distinguished service - long-established Chelsea exhibitors
Kelways was founded in 1815 and has been showing peonies at Chelsea since 1913. Director Dave Root and his team now also source and grow plants for show gardens including Michael Balston, James Basson and Flemings Nurseries. The Somerset nursery has missed 10 Chelsea shows since 1913.
McBean's has been at the show in some form every year for the 100 years but the East Sussex orchid grower, founded in 1879, is the third to still exist from Chelsea 1913.
Manager Jim Durrant said: "We're trying to replicate our original group of 100 years ago with very old-fashioned tiered staging and old-fashioned varieties." These include Cymbidium lowianum, shown at Chelsea in 1913.
McBean's has been owned by the Johnson family since the mid 1960s. Durrant said: "There's a couple of years where we were not there under our own name, either under British orchid growers, but we have either been there or had plants or personnel there every time."
He added: "The RHS knows that we missed three years - one year because there was a group of orchid growers exhibiting and I think in 1928 there was a big exhibition, so we joined with that."
Hillier, established in 1864, has now won 68 consecutive Gold Medals, a record, but was not at the first Chelsea.
The RHS Chelsea Flower Show opened on 20 May 1913. The show was cancelled in 1917, 1918 and 1940-46.