There will also be a sneak preview of three new gardens being designed for RHS Garden Wisley in Surrey, while world-renowned designer Tom Stuart-Smith returns to Chelsea for the first time since 2010 with his garden for the Garfield Weston Foundation charity.
The foundation is donating £5million to RHS Garden Bridgewater, which opens next year in the grounds of historic Worsley New Hall in Salford, near Manchester.
Stuart-Smith is leading the team restoring the “lost” garden’s 11-acre walled kitchen garden and creating a new horticultural oasis in the North.
As for the other gardens, RHS Director General Sue Biggs CBE, says there will be a full complement when the show opens on Tuesday, finishing on Saturday.
“We did have some challenges last year with the shock of Brexit and what was going to happen,” she admits.
“But we are back up to full strength with 29 gardens this year.”
Main Avenue will have 10 show gardens, from well-known names such as Chris Beardshaw and Mark Gregory, with Sarah Price designing the prestigious M&G Garden for headline sponsor M&G Investments.
A new category called Space To Grow replaces Fresh Gardens and 10 gardens will run along the front of the Royal Hospital Chelsea, home to the Chelsea Pensioners.
Space To Grow will inspire gardeners with small urban plots and among the designers are Kate Gould and Dr Catherine MacDonald.
In previous years a lack of female designers at Chelsea has led to criticism but Sue Biggs says: “We didn’t do this deliberately but we have 15 male and 15 female designers.
“It isn’t that the gender gap is closing, the gender gap has closed; everybody can come and design and win medals at Chelsea.”
The ever-popular Artisan Gardens under the London plane trees have eight entries and among those to look out for is the Viking Cruises Garden by award-winning Paul Hervey-Brookes, who has been an RHS judge.
His tips to new designers: “Try not to think about gold medals. The main thing about making a garden that gets gold is that it has to be full of integrity from the start.”
The jewel in the RHS Chelsea crown is, of course, the Grand Pavilion, where 90 of the world’s best nurseries will be exhibiting.
There will also be a NAFAS floristry exhibition and Flowers From The Farm – British cut-flower growers from Cornwall to the Scottish Highlands – will make their first appearance.
The wow factors are likely to come from Tom Stuart-Smith’s Garfield Weston Foundation garden, Sarah Eberle’s massive Hillier garden, Birmingham City Council’s Windrush garden – complete with a ship – and floral tributes to Prince Harry and Meghan that will decorate the Pavilion’s doorways.