'A Sense of Place' will showcase members' products and skills.
The Chelsea selection panel is considering the design.
In 2017, the HTA and Peter Seabrook had a Chelsea garden inside the pavilion with product and plants from more than 80 members, including garden centres and growers.
The HTA say a main avenue show garden will also be able to show off its Association of Professional Landscapers' members work.
Designer Tom Massey has also entered a show garden. He says the show is over-subscribed this year, though applications do not necessarily have sponsorship confirmed.
Gardeners' World presenter Mark Lane has tweeted: "Get behind me to design the first fully accessible show garden #chelseaflowershow."
Show sponsor M&G has a show garden confirmed after withdrawing from sponsorship, then re-signing.
Landscaper David Dodd is having a year off but fellow landscaper Jody Liggard has had a number of enquiries.