St George's Chapel will be decked out with white garden roses, peonies and foxgloves for the royal wedding.
Meghan Markle and Prince Harry have chosen floral designer Philippa Craddock to create the in-season displays for their big day.
Branches of beech, birch and hornbeam will be used in the decorations, with the locally sourced foliage coming from the gardens and parkland of The Crown Estate and Windsor Great Park.
The Royal Parks will also supply some pollinator-friendly plants from their wildflower meadows.
"The designs will reflect the wild and natural landscapes from which many of the plants will be drawn," Kensington Palace says.
After the wedding, the couple have arranged for the flowers to be distributed to charitable organisations.
Ms Craddock, a self-taught florist based in central London, with a studio in Fulham and a flower shop in Selfridges, described working with the royal pair as "an absolute pleasure".
"The process has been highly collaborative, free-flowing, creative and fun," she added.
"The final designs will represent them as a couple."
Ms Craddock's client list includes the V&A, Kensington Palace, Hampton Court Palace, Alexander McQueen, Christian Dior and British Vogue.
Australian Associated Press