Children are plotting a horticultural coup at this year's Chelsea Flower Show, with junior judges and a "no adults allowed" garden.
The King and Queen will be joined by celebrities for the first glimpse of the Royal Horticultural Society's (RHS) event in London on Monday.
King Charles will visit the show's first garden to be co-designed by primary school children.
The show opens to the public on Tuesday.
A deal to let grownups on the RHS "no adults allowed" garden, which is not being judged, was secured after what was described as "tough negotiating" by the society's director general Clare Matterson.
Adults who want to see it must pledge to plant a tree to help the environment, donate to the RHS school gardening campaign, or find a flower that starts with the first letter of their name.
Youngsters are also being recruited to judge Chelsea Flower Show gardens for the first time, with 72 children from nine London primary schools participating as junior judges.
They will be asked to consider questions about the show gardens, including whether it is a good place to play, attractive to wildlife and how the spaces make them feel.
They will also be handing out a "children's choice" award.
Helena Pettit, RHS director of show, said: "We're super excited that we have our young children designers taking centre stage, who really want to encourage children everywhere to become gardeners, to help save the planet and have some fun.
She added she "can't wait to see which show garden our young judges pick as their favourite".
'Focus on sustainability'
There is also a focus on sustainability and climate change, with the event billed as "one of the greenest" in recent years.
Many of the gardens at the show have a direct focus on sustainability, with plants that are resilient to changing weather patterns.
All the large gardens have also gone through a "green audit" as part of efforts to reduce the event's environmental footprint.
Ann-Marie Powell, who designed the Octavia Hill garden, chose plants that withstand extreme weather, which are being seen as the climate changes.
"We all need to adapt the way we garden, with more unpredictable and extreme conditions in mind," she said.
Ms Powell changed her design after the frost-free spring led to some plants flowering earlier in the year than usual.
"This spring may have felt very cold to people, but it has been unseasonably warm from a horticultural point of view, because we haven't had the frosts," she added.
"The plants haven't had that pause during freezing weather, so they've kept going and flowered earlier than in a 'typical' year."
She said she was "really excited" to get the chance to work with beautiful plants not normally seen at Chelsea.
"I'm all about experimenting and having even more plants to choose from," she added.
"But this isn't just about nature throwing us a quirky spring... there's a pattern and we all need to adapt the way we garden, with more unpredictable and extreme conditions in mind," she said.
