At London's annual Chelsea Flower Show, the flora is fit for a queen: shaped in her likeness and crafted in honor of her 90th birthday. The new princess has her own chrysanthemum too.

But this year's event, which opens Tuesday, kicks off with a warning from the Royal Horticultural Society: Britain has a "lost generation of gardeners."

Many people in their mid-20s to 40s never learned how to garden, "and we lost a lot of the skills," RHS Director-General Sue Biggs tells London's Times . The AFP news agency adds :

"Fewer than one percent of parents were taught gardening at school, compared with 55 percent of grandparents and 40 percent of children, according to a survey conducted by the RHS in 2011."

Against this backdrop, the Royal Horticultural Society continues to pursue its more than 200-year-old mission to "enrich everyone's life through plants."

As part of its campaign to beautify Britain, a featured exhibit gives visitors tips for their own gardening adventures.

"Gardens and gardening do more good to heart and soul than they are ever given credit for," designer Ann-Marie Powell told the RHS .

The 100-plus exhibits in this year's show range from whimsical to traditional — and they don't fit neatly into pots.

A sea of knitted and crocheted poppies covers the Royal Hospital grounds, much like a 2014 installation of ceramic poppies at the Tower of London, honoring soldiers who died in World War I.

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