Kensington Palace has released a series of heartwarming new photos of the Duke and Duchess of Cambridge and their children celebrating the opening of the Chelsea Flower Show.

The pictures show Prince George, Prince Louis and Princess Charlotte playing in the dirt and enjoying the natural beauty of the “Back to Nature” garden their mother, Catherine, helped design for the royal flower show.

“There’s an amazing fact that I learnt recently was that 90 per cent of our adult brains are developed before the age of five,” Duchess Catherine said in a video released Monday.

“What a child experiences in those early years directly affects how the brain develops and that’s why I think it’s really important that all of us—whether we’re carers, or parents, or family members—really engage in quality time with children and babies from a really young age.”

Inspired by her passion for childhood development, the garden uses natural materials and plants to create a woodland wilderness where children and adults alike can feel closer to the great outdoors.

Prince Louis, who turned one in April, was pictured practicing his walk through the garden and enjoying a ride on the rope swing with the help of his father.

Prince George and Princess Charlotte were seen dipping their toes in the babbling stream that runs through the greenspace. With muddy feet, Charlotte, who turned four earlier this month, also played on the rope swing.

“I really feel that nature and being interactive outdoors has huge benefits on our physical and mental wellbeing, particularly for the young kiddies. This is a natural, creative place for them to play,” the Duchess added.

“I really hope that this woodland that we have created, and the huge collaboration here, really inspires families and kids and communities in general to get outside.”