Royals Kate Middleton Steps Out in the Perfect Floral Dress to Unveil Her Latest Garden Design The Duchess of Cambridge arrived on a tractor trailer alongside a group of excited kids and Mary Berry from the The Great British Bake Off By Simon Perry Published on September 10, 2019 07:58 AM Share Tweet Pin Email Kate Middleton proudly showed off her latest garden design on Tuesday! The royal mom of three, 37, unveiled her third “Back to Nature” garden, which supports her ongoing campaign to encourage kids to play outside. The royal believes that spending time outdoors plays a pivotal role in children’s future health and happiness, building foundations that last through childhood and over a lifetime. Kate was perfectly dressed for the occasion in an elegant pale green belted long-sleeved seersucker dress decorated with a pink floral print by Emilia Wickstead. She also wore her go-to tan wedges. The garden at RHS Wisley is a bigger and permanent version of the original design that she and her three children — Prince George, Princess Charlotte and Prince Louis — helped launch in May at the Chelsea Flower Show. Located about 25 miles southwest of London, it comes with a huge treehouse, a sandpit and swings. Kate Middleton. Chris Jackson/Getty Images Kate invited members of some of the charities and organizations she works with that support children to join in the festivities on Tuesday. She even arrived on a tractor trailer alongside a group of excited kids and Mary Berry (an ambassador for RHS) from the The Great British Bake Off show. The royal even thanked the tractor driver, telling her: “Thank you, well done. The kiddies loved it!” Princess Kate has spent much of the last eight years highlighting work that benefits children’s well-being. Kate Middleton Debuts Bouncy (and Lighter!) Hair at Princess Charlotte’s School Drop-Off — All About Her Fall Makeover! During the event, Kate also played with some of the children before she made a short speech. “As many of you know, I was invited by the RHS to co-design a garden for families and children for this year’s Chelsea Flower Show and Hampton Court Palace Garden Festival,” she said. “It’s been the most amazing experience and I can’t thank the RHS enough for giving me this wonderful opportunity.” “I am not as green-fingered as many of you here, but I was passionate about creating a garden that inspired children and adults alike to get back to nature and reap the positive mental and physical health benefits that it can bring,” she added. Kate Middleton. Chris Jackson/Getty Images “Whether it is planting, exploring, digging, creating, or playing; quality time spent outside provides children with the perfect environment to form those positive relationships with the people in their lives and the world around them. “As a parent, I have learned just how important it is to foster our children’s development, in all areas, not just physical, as soon as they are born. We build the blocks, the foundations, for future success and happiness later in their lives.” Kate Middleton. In May, her original design, which she created with designers Andrée Davies and Adam White, had caught the imagination of her own kids when they toured it at the Chelsea Flower Show. Kate Middleton. When he was asked by dad Prince William to give the garden a score out of 10, George, 6, said loyally: “20!” “Twenty out of 10?” William responded with a laugh. “That’s pretty good. I think Mummy’s done well.” Matt Porteous/PA Prince George and Princess Charlotte. Matt Porteous/Kensington Palace via Getty Back in the spring, Kate told the BBC’s gardening expert Monty Don, “I really feel that nature and being interactive outdoors has huge benefits on our physical and mental wellbeing, particularly for young children. I really hope that this woodland that we have created really inspires families, kids and communities to get outside, enjoy nature and the outdoors, and spend quality time together.” Can’t get enough of PEOPLE’s Royals coverage? Sign up for our newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! In July, the garden was moved to Hampton Court Palace for the summer garden festival. There. she unveiled the space with children from some of her charities and patronages, including the Anna Freud Centre, Evelina Children’s Hospital, Action for Children and Place2Be, taking part in an insect-spotting activity and joining in a treasure hunt.