The peonies are out in Kew Gardens, with staff and visitors enjoying their moment in the sunshine. But all is set to change, as Joe undertakes a massive year-long renovation of the peony garden. Meanwhile, the secrets of the peony are unveiled in Kew's Economic Botany Collection, where scientist Monique reveals the amazing healing properties of this underestimated shrub, and we find out about Kew's important work investigating the benefits, and dangers, of herbal medicine. It's also big change for Hélèna in the kitchen garden as all her precious vegetables are pulled up for a massive overhaul. Before she can get back and start replanting, Hélèna gets the unusual job of adding plants to some giantsized, mythical wooden trolls that have come to the gardens for an exhibition. In the glasshouses, Eleanor and Tom are playing with some deadly plants as they update the carnivorous plants section. We see Eleanor undertake some miniature landscaping and Tom introduces us to some scary plants with unusual carnivorous appetites. After the gardens close, we meet some of the people lucky enough to live onsite at Kew, such as head of tree collections Kevin, whose two boys have the best back garden any kids could have… even if Kevin does have to talk shop when he bumps into his boss Richard. In Sussex, at Wakehurst, Kew's wild botanic garden, Steven is keeping ancient traditions alive by making charcoal as part of his work managing the woodland. Meanwhile, Alice is working at the cutting edge, germinating seeds from the Millennium Seed Bank as part of Kew's mission to conserve all plant life in the world. We even meet a plant grown from a 200-year-old seed that was found in a wallet.

Winter leads to a carpet of snowdrops bringing in the visitors, and in the Rock Garden, Faye talks about the world of galanthophiles, the official name for snowdrop obsessives. In the warmth of Kew's glasshouses, Alberto prepares for his first orchid festival in charge, but luckily, he has help in veteran volunteer Henck. He and Alberto have set themselves the tricky task of creating a giant orchid sun in the middle of a pond.