A look at Trsteno Arboretum in southern Croatia, which is perched on a limestone cliff and boasts a rich history that spans more than 500 years. The programme uncovers its opulent Renaissance origins, featuring ancient stone columns, sprawling ornamental trees, sun-drenched citrus groves and intricately designed maze-like shrubs.

A look at the German garden island of Mainau in Lake Constance, visiting the Dahlia Garden, where an astounding 12,000 flowers bloom across 280 varieties. Also featured are 3D floral installations, including a giant peacock, an innovative 1,700 square metre rooftop garden teeming with more than 16,000 plants representing more than 300 species, and one of Europe's largest butterfly houses.

A look at the palace and gardens of Parque de Monserrat in the Portuguese town of Sintra, which span 80 acres and are a testament to the Victorian era's adventurous spirit of plant collecting. Featuring the sun-soaked Mexican garden, where towering cacti and vibrant blooms create a dazzling spectacle, and Fern Valley, a shaded paradise alive with lush tree ferns from Australia and New Zealand

A look at the continent's finest horticultural sites, beginning with the Dutch city of Leiden's Hortus Botanicus, one of the world's oldest botanical gardens. The programme reveals its role in sparking the popularity of the Dutch tulip and explores how it transformed European horticulture with exotic plants from the Far East, and examines its legacy in medicinal research