After years in the doldrums, the dahlia has become popular again.
Not before time, reckons Monty Don, who praises its variety, long flowering season and adaptability.
It even makes a great cut flower.
At Longmeadow, Monty shows us how to get dahlias and other tender perennials under way for the summer, while Adam Frost heads to Dorset to meet a tropical-plant enthusiast with a garden full of exotic and unusual specimens.
Please note this programme airs at 9.30pm in Wales.