Adam Frost demonstrates how to build a rose arch, mulches his beds and plants a blackcurrant to train up a fence.Frances Tophill visits RHS Wisley in Surrey to witness the seasonal colour that heathers can provide in the winter months. Carol Klein immerses herself in a sea of roses at Hanham Court Gardens near Bristol, and there's a touch of the Mediterranean in Devon as Toby Buckland harvests a crop of home-grown olives.There's a catch-up with three sisters from Dorset as they plant up their new borders and a visit to a spectacular display of tulips in Norfolk, as well as a chance to see what viewers have been getting up to in their gardens.