Scotland's gardening series returns for another season to dig up pearls of wisdom from the past and Jim McColl, Carole Baxter, Lesley Watson and Carolyn Spray give out advice for the present. Carolyn sorts though the mail order mayhem of plug plants online, while the others catch up with how the garden has fared and developed over winter. Carole visits one man's dream of a million little gems, in this case its snowdrops at Ecclesgreig Castle near St Cyrus.