Gardeners World episode 12 2002: Alan Titchmarsh gets going on a new project this week when he starts planting a colour-themed, fragrant border.     Gardening show packed with good ideas, tips, advice from experts and timely reminders to get the most out of your garden, whatever its size or type.   Gardeners World episode 12 2002   How to grow citrus fruit Citrus are not hardy in Britain but can be grown in pots outdoors in summer and brought…