This week we've a bumper crop of help and advice to get your garden into shape for autumn. RHS experts give timely tips on everything from picking seasonal bedding plants, smartening up your plot, growing lemons and how to prune a purple-leaf elderberry. Horticulturist and TV presenter Flo Headlam gives a garden designer's take on how to get the best from your garden in autumn and shares her favourite plants for late-season impact.