What type of hedge is best for trapping pollution? Which hedging plants help mitigate flooding risks? Can you grow roses and clematis together to make a flowering hedge? We went to a recent 'Hedging Your Bets' event at RHS Garden Wisley to find out more. Plus the Gardening Advice team gathers to answer queries on houseplants for a shady bathroom, growing houseleeks and aeoniums, the secrets of making great compost – and whether you can grow your own wasabi peas?!