Cactus: houseplant of the month

The cactus is essential on a hot summer's day. Choose a spiky beauty with flowers, ridges or discs, or one that looks like it's make entirely from sharp green bullets. Don't worry about heading off on holiday — your cacti can help mind the house while you're away, even when there’s no watering to be had. Reward it on your return with a bit of extra food, but don't be tempted to stroke it!