Stocking a garden with plants can be an expensive business, so there are few things more frustrating than when the prized specimen for which you have paid a king's ransom either online or at a garden centre shrivels up and dies within a year or so of purchase. If you can prove that the plant was half-dead when it arrived, you may able to obtain a refund from some online retailers, but for the most part you have to put it down to experience and make...