Garden Guru

Some of the little tubers have broken off the main body of a clump of dahlia tubers. What can I do with them? Dinah Price Sadly, not very much. A tuber needs a shoot or bud above it to grow, so if the sausage structure has broken off on its own, then it’s of no use and is best consigned to the compost heap. Last year the buds on my rhododendron turned brown and didn’t open. Have you any idea what might have caused this, and is it likely to happen again this year?

Margaret Fisher It’s possible that your plant will be attacked again by bud blast, a fungal disease that causes buds to die prior to flowering. It’s spread by leafhopper insects, and the best way to keep it in check is to remove and destroy infected buds before the pests arrive in the summer. I live in a hard-water area and wondered whether it is OK to use tap water to mist the leaves of houseplants. Gillian Wilkinson Tender ferns, peace lilies, bromeliads and a host of other houseplants like humid conditions and respond well to regular misting. Using hard water to do this certainly won’t harm the plants in any way, but whitish marks will build up on foliage over time. Don’t worry, though – these can be rubbed off with a soft, damp cloth.