Got a problem in your plot? Let our Garden n Guru Martyn Cox ox help you out

Q I keep seeing ‘grafted’ tomato plants in garden centres. What are they? Jon Pacey A These are a fairly recent addition, with two varieties joined to make a single plant. The roots belong to a vigorous species, while the top is a variety known for its tasty fruit. It results in a fastgrowing, more productive plant. Due to the propagation process, plants cost more than seed-raised ones. Q I planted a wisteria against a west-facing wall three years ago. It produces lots of foliage but no flowers. What can I do to get it to bloom? Laura Greene Wisteria will often grow rampantly if left to its own devices, producing masses of leafy growth at the expense of flowers. Pruning is necessary to divert energy from making foliage into producing flower buds. Prune twice a year, in July and late winter. Plants grown from seed can sometimes take 20 years to bloom. Always buy plants that are in flower. If you have a question for Martyn, email info@martyncox.biz