– Don’t let your garden slump into autumn, keep it fresh. Take the dead heads off late perennials to keep them going until the autumn leaf colour arrives: dahlias, cosmos, rudbeckias, helianthus, heliopsis, helenium. Put a can of liquid feed on potted fuchsias and late chrysanthemums.

– Now is not a bad time to take rose cuttings. Take 9-12in lengths of vigorous, firm new growth (that excludes the soft tip) and push them in somewhere shaded and moist. Don’t expect results before next April.

– Divide water irises such as sibirica, pseudacorus, ‘Gerald Darby’ and chrysographes. To be economical with precious varieties, break into small clumps of three to four rhizomes, rather than individual ones. Old clumps of tough varieties can just be hacked into wedges with a spade and replanted.

– Before the damp, colder autumn weather arrives, get a coat of preservative on fences and garden furniture that is starting to look lean and dry (no need to do it every year). If you are using an oily preservative, you may want to leave it till the end of the season when the chairs are out of use.

READERS' QUERIES

I planted a yew hedge last spring and the plants seem to be different shades of green. Do they need feeding? Mr R. Benjamin, Edgbaston

Frustrating, isn’t it, when you want an even, formal hedge. You may find the new growth in spring is even more varied, occasionally almost bronze, because you have bought mixed or seed-grown stock; feeding won’t alter a thing. For the average hedge it doesn’t matter but, for perfect formality, it’s best to ask for identical plants from cuttings of the same clone, grown for hedging.

Our golden Robinia ‘Frisia’ is less than ten years old and was growing well, until last year when it suddenly started to lose some of its lower foliage. This year it has hardly come out at all and there is quite a lot of dead wood. It replaced a very mature flowering cherry tree that we lost in a similar way, which we were told at the time was caused by drought. What’s happening? Mr K. Norris, Solihull

What a miserable tree your picture shows. The problem is almost certainly root disease. It could be honey fungus, but that usually causes a tree to pack up pretty quickly rather than over several seasons. It absolutely loves a cherry tree, but then serious drought can bring a senescent cherry to a shabby end, too. If there is honey fungus in the ground, it would certainly enjoy being fed a fresh young robinia, pudding to its cherry starter.

Phytophthora is the other common root killer and it is especially prevalent in wet ground, of which we had plenty last year. Equally, waterlogged ground can cause roots to die back (and subsequently branches) simply from drowning.

Test for honey fungus by cutting back an inch of bark at the base to look for the white sheath underneath. If it’s there, take the tree out, stump and all, as soon as you can face the mess. If not, be patient, give it another season and, if it’s no better when coming into leaf next year, have it out. Does your garden need drains putting in?

stephen.anderton@thetimes.co.uk

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