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Thorny problems: floppy flowers (Filed: 14/07/2001)

Gardener and lecturer Helen Yemm on how to find miniature versions of old favourites

Neater nepeta

After many years of having a garden with herbaceous borders and a lawn, I have moved to a house with a courtyard garden. Nepeta 'Six Hills Giant', which I adore, is too big and floppy for my new garden. Where can I get hold of a really tiny version? Peta Ellice-Clark, Petworth, Sussex

I GET so much correspondence about nepeta - it is clearly a much-loved plant. Your best bet would be Nepeta mussinii (also known as N. racemosa), although it is much less cat-resistant (cats can demolish small emerging shoots at one sitting) and generally not as hardy as 'Six Hills Giant'. The smallest of all is 'Little Titch', which is sold at Merriments Nursery, in Hurst Green, East Sussex - not a million miles from you.

Plant catmint in the sunniest possible site in your courtyard, and perhaps protect its growth each spring from nibbling, rolling cats with a "helmet" of chicken wire. As with your 'Six Hills Giant', once its wonderful blue has faded, take the shears to 'Little Titch' and it will come back into flower within a few weeks.

Privet pruning

I have a privet hedge about 16ft high and 6.5ft wide. I want to reduce the height by about 3ft and the width by about the same. When should I cut it? Roy Gourlay, St Agnes, Cornwall

Privet grows at an alarming rate. To prune it by 3ft, you should, perhaps aim to reduce it by more so that you will not be endlessly cutting it back to blade-blunting stumps. You will no doubt be cutting into the brown wood.

The best time to tackle this job would have been in early summer, when the recovery of the foliage would be swift. However, since privet is so tough and vigorous - and you live in the South-West, where it has a long growing season - you could tackle the job now, or at least before the middle of August.

As long as we are not facing an intense period of drought, you should find that your privet will have greened up again in no time. It may need a light trim in early autumn to neaten up any unevenness that may result from such a shock. Feeding, watering or applying a mulch to the base of such a vast hedge to aid recovery would be a waste of time and energy.

Away with the fairies

A number of correspondents - among them J A Redman of Evesham, Worcestershire, Mrs Hoad of Halstead, Essex, and Dr and Mrs Warrick, from Weymouth, Dorset - think I was too pessimistic about fairy rings on lawns, when I advised Mrs Fotheringham to adopt a pragmatic approach and use nitrogen fertilisers to green up the lawn and thereby "disguise" her ring.

They report that they have had success in eliminating fairy rings by using Armillatox on the soil, after removing the turf. Mrs Hoad said it took her three years to win the battle, which also involved the artful use of a power hose.

Mr Redman says it cost him about £200. So I thought I had better pass this helpful information on to those of you who have a more energetic and optimistic approach to their lawns.

Meanwhile, Mrs Fotheringham has emailed me a sigh of relief and is hoping that the fairies will spirit away her confounded fungus - if they can find it in her newly fertilised, verdant lawn, of course.

Problem pyracantha

Several readers, including R Horsman from Stamford, Lincs, need to know how to prune pyracantha. Some are also worried about brown patchy leaves and unexpected leaf fall.

First the pruning. There is a dilemma: if you cut out old flowering shoots when the blossom has faded to encourage new shoots, you will miss out on all those berries.

The easiest course of action is to prune hard every other year, and accept that you will sacrifice the autumn show. Alternatively, remove about half the shoots bearing old flowers and leave the other half to "berry up".

The patchy leaves of which you complain are the work of the caterpillars of leaf-mining moths that lay their eggs on the leaves in early summer. Despite the resulting leaf damage and defoliation, it is not serious and can be controlled by spraying with a contact insecticide, such as BugClear.

I have noticed that many evergreens that were waterlogged last winter seem to be offloading an unusual amount of old foliage as they start to recover. I have seen a number of unhappy pyracanthas this spring, and I suspect this is the cause.

Happier hedgehogs

Mary Dunkley, of Backwell in Somerset, writes to say that, sadly, she has lost her hedgehog population - because, she is sure, of slug pellets and zealous pest control on nearby farmland. I don't want to open up a can of worms on the subject of wildlife and pest control, but I will mention a tip from a friend, organic gardener Jo Rider, of Cornwall.

It is that, if you must use slug pellets, put them with a few salad leaves in narrow-necked glass jars set on their sides, next to vulnerable plants.

Write to Thorny Problems, Helenyemm1@aol.com or The Daily Telegraph Gardening, 1 Canada Square, London E14 5DT. Helen Yemm regrets that she can answer letters only through this column.

-- Anonymous, July 20, 2001