Now, I don't want to be a killjoy about people's pets, but when I see a neighbour's feline stray into my garden, I just want to get my claws out.

I've caught them rolling around in my glorious borders of purple nepeta, otherwise known as catmint (red rag to a bull, I hear you say, but when I planted it years ago, I had no idea it would be such a moggie magnet), using my trees and shrubs as scratching posts and using a variety of areas of the garden to do their business. They've also been known to raid birds' nests.

I don't particularly want to dig my catmint up, but it might be prudent to replant it in a different place so that local cats will disregard other areas of my garden.

To date, the best deterrent I've found was a high-powered water pistol bought from a car boot sale for 50p which I left at the patio door and fired maniacally every time a cat dared to cross my garden path. But here are some other suggestions I've collected over the years...

:: One fellow gardener reckons that the only way to stop neighbours' cats wandering in is to have your own cat (preferably a tom), as this generally keeps other animals out of your garden.

:: Alternatively, try to stop them getting in. Block your boundary gaps with prickly plants or prunings such as holly. Fit wire or string 10-15cm above the top of fences to make it difficult for cats to balance on them.

:: Another solution is an old gamekeeper's trick. Place half-full plastic bottles in borders, as the light reflection off the bottle is supposed to deter animals.

:: Again, mailshot and other unwanted CDs can provide a shining light deterrent when threaded on twine with knots in between to keep them apart. String these across flower beds or hang from trees and the light reflection should deter cats, but maybe not forever.

:: Don't leave exposed soil in borders. Instead, mulch with stone chipping or pebbles, or keep the soil well mulched with a moisture-retaining material such as manure, as wet ground is not particularly attractive to them. Also, invest in a good selection of ground cover plants to deter cats from venturing into your border.

:: Some gardeners swear by putting a couple of drops of decongestant Olbas oil on to used teabags and then scattering them around the area that the cats have chosen to use as a litter tray.

:: If they're scratching your tree trunks, wrap tree guards or fine chicken wire around the base of them.

:: Cover ponds with netting to stop cats diminishing your fish supplies and position bird feeds in a clear area of the garden where they will be inaccessible to cats.

:: Try fitting a squirrel baffle (downward opening cone or biscuit tin) to the posts of bird tables to stop cats climbing up them.

:: There are a number of cat repellents on the market, including sprays and powders, chemical granules and ultrasonic devices whose sensors detect movement and heat and trigger a burst of variable ultrasound said to deter dogs, foxes and cats. But they may not give long-term protection.

:: If cats in your garden are scratching up seedbeds, try putting a galvanised chicken-wire cage over the area and keep it in position until the plants are of a reasonable size.

Whatever method you choose, clear away any evidence of fouling first, as this acts as a magnet for more cats and more fouling. And if all else fails, buy yourself a high-powered water pistol to keep by the back door...

BEST OF THE BUNCH - Cosmos

These cheerful daisy-like blooms on bushy plants add both height and colour to the summer border and are perfect filler plants to replace earlier perennials which have faded. Plant breeders are producing more dwarf versions which are good for patio pots but in mixed borders it's best to go for larger plants which will make more of an impact. Cosmos also provide cut flowers in beautiful colours from soft pinks to carmines and then deep claret-crimson in late summer, which is when the tender perennial C. atrosanguineus, the chocolate-smelling cosmos, comes into flower. They like full sun and moist but well-drained soil. The annuals will thrive with regular top dressing, watering and picking.

GOOD ENOUGH TO EAT - Tackling gooseberry problems

If all the leaves disappear from your gooseberries, they have probably been eaten by the gooseberry sawfly caterpillar, which is often a problem in about the third or fourth year after planting. They initially appear as a cluster of tiny holes in one leaf and then spread out, ruining the whole bush. If you catch them early, you may stop them in their tracks. Do this by shaking the caterpillars down on to a sheet on a dewy morning, then dispose of them. Alternatively, knock them off with a jet of water and spread a thick layer of ash or soot around the stems to stop them returning. Another cause of leaves disappearing is gooseberry leaf spot, which is common in early summer when tiny blackish-brown spots appear on gooseberry leaves which then turn brown and fall early. To deter the fungus, regularly remove the fallen leaves to decrease the chances of the problem recurring next year and spray with a suitable fungicide.

WHAT TO DO THIS WEEK

:: Disbud border carnations for larger blooms.

:: Cut back aubrieta and alyssum in the rock garden after flowering.

:: Complete planting of aquatics if you want a display this season.

:: Take cuttings from perennial wallflowers and verbascum hybrids, penstemons and diascias.

:: Thin peaches for the remaining fruit to reach a good size.

:: Trim and train outdoor vines.

:: Move desert cacti outdoors to a sunny patio or sheltered corner for the summer.

:: In dry weather, leave grass clippings on the lawn to help retain moisture.

:: Layer the low-growing branches of chaenomeles, cotinus and magnolia.

:: Continue to give early potatoes a good soaking once a week to ensure good yields.

:: Stop cutting established asparagus.