Once upon a time, the worst that could happen to your garden was that someone might dig up a few of your prize daffodils. Times, though, have changed, and today’s green-fingered thieves go equipped with devices a lot more sophisticated than just a small trowel and crossed fingers. They think nothing of removing hanging baskets by the lorryload.

Recently, an organised gang was suspected of stealing wisteria from gardens in Hampstead, north London. Plus, if a sculpture or stone statue is too heavy to move by hand, they won’t hesitate to bring in a bulldozer or small crane. They wait until you are away, and tell any inquiring neighbours that you have decided to get rid of your solid brass Venus de Milo, or collection of gnomes.

Hanging baskets are easy targets Credit: Features Scan

One home owner, for example, woke to find that both his 6ft bay trees, which cost £200 each, and took two burly men to install, had been removed in the night. Another unfortunate couple came back from holiday to find both their greenhouse and roses had been removed. According to crime statistics, each year, one in seven homes has something stolen from their garden. After all, even a modest home owner can typically have £5,000 of goods out on display: shrubs (£1,200), table and chairs (£2,000), barbecue (£300), granite bench (£400) and assorted fancy fish plus water features (£1,100).

A recent Home Office study found that thieves are actually more likely to steal garden furniture, including gnomes (9.6 per cent of thefts) than credit or debit cards (8.2 per cent). On the basis that a plastic figure is less likely to, well, grass you up. Unless, of course, you take the trouble to write your postcode on his underside in indelible ink. But even if you’ve already thought of that, it’s a constant battle to keep ahead of the crooks.

Today, professional garden thieves will often write over the top of your address with their own marker pen. The best way to counter this is to daub your property with a clear liquid called SmartWater. Each phial of SmartWater has its own unique chemical DNA, which the police distribute free of charge in certain high-risk areas. Once applied, the criminals can’t obliterate it; so if just one speck is left, it can be sent off to a central database to establish rightful owner. Of course, no garden thief wants to walk the streets carrying the tools of his trade. Instead, they rely on home owners to leave their shed unlocked, thus providing access to spades, forks, ladders and other handy aids.

Something as cumbersome as a bay tree isn't always safe either Credit: Alamy

But can thieves really be bothered to break into your shed? You bet they can. In 2014, there were 3,000 shed burglaries in Warwickshire alone. As well as keeping our sheds as secure as possible, it’s a good idea to chain all tools together with a bicycle padlock – preferably one that’s combination-operated so you don’t have to keep fetching the key.

According to rough estimates, some £4 billion of garden furniture, plants, paving stones and wildlife are stolen each year in Britain. You only have to type in the words “garden crime” into your computer, and you come up with heartbreaking stories of expensive and much-loved statues being uprooted and removed. Such as the 45kg stone wizard, spirited away from a house in Lindfield, Sussex.

Or the 150-year-old sandstone sundial that was reported stolen from a garden only six weeks after the owner had died. Or the 5ft 7in fairy statue, which was wrenched from the soil in Ipswich, despite having been cemented into the ground. Visit theft-alerts.com and the list of statues spirited away makes for depressing reading. So determined are these modern-day, Wellington-ed wrongdoers, that they will even target expensive paving slabs, made out of York stone.

Garden statues are often targeted Credit: Alamy

Householders tell of waking up to find a mud path where there used to be a solid walkway. However, home owners have to resist the temptation to install low-level explosives or tripwires, and we must stop short of using deterrents like razor wire or broken glass. Putting these on top of gates or fences can land the home owner in trouble if injury is caused to the person breaking in.

A wounded intruder can haul you up in court to face prosecution. In which case, you will be the person facing a fine or imprisonment. Of course, it’s never a good idea to challenge an intruder in your house, when you are dressed in just your pyjamas. Increasingly, these days, people are resisting the urge to have-a-go. Instead, they install closed-circuit TV, in order to film wrongdoers in the act of removing their prized petunias or statue of Peter Pan. A cheaper alternative is to use hardened rubber spikes, such as Prikka-Strip, which are both legal and effective.

The other thing statue-snitchers don’t like, of course, is being spotlit mid-theft. According to guidelines issued by the police initiative Secured by Design, the most effective form of security is low-energy lighting. This is controlled by a “dusk-to-dawn” switch which is operated by sensors and comes on only when it’s dark. These are best fitted at a height out of the average criminal’s reach, at least 8ft above ground.

Alternatively, if you have a tree or shrub that is worth hundreds, or thousands of pounds, you can invest in an automatic alarm that wakes you (and the neighbours) should anyone try to remove the plant container. Mind you, losing the odd yucca is not as distressing as losing the world’s smallest water lily (Nymphaea thermarum, smaller than a pound coin, extinct in the wild). It was removed last year from the Princess of Wales Conservatory, at Royal Botanic Gardens Kew. And Kew is not the only public garden that has felt the rough imprint of the felon’s spade.

Snowdrop bulbs aren't safe either Credit: Christopher Jones

Last year, the Sir Harold Hillier Gardens in Hampshire had so many rare snowdrops stolen (street value £100 a time), that they now only keep them on limited display. The fact is, plant crime is big business: while there are just 5,000 animals on the endangered list prepared by the Convention of International Trade in Endangered Species (CITES), there are 30,000 plants registered as being at risk.

Which means that an unscrupulous plant-snitcher could get £1,000 for a South African cycad (some are 200 years old), and as much as £5,000 for a rare lady’s-slipper orchid. Not bad for a night’s work, and a lot less risky than having to force entry into someone’s home, and risk being confronted by an angry householder. That said, some institutions are waking up to the possibility of sneak thieves coming and helping themselves under cover of darkness.

Try and dig up a snowdrop bulb at Anglesey Abbey, in Cambridgeshire, and you’ll find it almost impossible to sell (£725 the going rate), because it has been security tagged. One-nil to the upholders of horticultural rectitude.

Ten ways to foil the burglar in your garden