Four 'invasive' plants that are deemed 'illegal' if they spread from your garden

Hefty fines and a prison sentence could be on the cards if you let four of these plants grow unruly.

It's that time of year again, when green-fingered fanatics will be weeding, pruning and planting flowers to get their gardens 'summer ready'. And while many will be keen to see their greenery flourish, pesky invasive plants may also be in their midst.

Believe it or not, you could face hefty fines and even jailtime if you're not quick to stop certain alien species from growing out of control. These can become an utter nightmare for wildlife - often brutally smothering other plants to make even more room for themselves.

So, keeping an eye out for the common ones is not only healthy for the garden, but your bank account too. It's vital to take a good look around your property this spring, ensuring these alarming four are not hiding in plain sight.

American skunk cabbage

Skunk cabbage in the sun

Don't be fooled - this leathery plant isn't the kind of cabbage you may hope to get with your roast dinner. In fact, chewing it at all can burn your mouth, irritate your kidneys and even cause death - so, definitely not recommended.

But aside from that, intentionally growing American skunk cabbage is completely banned in the UK and letting it spread beyond your land could be an offence. Depending on its severity, this could range between anything from a warning to two years in prison, with the Government eager to crack down on its growth.

The reason for this is largely due to its giant, dense leaves which cast shade over other plants and limit their access to vital sunlight, threatening their survival.

These plants arrived first arrived to the UK in 1901, after someone from the US brought one over to keep as decoration. Now, you'll find them all across British woodland and waterways, with their roots thriving in boggy soil conditions.

To spot them for yourself, watch out for their distinctive yellow leaves and pungent aroma. If you hadn't guessed already, this smells a bit like a skunk's rotten egg stench - so, you'll certainly be wanting to banish them before any summer BBQs.

Chemical pest control is ideal for putting a halt to their growth, and gardeners should then burn the plant material or dispose of it responsibly.

Japanese Knotweed

Japanese Knotweed

Japanese Knotweed is a notoriously invasive species that's enough to give any homeowner the chills. Not only is it quick to spread relentlessly across a garden, but it's also known to wreak unbelievable havoc on buildings.

While the plant often seems small, its roots can extend to a staggering two metres in a quest to find water. In doing so, it will force its way through paving slabs, sewers and even concrete, which can cause infrastructural damage in the long term.

Samantha Towle, director at JMP Solicitors, previously told The Mirror: "The law is very clear – if you have Japanese Knotweed on your property, you must not allow it to spread onto neighbouring properties. It would be classed as a private nuisance and you could be prosecuted under civil law resulting in financial penalties."

To stop Japanese Knotweed in its tracks, Property Mark also recommends watching out for reddish, asparagus-looking roots that may crop up in the soil. These will soon turn into green bamboo-esque stems, with the ability to flourish at a rapid rate.

Using the right herbicides and physical extraction can help to rid of these pesky plants, though expert attention is recommended in severe cases.

Giant hogweed

, Giant hogweed

At first glance, this weed may look quite similar to cow parsley, thanks to its bristles and jagged leaves. But this enormous plant is nothing of the sort and should be treated with the utmost care.

Originally from Russia and Georgia, Giant hogweed is known for its toxicity, with the chemical in its sap causing significant blistering and long-lasting scars to anyone who touches it. And, like the American skunk cabbage, its leaves also pose a huge shade problem for other plants - once again threatening their survival.

Disposing of this beast is no mean feat however, and should only be sent to specific licensed landfills with the required documentation, according to the Royal Horticultural Society (RHS). Seeking expert advice is also recommended to anyone concerned about the risk of cutting it, though it can be burned or slashed down with the right equipment.

Regardless, the Government states that it should not be imported or purposely bred, unless you have a specific exemption to do so.

Himalayan balsam

Closeup of the plant with leaves and flowers

While the Himalyan balsam is rather beautiful, it should not be underestimated. This towering pink plant is another that can unleash destruction in your garden by ruthlessly smothering plants as it grows higher and higher.

Staggeringly, the RHS also claims that each plant can release around 800 seeds which spread over a distance of 22ft. So, putting a stop to its growth early is vital for keeping a major problem at bay.

Once again, weed killer can be used to combat this, though pulling the plants out before they flower and set seed is preferable to prevent any harm to other species. "Conservation authorities regularly organise 'balsam bashing' work parties to clear the weed from marshland and riverbanks," the RHS says.

"Hoe off seedlings. Dig or fork out plants."

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