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What Are The Most Destructive Garden Plants In The UK

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  • 20-04-2022
What Are The Most Destructive Garden Plants In The UK

What Are The Most Destructive Garden Plants In The UK? This article looks at various invasive plants including Japanese Knotweed, Giant Hogweed, Himalayan Balsam, New Zealand Pygmyweed and Rhododendron Ponticum.

Most Destructive Garden Plants In The UK

You may think that invasive plants are just an annoyance, but they're so much more than that. These types of plants can cause structural damage to your home. If your home suffers from structural damage, its value can decrease significantly. 

It can also harm native species of wildlife in your garden, like worms, frogs and bees. When people think of these types of invasive species of plants, they think of places like a jungle or rainforest, but there are a few destructive plants in the UK.

There are some serious issues with these types of incredibly invasive plants, such as being capable of destroying an entire habitat if the problem is left untreated. 

How Do Invasive Plants Invade A Garden?

The most invasive plants have a few culprits, the top ones are Japanese knotweed, giant hogweed, Himalayan balsam, New Zealand pygmyweed and Rhododendron ponticum. Just remember, if you have an issue with this kind of thing, you should always consult with a professional.

Japanese knotweed

Japanese knotweed is one of the worst invasive weeds in your garden. 

The plant can only spread using its roots because it doesn't produce seeds, but the roots grow to an extensive amount and are very strong and durable.

The best thing you can do is to dig the weed out as it's the most environmentally-friendly thing to do.

The issue with this process, however, is that even if a tiny bit of root is left, it can produce an entirely new plant.

A method of preventing this from happening is using chemical sprays that you apply to the leaves, which the entire plant absorbs; even still, it can take a few years to kill this weed.

What Are The Most Destructive Garden Plants In The UK

Did you know that Japanese knotweed can grow up to 10cm in a single day? There have been times when buyers of a house would pull out of the deal because of the discovery of Japanese knotweed on the property. 

It can also affect people trying to get a mortgage too. It's also illegal to grow Japanese knotweed because of the 1981 Wildlife and Countryside Act. If the person who has this plant on their property isn't controlling it, a community protection notice will be given. 

Giant hogweed

Giant Hogweed - Destructive Garden Plants In The UK

This plant had originated in Southern Russia and Georgia, and it this one of the most dangerous plants on the list.

Giant hogweed can grow over three metres in height; alongside that, giant hogweed has a toxic sap that causes some horrible skin burns.

Originally people had giant hogweed as a decorative plant, but it got loose, and all they did was end up introducing new plants and pitting them against our native plants.

There is no obligation for landowners to get rid of giant hogweed off their property, but it is still an offence to let it grow, and the local authorities will usually take action against hogweed and remove the infestations from public areas.

If you intend on removing this plant from your property, you should take care and be sure to always wear gloves, a facemask, and to cover your arms and legs. You don't want the nasty sap to make contact with you as it can burn human skin.

Himalayan balsam

Himalayan balsam can be easily identified by its beautiful display of pink flowers that it produces.

Despite this, though, Himalayan balsam can be incredibly tricky to control once it gains a hold on your garden.

Himalayan balsam can grow way above head height, around 2-3m in height.

The reason it can be so hard to control is due to the fact it produces a huge number of seeds per year, 800 of them.

Each of these tiny seeds can survive up to two years, alongside that, the plant itself can actually survive without much sun, so it can thrive in shady areas.

Himalayan Balsam - Destructive Garden Plants In The UK

Originally from the Himalayas, it was introduced into the UK in 1893, where it became an incredibly invasive weed on the riverbanks and ditches. The reason this plant is such a huge problem is that it grows over other native plants and shades them out, which over time destroys habitats as shading over vegetation kills other plants.

New Zealand Pygmyweed

New Zealand Pygmyweed - Destructive Garden Plants In The UK

New Zealand pygmyweed is an aquatic plant that grows primarily in water or in soil that contains a heavy water content, usually by lakes and rivers.

The plant was first introduced into the UK from Tasmania in 1911, although it wasn't recorded in the wild until 1956.

Also known as Australian swamp stonecrop,  New Zealand pygmyweed is extremely invasive and is a difficult task to control.

One of the core problems with New Zealand pygmyweed is that it creates dense matting, which is usually on the surface of ponds, and this can decrease the oxygen levels available to any fish and frogs.

In turn, this makes the pond essentially uninhabitable. New Zealand pygmyweed has already wiped out many locally native plants in the Lake District. It's hard to control as it has no natural predators.

Rhododendron ponticum

You can identify this plant by its big purple flowers, it may look beautiful, but it's a very invasive species of plant.

Rhododendron ponticum spreads rapidly, which causes massive damage to native woodlands, meadows and heaths.

The main issue with this plant is that it grows into massive bushes, which block out the sunlight and smother other wild plants and trees.

Its leaves are also toxic to the native animals, which means it has no natural predators.

These leaves repel the native wildlife like the earthworms and birds in the area.

Rhododendron Ponticum - Destructive Garden Plants In The UK

Each of the plants produces one million, and sometimes more, tiny seeds every year, which spread using the wind. The plant is extremely hard to get rid of by just digging it up or using any herbicides.  

How Does UK Law Cover Invasive Plants?

There are different laws considering different plants. Some are more invasive than others and can cause more damage, which costs more money. 

For example, Japanese knotweed is estimated to cost the UK economy around £166m per year. Japanese knotweed is also illegal to allow it to spread. Meaning if you have it on your property, you must remove it.

Giant hogweed is also illegal to plant, and it is against the law to allow it to grow. The case is the same with Himalayan balsam. New Zealand pygmyweed is now illegal to see in the UK; this is one of five water plants you are no longer allowed to sell. Rhododendron ponticum is also illegal to plant or allow the growth of. 

Although the plants on this list are illegal, there are other plants that are illegal to grow or allow the growth of. There are also other invasive plants that aren't illegal to grow, such as green alkanet.

Do you have a Japanese Knotweed problem? If you require Japanese Knotweed Removal in Essex or throughout the UK, contact our expert today.