Invasive plants are not just an irritating nuisance for gardeners, but you could be breaking the law if you are planting or letting some of them spread out of your garden. These plants tend to be incredibly difficult to control and do not have to be weeds, as many non-native invasive plants can be beautiful flowers, which can mean many gardeners may not know what they have growing in their garden.

The experts at GardeningExpress noted that offenders found "planting or allowing the spread of these banned species could face fines of up to £5,000 or even a prison sentence of up to two years". They have shared three plants that are listed in Schedule 9 of the UK's Wildlife and Countryside Act - these plants are known for their aggressive growth and spread, potentially harming people, infrastructure, and the environment. While not regulated, three other plants are not regulated but need constant attention.

Chris Bonnett, founder of GardeningExpress, said: "Managing invasive plants in your garden requires understanding which species pose risks and how to control them. It can be illegal to plant or cause the spread of plants which are listed under Schedule 9 of the UK's Wildlife and Countryside Act."

Himalayan balsam

Himalayan balsam is a tall plant with explosive seeds that can float on water; this gives them the ability to spread and grow quickly across the country. This non-native species also outcompetes other native plants for nutrients, sunlight and space, which can disrupt ecosystems.

Although it isn't illegal, it is recommended to either control or get rid of Himalayan balsam to prevent it from spreading. Remove by pulling it up in autumn and winter when there are no seeds to prevent them from popping into other areas of the ground.

Giant hogweed

Native to the Caucasus Mountains and Central Asia, giant hogweed can grow up to five metres tall and should not be intentionally planted in the UK.

Giant hogweed has sap which can cause sunlight to burn your skin and blister. This is from a substance it contains called furocoumarin, which makes the skin extremely sensitive.

To remove this invasive species, call in a professional or wear full protective clothing to prevent sap from coming in contact with the skin if removing it yourself.

Japanese knotweed

Japanese knotweed is also not native to the UK and is considered an "illegal plant to grow". It can overcrowd other native species by spreading rapidly through its underground stems called rhizomes.

This plant can grow 10cm a day, with the strength to grow through concrete and asphalt, and it can take three years to completely eradicate.

English ivy

Moving onto the non-regulated plants, English ivy is an evergreen climber which can grow fast, smothering anything from buildings to other plants.

If ivy covers plants, it can cause them damage by reducing their access to sunlight and nutrients. Express.co.uk have shared the easiest way to remove ivy for good that's approved by a gardening expert.

Bamboo

Bamboo is one of the fastest-growing plants in the world, and it can be greatly invasive if not contained in pots and planters.

Underground rhizomes can cause the plant to grow beyond where it has originally been planted, spreading into neighbouring gardens and even causing damage to buildings.

Butterfly bush

Butterfly bush is non-native and can overtake native plant species, whilst attracting pollinators, which deprives native plants of pollination. Butterfly bush spreads quickly through its high seed production and is often found in derelict areas, where the seeds grow from cracks.

This bush can damage infrastructure from its strong root system, and if removed, must be either burnt or bagged up to prevent seeds from spreading dangerously.