Invasive plants could be damaging your property
What every homeowner needs to know.
Invasive plants growing in your garden could be causing serious and costly damage to your property without your realising. Some species can undermine foundations, cracking patios and driveways, and spreading rapidly beyond your boundaries, potentially leading to disputes with neighbours.
The financial impact can be significant. Left untreated, these plants can cost hundreds or even thousands of pounds to remove, and in some cases, they can reduce the value of your home or make it harder to sell. Surveyors are trained to spot invasive species, and their presence can raise red flags for buyers and mortgage lenders, particularly in older or character properties.
With many households under financial pressure, early action is essential. While some plants can be managed with simple, low-cost methods, others require specialist treatment, and the longer they are left, the more expensive the solution can become.
As spring arrives, now is the ideal time to check your garden. Many invasive plants appear harmless or even attractive, but ignoring them can lead to long-term structural, legal, and financial consequences.
Propertymark is urging homeowners to act now and has compiled this practical guide to help identify common invasive plants and how to deal with them.
Bamboo
What it is
A fast-growing ornamental plant often used for privacy screening.
Why it’s a problem
Bamboo can spread aggressively underground, pushing into neighbouring gardens and causing disputes. Its roots can also damage patios, paths, and even building structures if left unmanaged.
How to control it
Install a root barrier or dig a trench around 30cm (12 inches) deep
Regularly cut back new shoots
Remove spreading roots early before they establish
New Zealand Pigmyweed (Crassula helmsii)
What it is
An aquatic plant introduced to the UK that rapidly covers ponds and waterways. It flowers in both white and pink shades.
Why it’s a problem
It forms dense mats that block light and oxygen, damaging pond ecosystems and killing other plants and wildlife. It can quickly take over garden ponds.
How to control it
Regularly remove by hand in small ponds
Increase shade to slow growth
Cover with black polythene for at least three months during the growing season
Use herbicides cautiously in winter if necessary
Giant Hogweed
What it is
A large, fast-growing plant with purple-blotched stems and huge leaves.
Why it’s a problem
Its sap causes severe skin burns and long-term sensitivity to sunlight, posing a serious health risk. It also spreads rapidly, crowding out other plants.
How to control it
Always wear protective clothing
Cut the root 10–15cm below ground for small infestations
Use glyphosate in early spring for larger areas or hire specialists
Japanese Knotweed
What it is
An invasive plant with deep, fast-spreading roots.
Why it’s a problem
Japanese Knotweed can cause damage, affecting foundations, walls, and drainage systems. It is also known for reducing property value and complicating sales and there have been legal disputes.
How to control it
Seek specialist advice for effective removal
Excavation may be required in severe cases
Seek specialist advice for effective removal
Himalayan Balsam
What it is
A fast-growing ornamental plant introduced from the Himalayas.
Why it’s a problem
It spreads quickly, forming dense growth that smothers other plants and increases the risk of soil erosion, particularly near waterways.
How to control it
Hand-pull before it seeds
Cut or strim below the first node
Apply glyphosate-based herbicides if needed
Three-cornered garlic
What it is
A bulbous perennial plant also known as three-cornered leek or snowbell.
Why it’s a problem
It spreads rapidly through bulbs and seeds, forming thick patches that crowd out native plants and take over garden beds.
How to control it
Dig up bulbs thoroughly
Apply systemic herbicide in spring
Do not compost – dispose of bulbs in sealed waste
Rhododendron Ponticum
What it is
A dense evergreen shrub introduced as an ornamental plant.
Why it’s a problem
It forms thick growth that blocks light, suppresses other plants, and damages local ecosystems. It can be difficult and costly to remove once established.
How to control it
Cut back and treat stumps with herbicide immediately
Use stem injection for larger plants
Repeat treatment over several years to fully control
Michael Holden, a past president of NAEA Propertymark, and experienced surveyor, said:
“If left untreated, invasive plants can cause significant pounds’ worth of damage to your property. It’s vital that buyers ask whether a property has been affected, and that sellers are upfront about any issues. An experienced and accredited surveyor should help identify invasive plants early and highlight any risks.”
Propertymark advises that if invasive plants are already well established, homeowners should seek a professional assessment to identify the species and recommend the most appropriate course of action.
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