Buddleia - a risk to property and developers

This is a plant that can grow from tiny cracks in walls, roofs, bridges and hard surfaces, even chimneys. Buddleia develops an extensive root system capable of widening existing defects and accelerating structural deterioration. It is increasingly found on residential properties, commercial buildings, industrial estates, railway infrastructure and development sites across the UK. 

What is Buddleia?

Buddleia (Buddleja davidii) is a fast-growing deciduous shrub originally introduced to the UK as an ornamental garden plant. Its ability to thrive in poor soils and colonise disturbed ground has allowed it to spread rapidly into urban environments.

It is particularly common on railway embankments, brownfield land, vacant buildings and construction sites. Its lightweight seeds are dispersed by wind, allowing new plants to establish almost anywhere. 

Why is Buddleia a problem?

One of the most common questions we hear is: “Can Buddleia damage buildings?” The answer is yes. Buddleia rarely creates structural damage in sound construction on its own, but it readily exploits existing weaknesses such as cracked mortar, defective brickwork, joints and weathered masonry. As the roots and stems enlarge, they can widen those defects and accelerate deterioration.

Potential impacts include:

• Damaged brickwork

• Cracked masonry

• Loose stonework

• Deteriorating retaining walls

• Lifted paving

• Blocked gutters

• Roof damage

• Water ingress

• Increased maintenance costs

Older buildings are particularly vulnerable because of weathered mortar and ageing construction materials. 

Can Buddleia damage foundations?

In most situations, Buddleia does not directly penetrate or crack intact concrete foundations. However, its vigorous root system can exploit existing defects in foundations and this can lead to deterioration of structures built on the foundations, causing weakened masonry, retaining walls and other shallow structures.

For developers and surveyors, the greater concern is often the plant’s ability to establish itself within inaccessible parts of buildings and infrastructure, making future maintenance more complex. 

Why is Buddleia a problem on construction sites?

Developers regularly encounter Buddleia on land planned for construction. Although Buddleia is not regulated like Japanese knotweed, it can still present significant challenges during site preparation, and if not dealt with prior to the build, it will cause problems later on in the project and worst case scenario – for the property owners.

Challenges include:

• Restricted access for demolition

• Damage to retaining walls

• Vegetation clearance requirements

• Increased health and safety risks

• Programme delays

• Additional enabling works

• Increased maintenance liabilities

Removing Buddleia before construction begins allows contractors to work more safely and efficiently. 

How does Buddleia cause damage?

Jennifer Holmes from Environment Controls explains: "Unlike many ornamental shrubs, Buddleia is extremely opportunistic. Seeds germinate in tiny pockets of accumulated dust and organic material. As the plant matures, its roots expand into existing cracks while the woody stems increase in diameter. This combination can force apart loose masonry, accelerate frost damage and increase water penetration. It can also destabilise neglected walls and cause blockages to infrastructure and drains. Without management, small plants can quickly become large shrubs several metres tall." 

Buddleia on residential properties

For homeowners, Buddleia is often first noticed growing behind sheds or outbuildings, along fences, on garages or walls and in gutters. Ignoring the plant rarely solves the problem, and as seeds will grow pretty much anywhere, even your roof isn’t risk free. 

Professional Buddleia removal vs DIY

Many people search for DIY options and ask if Buddleia can be killed by cutting it down. But simply cutting the shrub to ground level rarely provides a permanent solution because regrowth commonly occurs from the remaining root system. Professional control usually involves chemical treatment or digging it up. 

Herbicide Treatment: Ideal where long-term control is appropriate. Benefits include minimal disturbance to your property or site, reduced regrowth, suitable for inaccessible areas and cost-effective management. 

Mechanical Removal: Where immediate removal is required, excavation or mechanical removal may be recommended, particularly before construction or major landscaping. 

So in a nutshell - Buddleia if controlled is a beautiful plant, loved by insects and butterflies, but can turn nasty if left alone. To avoid risk of damage to property structures, or development sites, it's best to consult a specialist Buddleia removal contractor.

This article was written by Environment Controls