Why Councils Are Banning Thuja Hedges and What Homeowners Can Do

Anyone heading to the planning department today with plans for a tall, opaque hedge along the boundary is increasingly being told a flat no. One plant in particular has moved into councils’ sights: thuja, the long‑time default in new-build estates. Local authorities are now deliberately ruling it out, citing fire risk, a poor environmental footprint and declining, disease-hit stands.

How councils restrict Thuja hedges through planning rules

There is no nationwide law that bans thuja across the board. Instead, councils use other levers: local development plans, zoning and landscaping requirements, and the detailed rules attached to building and planting.

These documents can spell out exactly which trees and shrubs are permitted along roadsides, on plot boundaries or in new developments - and which are not. In many places, thuja hedges now appear explicitly on lists of prohibited species, typically alongside other uniform conifers.

Anyone who plants a newly prohibited thuja hedge anyway risks committing a regulatory offence, being ordered to remove it, and receiving a fine of up to €1,500.

In day-to-day practice, departments often take a fairly pragmatic approach:

• Checks focus mainly on new builds and newly submitted garden or landscaping plans.
• Existing older hedges are often tolerated until they become diseased or develop gaps.
• Some councils offer financial support or free advice to help residents switch to more nature-friendly hedging.

If you are unsure, it is worth making a quick phone call to the planning office or the parks and green spaces team before you plant. Reading the local by-law or guidance can prevent expensive surprises later.

Why a former garden favourite has become a problem

Ecologically, almost a dead zone

For years, thuja seemed perfect: evergreen, quick to form a screen, low maintenance and inexpensive. From an ecological perspective, the outcome is sobering. Conservation groups now describe it as "green concrete" - and there is a very specific reason behind that label.

Its scale-like leaves contain compounds that, as they rot down, make the soil markedly more acidic. The pH can drop to below 5. Many soil organisms, fungi and bacteria disappear, and earthworms become scarce. In the worst cases, what remains is an almost sterile strip of ground where hardly anything else will grow.

Where a mixed hedge can support dozens of animal species, a single-species conifer hedge offers food and shelter to very few. Specialists cite figures that are hard to ignore:

• up to 35 small-mammal species around diverse hedges
• around 8 bat species
• in some cases more than 100 insect species
• up to 80 bird species using them to rest or breed

At the same time, populations of many native bird species are falling. In densely built-up residential areas, every feature that provides food and nesting sites matters - and a sterile wall of conifers does little to help.

Fire risk right between homes

Fire safety is at least as serious an issue. Thuja contains essential oils that concentrate strongly in hot, dry weather. During prolonged dry spells, a single spark - from a fire pit, a discarded cigarette or an electrical fault - can be enough for the hedge to ignite quite literally.

Tests show that a dried-out thuja hedge can flash over within seconds and reach temperatures well above 800 degrees.

In tightly packed neighbourhoods, such a hedge can act like a fuse between garages, carports and homes. Fire crews have been reporting for years on front gardens where a single hedge fire has damaged multiple house façades.

On top of that, the biggest wave of thuja planting dates back to the 1970s and 1980s. Many plants are now old, past their best and affected by fungal diseases such as Coryneum. Dry, brown sections further increase the risk - and also make the hedges look unattractive.

What to do if your Thuja hedge is affected

If the local rules state that no new thuja hedges are permitted, that initially applies only to new planting. It becomes tricky when an older hedge is so badly damaged that it needs replacing - or when the council contacts you directly.

In those situations, many authorities recommend a complete switch to a "hedge of native shrubs". It takes a little more effort, but it pays off over time for soil health, wildlife and fire safety.

Removing an old Thuja hedge properly

Gardeners usually advise removing the root stumps mechanically - using a digger, a spade or a stump grinder. The soil beneath is often heavily acidified and depleted. Before any new planting goes in, it needs a proper recovery period.

• Work in around 50 litres of mature compost per metre of hedge.
• Add a little ground limestone (calcium carbonate) or similar products to raise the pH.
• Loosen thoroughly and, if possible, leave it to rest for a few weeks.

Important: do not simply shred the old branches and use them as mulch under new shrubs. The resins and terpenes they contain inhibit germination and suppress soil life.

It is better to dispose of thuja cuttings via the local recycling centre, or compost only small quantities long-term, mixed with plenty of nitrogen-rich material such as grass clippings.

Suitable alternatives for a living hedge

Many councils and conservation advisers recommend mixed hedges made from native shrubs. They bring flowers, fruit and seasonal change into the garden - and they offer wildlife a real buffet.

Commonly suggested combinations include:

• hornbeam for the main structure and fast, dense coverage
• dog rose or other wild roses for flowers and hips
• hawthorn or blackthorn as bird food plants
• hazel for early blossom and nuts
• alder buckthorn or Cornelian cherry as food for insects and birds

At least four different woody species along a single hedge line are recommended. That creates a robust, resilient structure. Many regions and councils provide grants - sometimes a few euros per shrub - when native species are planted and documented.

How to combine privacy screening and nature conservation

A common objection is: "I need a dense privacy screen, otherwise everyone can see into my garden." That can be achieved without a sterile conifer wall. With a little patience and smart planning, you can have a hedge that becomes almost as closed within a few years - but far more alive.

A few practical tips:

• Plant in a fan shape: lower shrubs at the front, taller ones behind.
• Plant a little more densely at first, then remove individual plants later as they mature.
• Avoid clipping it "like a ruler" every year; shape it lightly and thin it more firmly every few years.
• Schedule major cuts for the leafless period, roughly November to December.

This leaves enough berries and buds for birds, and the hedge becomes increasingly attractive to wildlife over time. If you want it particularly opaque, combine shrubs with climbers such as clematis or native honeysuckle.

Why switching pays off in the long run

At first glance, being forced to move away from the familiar thuja strip can feel like unnecessary hassle. Yet in many gardens, a different picture emerges after a few years: the new hedge becomes a lively focal point of the plot. More birds, more butterflies, more blossom - and a better feeling during droughts and heatwaves.

If you need to replace your existing hedge anyway, or you are building new, it is wise to take councils’ signals seriously. A varied hedge of native species is not only usually trouble-free in regulatory terms; it is also more resistant to disease, holds more water in the soil, and heats up less than a dark wall of conifers.

With increasingly dry summers and rising fire risk, planting around the home is becoming a safety issue. With good planning, you can get privacy, a richer nature experience and a better garden microclimate - and avoid conflict with the council and neighbours.