Disease-resistant elms planted to boost butterfly and tree conservation

Over the last 50 years, millions of elm trees across the UK have succumbed to Dutch Elm Disease. But on The Hadlow Estate an ambitious project is helping to reclaim this tree for generations to come.

Elm trees have not only shaped rural England but have also provided an important economic resource, with elm wood used to build ships, furniture, coffins, and more regionally, the structural cone of oast cowls.

But in the late 1960s Dutch Elm Disease (DED) took hold, resulting in the loss of over 90% of the UK’s elm population, an estimated 25 million trees – and the Estate was not spared.

So earlier this year when Forester, Rick Vallis, prepared and planted 30 young elm trees, specifically bred to be resistant to the destructive disease, it marked a pivotal moment for The Hadlow Estate’s elms and wildlife.

Heritage & Hairstreaks

The decline of elm trees over the years has had big consequences for White-letter Hairstreak and Large Tortoiseshell butterflies – two rare species reliant on mature, flowering-age elms for caterpillar food and breeding habitat.

“White-letter Hairstreaks only have a small dispersal range, only travelling about 1km to find new habitat.” says Dr Roland Brown, Chair of Butterfly Conservation’s Kent and South East London branch.

“This makes them very vulnerable to becoming isolated and if their local elms are wiped out by disease – or growing climate pressures like drought – their chance of survival is very slim.”

But there is hope on the horizon, and by participating in the Elm Heritage Kent project, as part of its broad conservation efforts, the Estate is working to reclaim its lost elms and create much-needed habitat corridors, linking up other butterfly habitats on the wider Estate.

Elm Heritage Kent Project

Elm Heritage Kent is a project of Kent County Council’s tree-planting initiative, Kent Plan Tree, which in four years has planted over 94,000 native-species trees.

In 2024, the project partnered with the Kent & SE London Branch of Butterfly Conservation and Natural England’s East Kent Downs Farmer Group, to identify areas with existing records of White-letter Hairstreak butterflies and elm trees.

Project officer, Katherine Meade says: “Using this data, we were able to strategically plant more DED-resistant cultivars, benefiting existing butterfly populations by creating corridors and stepping stones of elm habitat between existing mature tree locations.”

Last winter, the Estate became involved in the project when two locations were identified for strategic planting. Close to Tudeley Woods, one area is a 200-250 metre section of mature hedgerow, and the other is an area around a nearby pond.

Planting the Estate

In early 2025, Rick and a forestry colleague prepared these areas for the first DED-resistant cultivars – varieties specifically bred for traits like disease resistance – on the Estate.

The cultivar ‘Lutece’ was supplied through the project as three standards (2m tall trees) and 27 feathers (two-to three-year-old saplings).

Rick fitted rings of six-foot-high mesh around the standards, and tree guards to protect the feathers from browsing wildlife like deer.

Watering is also very important and through the hottest and driest weeks, Rick has used up to 10 litres of water per tree per week.

For the first three to five years, the elms will require higher levels of attention, including weed control, and pruning to ensure as many as possible are successful in establishment – failed trees will be replaced. Once established, tree protection will be removed and they will be annually managed, as part of the Estate’s wider forestry operation.

Record, record, record

Kate Teacher, of The Hadlow Estate, says: “We’re pleased to be part of Elm Heritage Kent – a great project to restore elms to the countryside.

“We will be monitoring our new elms over the coming years and look forward to sharing updates as they begin to establish themselves as habitat for the Estate’s beautiful White-letter Hairstreak butterflies.”

Katherine adds: “Local people and enthusiasts collecting elm tree and butterfly data really helps to inform us of good DED-resistant elm planting sites. Records are also used to track the growth and impact of connected elm tree habitats across the county.

“We encourage people to learn more about elm and butterfly identification and contribute to our records – it really makes a difference.”

• Upload Elm records to (UK Records) iRecord 
• Upload White-Letter Hairstreak to iRecord Butterflies

Take a look at more pictures of the DED-resistant elm tree planting…