Horse Chestnut Tree (Aesculus hippocastanum)

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Dutch Elm Disease wiped out millions of UK elms back in the 70’s and now the latest news from environmental experts is telling us that the horse chestnut (conker tree) could be next and within 15 years they could disappear from our landscape. The leaf miner moth lays its larvae on the leaves of the horse chestnut tree causing premature leaf drop. Older trees that can fight it are then susceptible to bleeding canker disease.

Native to the Balkans, horse chestnuts were first imported to England in the 1600’s. They are rarely found in woodland, but are a common site in parks and gardens. A mature horse chestnut can grow to around 40m and can live for up to 300 years. It has beautiful large palmate leaves, Flowers that appear in May and fruits which once pollinated develop into the conkers that we all love to look for in the autumn once they’ve fallen.

When the leaves fall from the tree, the leaf stalk leaves a scar on the twig in the shape of an inverted horse shoe with nail holes. It could be that this association with horses led to people feeding them ground up horse chestnuts thought to relieve them of coughs and thereby giving the horse chestnut its name.

In Germany horse chestnuts are often found in beer gardens as before modern refrigeration brewers would dig cellars under them. The large canopy and shallow roots were perfect to protect the cellars from the summer heat and the practise of serving beer at these sites evolved into the modern beer garden.

During the first world war, there was a government campaign for people to collect conkers and hand them in to be used as a source of starch. The starch was fermented to produce acetone which was used as a solvent to produce cordite which was used in military armaments. The government chose to use conkers to avoid starvation of the population by depleting food sources. They were a poor source of starch, but were collected again in world war two for the same reason.

Nowadays, horse chestnuts are enjoyed by adults and children everywhere for use in the game of conkers. The world conker championships have been held every year in Northamptonshire since 1965. This year for the first time they struggled to get enough conkers for the tournament due to so many being infected by disease.

Sadly, the disease is so widespread that there’s now not much we can do to control it. The key thing is to encourage good woodland management and tree care to ensure maximum tree health.

If you are concerned about the health of trees in your ownership and need help diagnosing symptoms, please do contact us We provide a tree health assessment service to our clients, which can cover a few trees or a large area of woodland. This service involves diagnosing causes of ill health in trees, and providing practical management solutions to these problems.

Observatree is a project about establishing a tree health early warning system. It is encouraging more eyes on the ground and for everyone to not only look out for pests and diseases in trees, but also to report them. To find out more about the project and how to identify and report your findings go to

Tree of the Month: October’16