Horse Chestnut

Horse chestnut; tree that can grow over twenty-five feet tall with a broad crown.

Do not confuse with:
Sweet chestnut (Castanea sativa)

Also known as:

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recognize Horse chestnut
Horse chestnut, photo Toubib - CC BY-SA 3.0
  • Chestnuts are eaten by wild boar, deer, pigs and cattle; to humans and dogs the chestnut is slightly poisonous.
    The chestnuts of the sweet chestnut (entirely different plant: Castanea sativa) are edible, however.

Horse chestnut(Aesculus hippocastanum), tree that can grow over twenty-five feet tall with a broad crown. The horse chestnut is a tree of the Northern Hemisphere.
The white horse chestnut (Aesculus hippocastanum) is most common; the red horse chestnut (Aesculus ×carnea) is seen less frequently. The red variety also remains a bit lower in height, but still a respectable 20 meters.


recognize damage Horse chestnut leaf miner
Brown spots in the leaf, photo Georg Slickers – CC BY-SA 3.0

Mesophyl is eaten from the leaf, causing brown spots; the leaf turns to brown and dies: Horse chestnut leaf miner (Cameraria ohridella).

recognizing horse chestnut scale
Horse chestnut scale on maple tree, photo: Cwmhiraeth – CC BY-SA 4.0

Brownish aphids populate the stem: Horse chestnut scale (Pulvinaria regalis).

Fungi & diseases

recognize Horse chestnut bleeding canker
Bleeding spots on the trunk, photo: Rasbak – CC By-SA 3.0

Moist, brown spots develop on the bark of the trunk that secrete a viscous fluid: Horse chestnut bleeding canker.

The leaves wilt suddenly because the sap flow is disrupted. Eventually, the trees die: wilt (Verticillium spp).

Recognize coral spot (Nectria cinnabarina)
Coral spot, photo: Pethan – CC BY-SA 3.0

Small, orange-red mushrooms appear on affected branches, which can be either dead or living branches: Coral spot (Nectria cinnabarina).

recognise giant polypore
Top view of older giant polypore, photo: Henk Monster – CC BY-SA 3.0

Between 50 and 200 cm tall fungi with several flat, semicircular caps at the base of the tree. Initially light brown; later darker in color (reddish brown): giant polypore (Meripilus giganteus).


A chestnut only flowers after about fifteen years. Under poor growing conditions, the tree flowers earlier – the so-called stress-induced flowering – and much later under very good growing conditions.