Horse chestnut vs sweet chestnut: 4 differences


I am a student of agricultural sciences and a real country kid. At home, I love tending my small vegetable garden and spending time out in nature. When not outdoors, I love to write. Beyond gardening and writing, however, I am particularly passionate about wildlife.

Favourite fruit: currants and raspberries
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What is the difference between horse chestnuts and sweet chestnuts? Are both chestnuts edible? Here are the four most important differences.

A horse chestnut conker
Horse chestnut fruits are not edible [Photo: 9196924/]

Chestnuts are a popular autumn treat enjoyed by many. However, it can be tricky collecting your own chestnuts in autumn, as not all chestnuts are the same. Only a few varieties of chestnuts are edible. In the UK, both the inedible horse chestnut (Aesculus hippocastanum) and tasty sweet chestnut (Castanea sativa) can be found in many gardens. Fortunately, distinguishing between horse chestnuts and sweet chestnuts is quite easy. There are several distinguishing features that you can use to tell the trees apart.

Which chestnuts can you eat?

Around twelve species belong to the chestnut genus (Castanea), including the sweet chestnut, the Japanese chestnut (Castanea crenata) and the American chestnut (Castanea dentata), all of which are edible for humans. In contrast, the horse chestnut, which is also found in the UK, does not belong to the chestnut family but rather to the soapberry family known as Sapindaceae. Horse chestnuts are not suitable for consumption and cause nausea and vomiting when ingested. So, if you were wondering whether you can eat sweet chestnuts or horse chestnuts, definitely stick to the sweet ones.

CharacteristicHorse ChestnutSweet Chestnut
Fruit huskFew, thorn-like spinesMany, needle-like spines
FruitRound, sphericalFlattened and hairy tip
Flowering timeApril to JuneJune to July
FlowerStriking, erect flower corollasInconspicuous flowers resembling willow catkins
Leaf shapeFive-limbed, almost hand-shapedElongated oval, serrated edge

Horse chestnus vs sweet chestnut: What is the difference?

Unlike sweet chestnuts, horse chestnuts are not edible for humans or pets because they contain poisonous saponins. The two types of chestnut also differ externally. The shape of their fruits, their fruit shells and the appearance of their leaves and flowers are distinct.

Difference 1: fruits

Horse chestnut and sweet chestnut fruits are enough to tell the two types of chestnut apart. The fruits of the horse chestnut, commonly known as conkers, have a very spherical shape. Sweet chestnuts, on the other hand, are somewhat flattened and taper to a point at the end. The pointed ends of sweet chestnuts are also often surrounded by brush-like hairs.

Sweet chestnut fruits and casings
Sweet chestnut seeds come to a point at the end [Photo: waldenstroem/]

Difference 2: pericarp

The spiny casing is one of the most distinctive features for identifying horse chestnuts and sweet chestnuts. Even though, at first glance, the fruit casings of the chestnuts look similar, a closer look reveals clear differences. Horse chestnuts have a leathery husk covered somewhat sparsely with pointed thorn-like spines, whereas sweet chestnut husks are densely covered with needle-like spines.

Grouping of sweet chestnut burrs
Sweet chestnut burrs are densely covered with long spines

Difference 3: leaves

You can also tell chestnut trees apart by looking at their leaves. Horse chestnut leaves are palmate and usually have five to seven lobes. They are often used for decorative purposes. Sweet chestnut leaves, on the other hand, are simple and ovate or lanceolate. Their serrated edge also clearly distinguishes them from the leaves of the horse chestnut.

Sweet chestnut burrs and leaves
The sweet chestnut has ovate serrated leaves

Difference 4: blossoms

If you want to find out which trees will bear edible sweet chestnuts and which will bear horse chestnuts, pay close attention to the blossoms in spring. Horse chestnut trees have branched clusters of white flowers that grow upright, which make the tree particularly popular as an ornamental. The flowers of the sweet chestnut, on the other hand, are inconspicuous and strongly resemble willow catkins. The flowering times of the two trees are also different. Horse chestnuts blossom from April to June, whereas sweet chestnut flowers appear between June and July.

Horse chestnut inflorescence with flowers
The horse chestnut has beautiful showy flowers [Photo: DmyTo/]

What is the difference between chestnuts and marrons?

Marrons are not an independent species but a special cultivation of the sweet chestnut. Marron chestnuts have a more aromatic flavour, and their fruits are a bit larger and rounder. Marrons are also easier to peel than chestnuts, which makes them more popular in the kitchen.

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