Red Horse Chestnut trees are not as common as the Horse Chestnut in Exeter, but are much the same. The key difference is the colour of the flowers. Instead of being white they range from pink to red as there are several cultivars. They usually flower a bit later than European Horse Chestnut and is typically between May and June. However, they can flower in April if the weather has been suitable. Other than the flowers, the Red Horse Chestnut is much the same as the European Horse Chestnut. It is typically planted in the UK as an ornamental tree in parks and green spaces. During the Autumn it can drop a lot of large sized leaves as well as the hard round cases which can lead to blocked drains as well as quite a bit of mess. For this reason it is not very well suited as a street tree or in paved areas. This tree is a hybrid between the Red Buckeye (Aesculus pavia) and the Horse chestnut (Aesculus hippocastanum). There aren't many of these pretty trees in Exeter which surprises me as they are very suited for our parks and green spaces. There is a small Red Horse chestnut at the Exwick cemetery and also one in the Southernhay gardens.
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The Red horse chestnut can grow to a height of around 8 metres in the form of a small tree or large shrub. It is unclear of he lifespan but both parent trees are usually around 300 years. The bark is smooth and pinky grey when young, which darkens and develops scaly plates with age. The twigs are hairless and stout, the buds are oval, dark red, shiny and sticky.  The buds are some of the biggest you'll ever come across - making them a great species to start with for study.
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The leaf scars of Red Horse chestnut are unmistakable
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The buds are very large but not quite as sticky as the standard Horse chestnut
The palmate leaves comprise of 5-7 pointed, toothed leaflets spreading from a central stem. The leaves tend to be tidier and less prone to leaf blotches and miners than the standard Horse chestnut.
During April the flowers are getting larger and usually bloom in May but sometimes late April
The pink showy flowers are now in bloom during May
The flowers usually appear in May. Individual flowers have 4-5 fringed petals, which are deep pink /red  colour. They are pollinated by insects but also attract hummingbirds (where present). The flowers are hermaphrodite which means both the male and female parts are contained with the same flower.
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The leaves of Red Horse chestnut are 5–7 pointed, toothed leaflets spreading from a central stem
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The husk is not as spiny as the standard Horse chestnut
Once pollinated by insects, each flower develops into a glossy red-brown conker inside a slightly spiky green husk, which falls in autumn. The distinctive large leaves have serrated leaflets and the twigs have large sticky red buds. They are fairly easy to identify all year around. Unlike the fruit of Sweet Chestnut which is edible, Red Horse chestnut are not.
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QUICK FACTS
  • Red Horse chestnut is  is a cross between our common horse chestnut and the red buckeye from USA
  • The leaf stalks leave a scar on the twig when they fall, which resembles an inverted horse shoe with nail holes
  • The conkers used to be ground up and fed to horses to relieve them of coughs, and could be the origin of the tree's name
  •  The palmate leaves comprise 5-7 pointed, toothed leaflets spreading from a central stem
  • In May - individual flowers have 4-5 fringed petals, which are pink or red
  • The flowers are hermaphrodite and are pollinated by insects (in the UK that is)
  • Each flower develops into a glossy red-brown conker inside a spiky green husk, which falls in autumn
  • In winter the twigs have large sticky red buds
  •  It is rarely found in woodland, but is a common site in parks, gardens, streets and village greens
  • It has been in cultivation since the 1820s
  • The first record of the game 'Conkers' is from the Isle of Wight in 1848
  • The flowers provide a rich source of nectar and pollen to insects, particularly bees
  • Caterpillars of the triangle moth feed on its leaves, as well as the horse chestnut leaf miner moth
  • Deer and other mammals eat the conkers
  • The conkers have been used to include horse medicines, as additives in shampoos and as a starch substitute
  • Chemicals extracted from conkers can be used to treat strains and bruises
  • Conkers are actually mildly poisonous and contain a chemical known as aescin, which can induce vomiting and even paralysis
  • Propagation is from seed, an oddity for most hybrids
PLEASE LEAF ME ANY FEEDBACK / COMMENTS
If there is anything out of place or wrong please contact me. Equally if there is anything you wish to add please let me know. The more information we have about Red Horse Chestnut the better. Many thanks!