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Name:
'Aesculus' was a Latin name for a variety of
Oak, but it was applied by the great botanist Linnaeus to the
Horse Chestnut. 'Hippo' means 'horse' in Greek and 'kastanos'
means 'chestnut'. The fruits of this tree resemble those of
the (Sweet) Chestnut tree. The horse connection is twofold: Horse
Chestnuts were fed to horses in the East as a stimulant and to
make their coat shine. The leaf-scars on the twigs have the shape
of a horseshoe, including the nail holes. Check it out next time
you get the chance! Cultivation:
Propagation is usually by seed. It's best to plant the
'conkers' straight away outside, because they can quickly lose their power
to germinate on storing. If you cannot plant straight away, store
them in sand so they will not go mouldy and plant in the Spring.
If this is your plan, remember that you have more chance to get
successful seedlings if you allow the seeds to go through a
process called 'stratification'. Stratification aims to mimic the
natural conditions, which the seed would have been subjected to
had it been left outside. Freezing and thawing helps to degenerate
the hard seedcoat sufficiently to promote eventual germination.
The easiest way to do this at home is put your seeds in some damp
(not wet! -or they may rot) sand, peatmoss or vermiculite and
place it at the back of your refrigerator for a couple of months.
An old margarine tub is a useful receptacle to use for such a
project.
Another way to raise Horse Chestnuts is from semi-hardwood
cuttings.
The Red flowering Horse Chestnut is a hybrid from the crossing of A.
hippocastanum x A.pavia. To maintain the full colour of the
flowers the trees are propagated by grafting on a stock from
the seed of A.hipocastanum. Chestnuts are hardy and will be
able to tolerate some drought. Alas it is no longer planted so
much as a street tree, because the volume of autumn leaves and the
numerous falling seeds, which are covered in a spiny husk. Uses:
The wood of the Horse Chestnut is of a poor quality and it is
used for purposes such as making packing cases. As a firewood it
will both make heat and flame, but it tends to spit a lot.
The nuts are rich in starch but they are not suitable for human
food due to the presence of saponins, which are soap-like
chemicals. They have been made into a food for horses and cattle
in the past, by soaking them first in lime-water so reduce their
bitterness. Alternatively they were soaked in water overnight and
then boiled for half an hour and the water thrown away. Then they
were ground up and added to the rest of the fodder.
One of the most well-know uses of the Horse Chestnut is the game
of Conkers. Playing
Conkers:
The autumn is the beginning of the season for the game when all
over the country children collect the nuts. This popular game of
conkers, also known as 'obly-onkers' or 'oblionker' seems to have
originated in the UK. You might think that the word 'conker' comes
from 'conquering' since the object of the game is to wack each
others conquer and destroy them, but there is also a theory that
it come from the conch, since these seashells were used in a
similar game.
Each player has a their
conker on its knotted string. Players take turns at hitting their
opponent's conker. If you are the one whose conker is to be hit
first, let it hang down from the string which is wrapped round
your hand. That 9 inch drop is about right. You must hold it at
the height your opponent chooses and you must hold it perfectly
still.
Your opponent, the striker,
wraps their conker string round his hand just like yours. S/he
then takes the conker in the other hand and draws it back for the
strike. Releasing the conker s/he swings it down by the string
held in the other hand and tries to hit her/his opponents conker
with it. If s/he misses he is allowed up to two further goes. If
the strings tangle, the first player to call "strings"
gets an extra shot. Players take alternate hits at their
opponent's conker. The game is won when one player destroys the
other's conker. In some tournaments a winning conker can then go
on with an enhanced score to do battle with other conkers.
At the Conker World Championships in Ashton, Northamptonshire
(held since 1965 for charity), however, the winner is decided by a
knockout system. During the 2002 Championships on the Village
Green on 12 October, 400 international competitors took part and
Richard Swailes and Liz Gibson gained immortality as male and
female World Champion. To ensure fair play, organisers supplied
the conkers readily drilled and laced, thus preventing the use of
all sorts of tricks to harden the nuts
Some of the ways that were employed by 'hardened' conker players
were soaking the nuts in vinegar, salt or parafin, partially
baking them for about a half hour in the oven to case-harden them,
coating them with clear nail-varnish and storing them in the dark
for a year (the shrivelled ones often seem to get the better of
the young shiny ones.
I don't know how it is officially decided who starts first. In the
playground this was often a matter of whoever shouted something
like 'Obli, obli oh, my first go.'
The Horse Chestnut and
the Politics of War
During the first World War Horse Chestnuts were
gathered by schoolchildren to help make ammunition. It was
used for the production of acetone (of which there was a
great shortage during the War) which, in turn, was needed
for the production of cordite, the smokeless powder used
as propellant in small arms ammunition and artillery.
Cordite is a mixture of the explosives guncotton (65 per
cent), nitroglycerine (30 per cent) and petroleum jelly (5
per cent), gelatinised with the aid of acetone before
being worked into threads for use. David Lloyd George
(Munitions minister at the time) appointed Chaim Weizmann,
a chemist who had emigrated from mainland Europe in 1904,
to increase acetone production using a process of his own
invention involving the bacterial fermentation of starch.
For the sake of security nobody knew where the factories
were and they were send to London. Maybe it was due to
this, as well as other transport difficulties that there
were letters to The Times reporting piles of rotting horse
chestnuts at railway stations. Lloyd George was very
grateful to Weizmann. So much so that on becoming prime
minister he gave Weizmann direct access to the foreign
secretary, A. J. Balfour. The result was the famous and
controversial "Balfour Declaration" of 2
November 1917 stating that the British government viewed
with qualified favour "the establishment in Palestine
of a national home for the Jewish people". When the
state of Israel came into existence, Weizmann was elected
as its first president in 1948 and held that position
until his death in 1952. Lloyd George himself said
that the acetone problem left "a permanent mark
on the map of the world". However some commentators
point out that the USA Zionist lobby may have played a
role as well, since Britain was of course keen to involve
the USA as an ally in the war. Horse
Chestnut Medicine:
In herbal medicine the fruits of the Horse Chestnut have been
used traditionally for varicose veins, varicose ulcers and other
problems related to the condition of the venous blood-vessels,
such as oedema due to high venous pressure, phlebitis,
haemorrhoids, etc. Modern research has confirmed that they have an
excellent
tropho-restorative action on the veins, increase peripheral
circulation and are astringent and toning. The Horse chestnut is
ideally used both internally as a tincture, as well as externally
made into a lotion,gel or a cream.
Horse Chestnut has also been used for fever and diarrhea. Do not
use this medicine at the same time as aspirin or other blood
thinners.
Horse chestnut
bleeding canker
by Joan Webber and
Kath Thorpe, Forest Research, Alice Holt Lodge, Wrecclesham,
Farnham GU10 4LH
written as a
Tree Damage Alerts produced for the benefit of the arboricultural
profession and issued by the Arboricultural Advisory and
Information Service.
Bleeding canker of
Horse chestnut (Aesculus hippocastanum) was first recorded in the UK
in the 1970s (Brasier and Strouts, 1976) and has become increasingly
common over the past 4 or 5 years. We know relatively little about
this disease, other than it is caused by two species of Phytophthora
– P. cactorum and P. citricola. The process of infection is also
unknown.
Symptoms
Horse chestnut trees have cankers,
which initially may be apparent as a crack in the bark on the stem and
occasionally on large branches. These ooze rusty-red, yellow-brown or
almost black gummy liquid which dries forming a dark coloured, brittle
crust. Over several years the fungus can extend through the phloem and
cambium of the tree and may even girdle the entire stem or branch. Large
or numerous lesions are often associated with extensive yellowing and
thinning of the crown, and eventually crown death. In some cases, parts
of the crown often associated with individual branches, will fail to
flush, and later in the year the remaining foliage withers and dies
Infection and Diagnosis
Infection and disease
development are very unclear. Warm and wet conditions may optimise
the risk of infection as Phytophthora spores tend to be dispersed in
rain splash and via mist.
Confirming the
diagnosis of horse chestnut bleeding canker can be difficult.
Bleeding canker is distinct from Phytophthora root disease; here
tree stems are infected by the fungus growing up from infected roots
or root collars. In contrast, stem or branch lesions giving rise to
bleeding cankers are not connected to root infections, suggesting
that the Phytophthora species involved can cause direct infection of
bark, in the absence of any wound or injury.
Confusion with other
diseases - The symptoms on Horse chestnuts can look very similar to
stem bleeding due to infection by Phytophthora ramorum. This causes
Sudden Oak Death in the USA. Despite the similarities, bleeding
canker of Horse chestnut is caused by different species of
Phytophthora. Unless a horse chestnut with bleeding canker is near
to a source of P. ramorum disease such as infected rhododendrons,
the chance of it being caused by P. ramorum is remote.
Confusingly, mycelium
and fruit bodies of other fungi (e.g. Armillaria species) may also
be present. These result from secondary infection.
Why the bleeding
increase? - We don’t know why there has been such a rise in the
reported incidence of Horse chestnut bleeding canker in the last few
years. The trend towards milder winters and wet springs might
increase the likelihood of infection. Until recently, the disease
was considered to be uncommon and had only been reported from the
south of England (Strouts and Winter, 2000). Reports from 2003
indicate it has spread as far north as Glasgow. Trees of all ages
have been found with the disease, but the impact is most striking on
large, mature trees. Apart from Horse chestnut, bleeding cankers
associated with P. citricola and P. cactorum have also been recorded
on Limes (Tilia species) although, interestingly, there has not been
a corresponding increase in the number of reported cases.
Can we control the
disease? - There are no fully effective control measures although
Strouts and Winter (2000) report that if the cankers are small, it
may be possible to excise the infection by cutting out all the dead
and necrotic bark, and then treating the wound with a paint based on
a fungicide approved for use against Phytophthora. They recommend
sterilising the cutting blade and removing a strip of bark at least
5cm wide from around the periphery of the canker. All excised bark
should then be collected and burned
References:
* Brasier, C. M. and
Strouts, R.G. (1976). New records of Phytophthora on trees in
Britain. Phytophthora root rot and bleeding canker of horse chestnut
(Aesculus hippocastanum L.). European Journal of Forest Pathology 6,
129-136.
* Brasier, C.M. et al (in press). First report of Ramorum bleeding
canker on Quercus falcata caused by Phytophthora ramorum. Plant
Pathology
* Strouts, R. G. and Winter, T. G. (2000). Diagnosis of ill-health
in trees. The Stationery Office, Norwich.
Note from webmother to
page visitors:
Many of these pages are still bare bones. Whenever time allows, we
will continue to add information to the Tree Gallery until all the
trees have descriptions of their habitat, characteristics,
cultivation, uses and anything else of interest. Why not get involved with enhancing this web resource by sending
photographs of trees, bark, details of branches, leaves, flowers, seed
and fruit in all seasons (Good use of all these new digital cameras!). Email us if you
are keen to know more about a particular tree and we will do our
best to complete that one next.
Traditional knowledge:
The-Tree offers a page where
you can read the entry for Horse
Chestnut from "A Modern Herbal" (Mrs. M. Grieve, ed. Mrs.
C.F.Leyel) published in 1931. Obviously things have moved on
since then, yet this book is still often unsurpassed in its scope
and depth of traditional knowledge. The page pops up in a new
window. Close it to return to the Tree Gallery. |
