Plants Which are Toxic

There is an increasing awareness amongst the general public about the toxicity of certain plants which is, in some quarters at least, bordering on the hysterical an thus threatening the removal from sale of many much-loved plants.

In the interests of allowing our customers to make an informed decision about the suitability of plants for their farm, estate or garden, our own troll through veterinary and botanical reference books has enabled us to assemble the following list of plants (sold in our webshop) over which some caution should be exercised. Many of the entries here clearly relate to animals/livestock and whilst it would be reasonable to expect the same plant to be toxic to humans, the chances of the situation arising whereby, for instance, a child would eat Rhododendron leaves in sufficient quantity to cause severe poisoning, are quite remote.

We have taken great care in the compilation of this list and believe that it reflects the latest thinking on the subject, but must disclaim any responsibility for subsequent events demonstrating that the list is not exhaustive and thus point out that it is provided for your guidance only!

Toxic Plants

Aesculus (sp.). Common name Horse Chestnut/Conker.
Eating any of the parts growing above ground can cause an upset stomach.

Buxus (sp.). Common name Boxwood.
All parts toxic; can be fatal.

Cuprocyparis leylandii. Common name Leyland Cypress
Contact with the sap may irritate the skin. Inhalation of the smoke when the plant is burned may trigger an allergic reaction. All parts toxic to horses.

Daphne mezereum.
Bark and berries intense irritants; can be fatal.

Euonymus europaeus.
Fruit, leaves and bark all violent emetics and purgatives.

Frangular alnus.
Fresh fruit and bark a powerful emetic.

Gaultheria.
All parts are potentially toxic and may cause vomiting, low blood-pressure and changes in heart rhythm.

Hedera (sp.).
All parts are toxic but not quite as toxic as folklore would have us believe.

Hypericum.
Ingestion of any plant material causes increased sensitivity of the skin to sunlight, resulting in reddening and blistering.

Ilex (sp.).
Berries are a violent emetic and purgative.

Kalmia.
All parts are potentially poisonous, but cases are rare as the plant is unpalatable.

Laburnum (sp.).
All parts are toxic, can be fatal. when a Laburnum stick is thrown for a dog to fetch it can cause serious ulceration of its mouth.

Ligustrum (sp.).
All parts toxic.

Prunus laurocerasus & P. lusitanica.
Foliage highly toxic, can be fatal. As with Rhododendron, livestock ill normally leave it alone but, after heavy snowfall, it may well be the only greenery on view on within reach and it is then that it will be tried.

Quercus (sp.).
Animals can find acorns (and, to a lesser extent, foliage) quite addictive and excessive consumption can lead to poisoning by the tannins contained within. Once discovered, a beast will break down or jump fences to reach them again.

Rhamnus cathartica.
'Purging Buckthorn' berries are a powerful purgative.

Rhododendron.
Foliage highly toxic, can be fatal. (See Prunus laurocerasus).

Sympthoricarpos.
Eating the berries may cause vomiting, confusion, dizziness and diarrhoea.

Taxus (sp.).
All parts toxic, even after drying . Can be very quick acting - livestock will often still have foliage in their mouths when found dead. For some reason Roe deer (and maybe other species) can eat Yew with impunity.

Plants Which Are Toxic - Sources

Sources

'Poisonous Plants and Fungi' by Pamela M North - Blandford
'British Poisonous Plants' by A A Forsyth - HMSO Bulletin 161.
'Poisoning in Veterinary Practice' by A H Andrews and D L Humphreys - The National Office of Animal Heath.
BBC Gardeners' World

Useful Related Websites

WikipediaGood Old Wikipedia; often a good starting point, but not utterly reliable.
RHSRHS website information that is very clearly laid out and very helpful.

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