Diarmuid Gavin: Poisonous plants... even the most innocent-looking plants can be deadly
Walking recently on a riverbank in Co Wicklow late in the evening, I spied an interesting-looking plant. In the dim light, I could make out the luminous white heads of flowering giant hogweed (pictured right). It's a plant I have always loved - a dramatic visual delight!
However, it's a plant I know never to encourage and one that gardeners would never specify in a planting scheme. And if I see young species, especially thriving beside water, I always recommend that it is eradicated on sight. Why? Because it's dangerous to humans. Even brushing against it can cause blistering rashes. It's an inviting plant because it's so dramatic - standing next to it would dwarf a person.
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We really need to be aware of this and other plants that can do us harm, as even in gorgeous ornamental gardens, we can be surrounded by innocent-appearing, and often beautiful-looking, dangers.
Some, like the common foxglove, may seem too familiar to be a threat, while others such as Atropa belladonna (deadly nightshade) always come with a skull-and-crossbones warning. And while the juice of some plants can be soothing, such as aloe, last year it was reported that a gardener died after just brushing against Aconitum (monkshood).
So, what plants do you need to be careful with? If you have children, you need to be aware of plants with bright berries that look tempting but can be very toxic. These include cuckoo pint (Arum italicum), which have bright orange poisonous berries, as well as the fruit of cherry laurel, privet and Rhamnus (buckthorn).
People often fret about laburnum trees and while it's true the seed pods are toxic, because they are black and hard, they're not that attractive to children. Besides this, children need to be taught not to eat anything without adult permission and what the consequences can be.
Yew berries are poisonous - not the flesh, but the seed. Yew foliage is toxic so be careful when disposing of clippings so animals won't be tempted. Horses are particularly vulnerable if they eat something toxic, as they haven't the ability of dogs and humans to vomit it up.
Some gardeners don't like to wear gloves but it's definitely necessary sometimes when handling or pruning plants whose sap can burn, such as euphorbia or those hairy plants such as echium and fremontodendron, which can irritate.
If you have sensitive skin, you'll need to wear long sleeves and trousers. Reactions can vary from itchiness to blisters and rashes so be aware when handling ivy, ficus, parsnip, hellebores, schefflera and rue (Ruta).
If you want the full list, the Royal Horticultural Society has compiled a list of potentially harmful species - all of which are harmless if not touched or eaten. It's worth remembering that some of these on the list have saved many more lives than they have taken - for example, foxglove, from which the heart drug digoxin is made; yew, from which we get Taxol, the cancer-fighting drug, and St John's Wort, used for its antidepressant properties. Mother Nature is a powerful force but must be handled with respect and common sense.
If you're in the Blarney area over the summer holidays, you may be intent on kissing the stone. But hidden behind the castle battlements, there's another curious attraction... a poison garden which you're encouraged to enter but "at your own risk".
The resident plants are said to be so dangerous and toxic that they must be kept in large cage-like structures!
It contains a collection of poisonous plants from all over the world including wolfsbane, mandrake, ricin, opium and cannabis.
Many of these are labelled with information about their toxicity, and traditional and modern uses. A large number of plants that we now know to be toxic were once used widely as herbal remedies for all sorts of ailments.
It appears that the old expression "It will either kill you or cure you" could not have been more apt!
Common garden plants that should not be ingested include foxglove, the castor oil plant (Ricinus communis), delphiniums, lupins, bluebells, amaryllis, symphytum (above), brugmansia and Daphne.