BEAUTIFUL BUT DEADLY
We grow plants for their beauty, and taste
when we want to consume them, but all plants have a desire for survival so to deter
predators many have developed a massive array of poisons in roots, bark,
leaves, stems, seeds and flowers.
Poisonous plants are
very common in most gardens, e.g. rhododendrons, narcissi and aconites, and
council land and shopping centres are often landscaped with a wide range of
poisonous plants including laurel, snowberry, azaleas, laburnum and yew trees.
Even in the home we
grow hyacinths, poinsettias and oleanders which all contain toxins. However we
need to keep this danger in perspective.
Azaleas in autumn |
Most poisonous plants
are so bitter or foul tasting that they would not normally be eaten, and some
require very large quantities to be ingested before reaching a critical dose.
The leaves of rhubarb
are very toxic containing oxalic acid, but nobody would ever want to eat them,
so there is little problem.
Then there is the
humble spud, a member of the solanaceae family, which has some very poisonous
relatives such as the deadly nightshade and Datura stramonium, the Angel
Trumpets containing tropane. It is used in summer beds, tubs and borders. It
has large highly scented trumpet flowers that are at their best at night. Every
part of the plant is toxic. South American native Indians use it as a drug
because of its hypnotic and hallucinogenic affects.
The toxic house plants
include hyacinths, poinsettias and dumb cane which can cause immobility of the
mouth and tongue, great difficulty in breathing and asphyxiation.
Drift of Aconites |
Toxic weeds include
hemlock containing alkaloids, deadly nightshade which contains the alkaloid
atropine and giant hogweed whose sap is phototoxic and can cause a severe rash
and blisters.
The most toxic tree in
UK has to be the yew tree. Its toxins have protected it so well from foraging
predators that it can last for hundreds of years. The yew was revered as a
sacred tree by Greeks, Romans, North American Indians and in UK by the Celts
and Druids. It was associated with immortality, rebirth, protection from evil
and access to the underworld. Every part of the tree is extremely poisonous,
except the fleshy aril around the seed. The stems, leaves and seeds contain the
toxic alkaloid taxine. The Druids would plant them in circles to protect sacred
ground and monks would use them to mark and protect the routes of their
pilgrimages. Many very old yews survive in churchyards as the sacred ground is
protected.
The Laburnum tree
has beautiful yellow flowers, but all parts of this plant are toxic including
the seeds. The castor oil plant is grown as an ornamental dot plant in bedding
schemes, but the seeds contain ricin, a poison, but in low doses. No poison is
extracted when the seeds are cold pressed to give us caster oil.
Foxgloves may be
attractive as an herbaceous plant, but reproduces from seed very easy so can be
quite invasive. The entire plant is toxic.
Red Opium Poppy |
Opium poppies are
commonly grown for their lovely pink flowers in summer, but all parts of the
plant are poisonous. Opium is extracted from the latex in the seed pods, but
the seeds themselves are edible and used in many recipes.
Wee jobs to do this week
Any spare land
cleared from a previous crop such as spring cabbage or early potatoes can still
be used for sowing lettuce, radish, turnip, peas, carrot and beetroot. These
will be ready to harvest from autumn to early winter.
End