When a plant is said to be “poisonous” what exactly does that mean?
Does it mean that all of the plant is poisonous? Or only part of the plant?
How poisonous is it? Very toxic coursing death? Or just a little skin irritation?
Is it poisonous to everyone? Or just those allergic to it?
|Plants may cause poisoning by different pathways such as:|
|Inhalation||Symptoms of hay fever or asthma but smoke of the Oleander plant can potentially cause death|
|Direct contact through the eye||Toxic or caustic sap from the Naked Lady causes pain & irritation often leading to permanent blindness in that eye|
|Direct contact with the skin||Symptoms of swelling rashes or blistering. Poison Ivy, oak, sumac causes contact dermatitis from the oil of the plant (urushiol) that sticks to our skin, but helps the plant retain water|
|Direct ingestion by eating||Symptoms of Diarrhoea, vomiting, gastroenteritis, nervous symptoms, respiratory and /or cardiac distress. Azalia is extremely toxic to cats, dogs and horses but can readily be consumed by goats and sheep|
Some plants are listed as poisonous (and they are) but only if eaten in large quantities while other plants have toxic parts only if eaten by humans and are therefore listed as poisonous. But the likelihood of someone eating a part of these plants is very slim indeed. Who of us is likely to eat the tuber of a Cyclamen? It is highly poisonous and fortunately tastes acrid and bitter so we are more likely to spit it out than eat it.
Then there are plants that are listed as poisonous causing only mild diarrhoea in humans yet if eaten by livestock can cause death. Delphinium can kill within a few hours of ingestion.
Any person may be allergic to a plant especially its pollen. Green couch (discussed in a previous blog) is one of the world’s worst causes of hay fever or asthma and some couches may accumulate cyanide making them toxic to livestock.
Death from poisoning of a plant is very rare and usually dose related though children are at risk of eating berries or flowers that look edible and delicious. Of course to avoid this we need to teach our kids what is edible and not edible out there in the garden as these days many plants from the garden that we generally consider to be weeds, are now part of some people’s everyday diet.
|Some poisonous garden plants to watch out for:|
|Alocasia Macrorrhiza bris botanicals||Cunjevoi (Alocasia macrorrhizos) Any part causes severe irritation & swelling of the mouth. Some cases of children’s death have been reported but is some countries certain varieties are used to feed pigs|
Duranta (Duranta erecta & D. lorentzii) The berries cause sleepiness, fever, swelling of the lips, convulsions & even death in children
Castor oil plant (Ricinus communis) Seeds cause severe purging, vomiting, abdominal cramps delirium & even death. A lethal dose is 2 to 8 seedset.
Dumcane (Dieffenbachia species) Biting the stem or leaves causes copious salivation, intense irritation & burning of the mouth, lips & tongue resulting in speechlessness (hence “Dumb cane”) and the effects may last for several days.
Arum lily (Zanthedeschia aethiopica) All parts are poisonous especially children who ate the white or yellow flower spike. Symptoms are swelling of the tongue & throat, acute gastritis & severe diarrhoea
Angel’s Trumpet (Brugmansia X candida). Seeds, flowers, stem & leaves are potent. Symptoms are dry mouth, difficulty in speech & swallowing, vomiting, diarrhoea, confusion, delirium & tendency to violence with death in some cases.
Oleander(Nerium oleander) Small amounts of any part including sap may be fatal. One leaf or one flower could kill a child. Symptoms are staggering, vomiting, diarrhoea, irregular heart action, dilated pupils & coma leading to death
Naked lady (Euphorbia tirucalli) The milky sap causes temporary blindness and blistering of tender skin. Water will not remove it so use methylated spirits to remove the sap.
Morton Bay chestnut (Castanospermum australe) Raw or even roasted seeds can cause severe painful diarrhoea vomiting & dizziness
Today’s Did You Know…?
…That you can control some caterpillars with specific Bacteria.
The caterpillars of Cabbage White Butterfly, Cabbage Moth, Armyworm, Native Budworm, Light-brown Apple moth, Tomato grub, and Looper Caterpillars are killed by this bacterium
The bacterium is Bacillus thuringiensis (trade name of Dipel) which is a beneficial bacterium found in soil, on plant surfaces & also some insects. It specifically targets caterpillars but is safe on good insects such as ladybirds and bees. It produces a toxin that paralyses the caterpillar’s gut and so stops it feeding. It has now been certified for use in organic gardens by ‘Australia Certified Organic’, so is ideal for use in home gardens using organic methods.