Plants in the garden to be cautious of

Australia is known as the lucky country – but to be honest sometimes you may wonder how we all survive in this wonderful country. What with the dangerous snakes, killer jelly fish, deadly spiders, giant birds and drop bears (only kidding about that one). So now I am going to tell you about plants in your garden that you need to approach with caution.

Survival of the species

Plants need to survive and rely on various methods to protect themselves. 

Direct defences such as hairs, trichomes, thorns and spines offer mechanical protection and the production of toxic chemicals such as terpenoids, alkaloids, anthocyanins, phenols, and quinones that either kill or retard, help to ensure plant survival. 

Idioblasts (specialized plant cells) are an example. Idioblasts detonate when the first line of defence has been breached. 

The Dieffenbachia, a common houseplant, contains Idioblasts that fire barbed calcium oxalate crystals into the mouths of predators and can cause paralysis.

Plants under stress will release volatile organic compounds to warn other plants of impending danger. They may increase concentrations of toxic compounds to ward off the enemy, or they may release compounds of their own that attract the enemy’s predators.

Plants even have the ability to protect themselves from sunburn – they are very good at producing self-defence mechanisms against UV-B, such as enzymes to repair sun damage, and antioxidants, which neutralise damaging free radicals produced by UV-B rays. This is why we eat our antioxidants, - to neutralise free radials. 

And then there are poisons, but what maybe a poison to us may be harmless to another species. We harness some of these attributes of plants for our own uses. Pyrethrin obtained from chrysanthemum plant, used as an insecticide is an example.

Poisonous plants

Obviously, there are quite a number of plants in Australia that may cause concern so here is a list of just a few according to Australian Geographic.

• Moreton Bay chestnut or Black bean (Castanospermum australe) eating the seeds can cause vomiting and diarrhoea. Medical attention needs to be sought.
• Oleander (Nerium oleander). Most people are familiar with the oleander plant. This plant has a bitter taste so most people would avoid eating it – but it can kill a child if consumed. The leaves can cause skin irritation and if burnt the fumes can be toxic
• Strychnine tree (Strychnos nux-vomica) the seeds of this plant are highly poisonous having a neurotoxic effect on the nervous system of the body causing convulsions, paralysis and even death. The bark and blossoms may contain the poison alkaloids strychnine and brucine. Nux-vomica can be found in homeopathic medicine, which is safe naturopathic medicine based on like treats like, and this particular ingredient is used for nausea and vomitting.
• Angel's trumpets (Brugmansia spp.) This plant is highly toxic and ingesting it can cause severe symptoms of diarrhoea, migraines, confusion and may result in death
• Deadly nightshade (Atropa belladonna) known to cause hysteria, hallucinations, erratic behaviour and delirium. One leaf can be fatal to adults. Belladona is another formula found in homeopathic medicine.
• Milky mangrove (Excoecaria agallocha) common name- 'blind-your-eye-mangrove'. As the common name suggests, this plant can cause a temporary blindness and skin irritation.
• Spurge (Euphorbia spp.) This plant can cause severe irritation of the eyes, mouth and nose and even blindness.
• Nettle family (Urticaceae) touching species of this plant can cause severe skin irritation and pain. Interestingly, nettle (Urtica urens) is a popular herbal medicine remedy used to treat itchy skin rashes and inflammation.

Common symptoms of poisoning include:

• Vomiting
• feeling sick
• diarrhoea
• pain in stomach
• feeling dizzy or weak
• temperature above 38°C
• chills (shivering)
• loss of appetite
• headache
• irritability
• difficulty swallowing
• salivating
• skin rash
• blurred vision
• seizure

Call the Poisons Information Line 24 hours a day from anywhere in Australia on 13 11 26 If you are concerned you have been poisoned or seek medical help immediately if life is threatened.

Protecting yourself from harm in the garden

Not all the hazards in the garden come from poison. From some plants it’s the dangers from falling seed pods, such as with the Bunya Pines that can drop a huge seed pod that may weigh as much as 18kg.

Other concerns can be allergies. Just mowing the lawn can cause irritating allergy symptoms for some people. If you are one of these it may be helpful to take an antihistamine before you spend time in the garden.

Natural therapies such as Vitamin C and quercetin Albizzia lebbeck can help counteracting the allergic response. Echinacea can support immune function, Eyebright (Euphrasia offincinalis) and Goldenseal (Hydrastis canadensis) are useful anticatarrhal herbs.

Let’s not forget our furry friends in the garden

Beware of dangerous plants and garden poisons for our 4-legged friends. According to the RSPCA (Royal Society for the Prevention of Cruelty to Animals) common causes of poisoning in pets include:

Rodent poison (rat and mice poison) which can cause uncontrolled bleeding in animals – get your pet to the veterinary for immediate attention if you suspect rodent poisoning. Try an alternate method of pest control such as snap traps, live trapping and rodent proofing your home.

Snail and slug bait resembles cat or dog biscuits so are attractive to our pets. Unfortunately, consuming only a small amount can lead to death.

Plants – basically all indoor and out door plants are toxic to pets. Seeds and berries can poisonous to animals but also cause digestive blockages.

Garden fertilisers some may just cause digestive distress and maybe self- limiting if consumed in small quantities only. But some products contain bacteria and fungus, and like in humans are dangerous.

Other concerns are the insecticides which are highly toxic to animals.

Other concerns

Like humans, dogs can suffer from allergies, particularly seasonal from plants in the garden. Itchy skin rashes and sneezing can be symptoms of allergies.

References

1. Mechanisms of plant defence against insect herbivores https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3493419/
2. How do plants protect themselves against sunburn? https://www.britannica.com/list/botanical-barbarity-9-plant-defense-mechanisms
3. https://cosmosmagazine.com/biology/how-do-plants-protect-themselves-against-sunburn
4. https://www.healthdirect.gov.au/poisoning
5. http://www.australiangeographic.com.au/topics/science-environment/2012/07/australias-most-poisonous-plants/
6. http://kb.rspca.org.au/what-garden-dangers-must-i-protect-my-pet-from_314.html
7. http://kb.rspca.org.au/what-is-the-most-humane-way-to-kill-pest-rats-and-mice_139.html
8. http://www.abc.net.au/local/photos/2014/02/14/3945284.htm
9. https://en.wikipedia.org/wiki/Araucaria_bidwillii
10. Mills, S, and Bones, K., 2009, Principles and Practices of Phytotherapy Modern Herbal medicine, Churchill Livingston