Learning Centre

Accidental Poisoning: SEQ Plants That Can Harm Humans and Animals

Written by Trevor Dixon | Jan 14, 2026 4:30:00 AM

Introduction

Subtropical gardens in South East Queensland are an explosion of colour, texture, and life. They flourish year-round, nourished by warm weather and seasonal rains. But amidst the beauty, a quiet danger thrives. Certain common plants — beloved for their showy blooms or architectural foliage — contain potent toxins. These plants pose a threat to curious children, playful pets, and even unsuspecting adults. Accidental poisoning happens more often than many realise, often in places considered safe: our very own backyards.

Understanding Plant Toxicity in SEQ

South East Queensland’s climate is an ideal incubator for a wide array of plant life — both native and exotic. Unfortunately, this includes species that defend themselves with chemical compounds. These toxins may deter grazing animals in the wild, but in a home setting, they can cause real harm.

Many of the most toxic plants are also the most visually striking — an evolutionary trick that fools many gardeners. Knowing how to identify and manage them is a vital part of safe horticulture in this region.

Common Offenders in SEQ Gardens

Oleander (Nerium oleander)

A robust evergreen shrub with masses of colourful flowers. Every part is toxic — from leaf to flower to sap. Ingestion can lead to vomiting, slowed heart rate, and in extreme cases, cardiac arrest.

Angel’s Trumpet (Brugmansia spp.)

Elegant, fragrant, and deadly. This small tree’s trumpet-shaped flowers contain alkaloids that can cause hallucinations, seizures, and respiratory failure if consumed. Even inhaling the scent in enclosed spaces has been reported to cause symptoms in sensitive individuals.

Mother of Millions (Bryophyllum spp.)

This succulent spreads quickly and is incredibly hardy — but it contains bufadienolides, compounds that can cause heart failure in pets and livestock. Accidental ingestion of a few leaves can be fatal to cats and dogs.

Castor Oil Plant (Ricinus communis)

Known for its architectural foliage and spiky seed pods, this plant produces ricin — a deadly toxin even in small amounts. Ingesting just a couple of seeds can lead to severe vomiting, internal bleeding, and organ failure.

Dumb Cane (Dieffenbachia spp.)

Commonly grown indoors, this plant has large variegated leaves. It contains calcium oxalate crystals that cause burning, swelling, and potential airway obstruction if chewed. Children and pets are particularly vulnerable.

Coral Tree (Erythrina spp.)

Often used as a shade or street tree, Coral Tree produces beautiful red flowers and curious seed pods. The seeds are highly toxic and attractive to young children. Ingestion can lead to nausea, tremors, and in high doses, paralysis.

Green Cestrum (Cestrum parqui)

This woody shrub with lime-green foliage and tiny yellow flowers is deceptively dangerous. It causes liver failure in animals and acute poisoning symptoms in humans — especially when berries are consumed.

How Accidental Poisoning Happens

In most cases, poisoning isn’t deliberate. It happens when:

  • Children explore the garden and taste a flower or berry.

  • Pets chew on leaves while playing or grazing.

  • Gardeners handle toxic plants without gloves and then touch their eyes or mouths.

  • Composting or burning plant material releases harmful compounds.

  • Misinformation leads to planting harmful species close to play areas or kennels.

These common occurrences can have serious outcomes if not identified early.

Symptoms to Watch For

In Humans

  • Nausea and vomiting

  • Skin or eye irritation

  • Difficulty breathing

  • Excessive drooling or throat swelling

  • Irregular heartbeat

  • Confusion or dizziness

In Animals

  • Sudden vomiting

  • Drooling or pawing at the mouth

  • Tremors or seizures

  • Loss of coordination

  • Lethargy or collapse

If any of these symptoms appear after potential contact with a plant, immediate action is essential.

Responding to a Suspected Poisoning

Time is critical. Here’s what to do:

  1. Do not induce vomiting unless directed by a professional.

  2. Rinse the mouth or affected area gently with clean water.

  3. Secure a sample or photo of the plant for identification.

  4. Contact a poison helpline immediately:

    • Queensland Poisons Information Centre: 13 11 26

  5. Transport the patient (human or animal) to a medical facility or vet as advised.

Never rely on online forums or social media for diagnosis — professional help saves lives.

Prevention Is the Best Cure

  • Audit your garden: Know every plant in your landscape. Remove or relocate toxic species away from high-use zones.

  • Use child- and pet-safe alternatives: Opt for non-toxic natives and ornamentals like lomandra, native violets, or blue flax lily.

  • Label unusual plants clearly: Especially if they are in shared community spaces or rental properties.

  • Educate kids: Teach them that not everything pretty is safe to touch or eat.

  • Supervise pets: Avoid free-roaming in gardens with questionable species.

  • Wear gloves when pruning or handling plants: And wash hands before eating or drinking outside.

A proactive gardener is a responsible one — and prevention is always easier than treatment.

Conclusion

Gardens are meant to nurture — to be sanctuaries of beauty and life. But in SEQ, that same lushness can conceal a host of threats. Accidental poisoning from common plants is not a rarity; it is a real risk that deserves attention.

With careful plant selection, early identification, and thoughtful design, your garden can remain a vibrant haven — without the hidden dangers. Let your garden grow wild with wonder, not risk.