10 toxic ornamental plants you might have in your garden
Some widely sold ornamentals contain natural toxins or irritants that can affect pets, wildlife and even the people maintaining them. Ingestion of certain leaves, berries or bulbs may cause vomiting, organ damage or neurological symptoms in animals. Sap from some species can irritate skin or eyes during pruning.
These plants evolved these chemical defences in their native environments to deter grazing animals and insects. In suburban gardens, those same compounds remain active.
Here are ten commonly grown ornamental plants that may be worth reconsidering, along with safer Australian native alternatives and practical guidance for removal. If a plant is large, well established or difficult to manage safely, consider engaging a qualified professional.
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1. Oleander (Nerium oleander)
Oleander is native to the Mediterranean region, North Africa and parts of the Middle East. It evolved in hot, dry climates where grazing pressure and water scarcity are common. To protect itself, the plant produces cardiac glycosides — compounds that disrupt heart function if consumed.
All parts of the plant contain these toxins. The milky sap may also cause skin irritation in some people.
To remove, cut the shrub back in sections to reduce bulk. Use sharp bypass secateurs for smaller stems, long-handled loppers for thicker growth and a pruning saw for mature trunks. Avoid crushing stems, as damaged tissue can release more sap. Wear thick gloves, long sleeves, long trousers and eye protection. Wash hands and tools after handling. Collect all cut material and dispose of it in green waste rather than composting. You will need a sharp spade and mattock for the root ball.
Australian native alternatives
Lilly pilly (Syzygium species) for hedging in coastal and temperate climates, forming dense evergreen screens with glossy foliage and bird-attracting berries.
Bottlebrush (Callistemon species) in temperate and subtropical gardens, producing nectar-rich flower spikes that support bees and native birds while tolerating heat and periodic drought.
Paperbark or honey myrtle (Melaleuca species) for tougher, drier regions, offering resilient foliage, textured bark and habitat value in low-maintenance native plantings.
2. Sago palm (Cycas revoluta)
Sago palm is an ancient cycad native to southern Japan. Cycads are among the oldest seed plants on Earth and evolved potent chemical defences long before modern mammals existed. All parts of the plant contain toxins, but the seeds are especially dangerous. Ingestion by dogs can cause acute liver failure and neurological symptoms. Because the bright orange seeds fall to the ground when mature, they present a particular risk in suburban gardens.
To remove, begin by cutting off the stiff fronds using long-handled loppers or a pruning saw. Wear thick gloves, long sleeves and eye protection as the fronds are rigid. Dig out the entire root ball using a spade and mattock. Cycads can reshoot if the base is left in the soil, so remove as much of the crown as possible. Do not compost plant material and wash and oil tools thoroughly after use.
Australian native alternatives
King palm or bangalow palm (Archontophoenix cunninghamiana) for subtropical and coastal climates, offering a tall elegant canopy suited to humid conditions and sheltered gardens with consistent moisture. This is a large species and requires ample space to mature.
Cabbage tree palm (Livistona australis) for temperate east coast gardens, providing architectural form and valuable habitat in moist soils along creek lines and coastal regions.
Grass tree (Xanthorrhoea species) for warm, well-drained sites, delivering sculptural form and long-lived resilience in sandy or gravelly soils across a wide range of Australian climates.
3. Lantana (Lantana camara)
Lantana is native to Central and South America and was widely introduced as an ornamental shrub for its bright, long-lasting flowers. In its native habitat, it evolved chemical compounds in its leaves and unripe berries to deter animals and insects. In Australia, lantana has become invasive in many regions, producing heavy thickets and causing illness in livestock and pets if consumed. Contact with the plant may also cause mild skin irritation in some people.
Wear gloves, long sleeves and sturdy footwear, as stems can be woody and tangled. Use sharp loppers or a pruning saw to cut stems close to ground level. For established plants, dig out the crown and major root mass with a spade. Lantana can reshoot from root fragments, so remove as much of the base as possible. Monitor the site for regrowth and remove seedlings promptly.
Australian native alternatives
Grevillea (Grevillea species) for temperate to arid zones, offering nectar-rich flowers that support birds and pollinators while tolerating poor soils and low rainfall.
Banksia (Banksia species) for sandy coastal regions, providing striking flower cones and hardy foliage adapted to wind, salt spray and well-drained soils.
Hakea (Hakea species) for dry inland climates, delivering tough drought-tolerant structure and seed-rich habitat suited to harsh, low-nutrient environments.
4. Foxglove (Digitalis purpurea)
Foxglove is native to Europe and western Asia, where it grows in woodland clearings and disturbed soils. It produces cardiac glycosides, including digitoxin, as a defence against grazing animals. These compounds interfere with heart rhythm when ingested. While valued for its tall vertical flower spikes in cottage-style gardens, all parts of the plant are toxic if consumed. Ingestion can cause nausea, vomiting and heart irregularities in humans and pets.
Wear gloves when pulling young plants by hand. For established specimens, cut flower spikes before they set seed. Use a garden fork to loosen soil and lift the taproot carefully. Remove all plant material from the area and avoid composting seed-bearing stems. Wash hands and tools after handling.
Australian native alternatives
Tall mint bush (Prostanthera lasianthos) in temperate regions, offering upright stems covered in pale tubular flowers suited to sheltered gardens with good drainage.
Thomas N. — Modificado y subido por Philmarin, CC BY-SA 2.5, via Wikimedia Commons
Kangaroo paw (Anigozanthos species) for sunny, well-drained climates, producing bold vertical flower spikes that tolerate heat and attract nectar-feeding birds.
Heath (Epacris species) for cooler climates, delivering fine-textured foliage and delicate tubular blooms suited to woodland and alpine-style gardens.
5. Rhododendron and azalea (Rhododendron species)
Rhododendrons and azaleas belong to the same botanical genus and are native to parts of Asia, Europe and North America. They evolved grayanotoxins as a defence against grazing animals and insect attack. These compounds interfere with nerve and muscle function when ingested. In pets, ingestion can cause vomiting, weakness, low blood pressure and heart rhythm disturbances.
Wear gloves and long sleeves when pruning or removing these shrubs. Use sharp loppers or secateurs to reduce the canopy before digging. For established plants, cut back growth to make access easier, then dig out the root mass with a spade. Rhododendrons have fibrous root systems, so remove as much of the root ball as possible to prevent regrowth. Dispose of plant material responsibly and avoid composting large quantities of foliage.
Australian native alternatives
Correa (Correa species) for temperate and coastal climates, producing pendulous bell-shaped flowers that attract small birds and thrive in well-drained soils with light shade.
Boronia (Boronia species) for cool temperate gardens, offering fragrant foliage and delicate blooms suited to protected positions with good drainage.
Crowea (Crowea species) for eastern Australian conditions, providing long flowering periods and compact evergreen form ideal for temperate gardens.
6. Agapanthus (Agapanthus praecox)
Agapanthus is native to South Africa, where it evolved in open grasslands and coastal environments exposed to grazing pressure. The plant produces irritating sap and compounds within its leaves and fleshy roots that discourage herbivores. Agapanthus can cause skin irritation when handled. The bulbs and leaves may also cause mild gastrointestinal upset if ingested by pets. In some parts of Australia, especially coastal regions, it is considered invasive.
Removing agapanthus can be physically demanding, particularly if the clumps are mature. The root mass forms a dense, fibrous network that is difficult to cut through and may extend deeper than expected. Wear thick gloves, long sleeves and sturdy footwear. Use a sharp spade to cut around the perimeter of the clump first. A mattock or crowbar can help lever the root mass from the soil.
Australian native alternatives
Mat rush (Lomandra species) for coastal and inland climates, forming tough clumping foliage that tolerates wind, drought and poor soils while stabilising garden beds.
Flax lily (Dianella species) for temperate and subtropical gardens, offering strappy leaves, seasonal flowers and bright berries that attract birds.
Bulbine lily (Bulbine bulbosa) for drier grassland regions, producing cheerful yellow star-shaped flowers adapted to open sunny conditions and well-drained soils.
The most toxic plant
The most toxic plant in the world is widely considered to be the castor oil plant (Ricinus communis), which produces ricin — a poison so potent that a single milligram is estimated to be lethal to an adult. It is commonly found growing wild across Australia, often along roadsides, creek banks and disturbed ground.
7. English ivy (Hedera helix)
English ivy is native to Europe and western Asia, where it evolved saponins and bitter compounds to deter grazing animals and insect damage. These chemical defences make the foliage unpalatable and can cause gastrointestinal upset if consumed. Contact with sap may also cause mild dermatitis in sensitive individuals. In Australia, English ivy can become invasive, particularly in temperate and high-rainfall regions, spreading as a dense groundcover and climbing trees and structures using aerial roots.
Wear gloves, long sleeves and eye protection when handling ivy, particularly if cutting overhead growth. For climbing ivy, cut all stems at the base using sharp secateurs or a pruning saw. Leave upper growth in place to die back naturally rather than pulling it down immediately, which can damage bark or structures. Once the foliage has browned and loosened, it can be carefully removed. For groundcover infestations, lift and roll sections back using a garden fork or mattock, removing as much root material as possible.
Australian native alternatives
Purple coral pea (Hardenbergia violacea) in temperate climates, offering vigorous climbing growth and rich purple flowers suited to sunny positions with well-drained soil.
Bower vine (Pandorea jasminoides) in subtropical regions, producing soft glossy foliage and trumpet-shaped blooms ideal for fences and pergolas in warm humid conditions.
Native clematis (Clematis aristata) in cool temperate areas, providing twining growth and star-like flowers that thrive in woodland gardens with sheltered roots and sunlit tops. Note that this species is sometimes called old man's beard — a name also applied to the invasive Clematis vitalba. Native clematis is a well-behaved Australian species and the two should not be confused.
8. Arum lily (Zantedeschia aethiopica)
Arum lily is native to southern Africa, where it grows in moist grasslands and along waterways. It contains calcium oxalate crystals within its leaves and stems — microscopic needle-like structures that act as a defence mechanism, deterring herbivores by causing intense irritation if chewed or ingested. Contact with sap can irritate skin and ingestion may cause burning of the mouth, swelling and gastrointestinal upset in pets and livestock.
Wear gloves, long sleeves and sturdy footwear when removing arum lily, especially in wet or boggy conditions. Use a garden fork or spade to loosen soil and carefully lift the rhizomes. Work methodically, as even small fragments can reshoot. In heavy clay or waterlogged soils, removal can be labour-intensive and may require repeated efforts over time.
Australian native alternatives
Native iris (Patersonia species) in well-drained soils, producing upright sword-like foliage and delicate purple to blue flowers suited to sunny open positions.
Gymea lily (Doryanthes excelsa) in temperate to subtropical climates, producing dramatic tall flower spikes that create strong architectural impact in large garden spaces.
Native ferns (various Australian genera) in shaded damp areas, providing lush textured foliage adapted to protected understorey conditions with consistent moisture.
9. Pencil tree (Euphorbia tirucalli)
Pencil tree is native to eastern and southern Africa, where it evolved in dry, open landscapes exposed to grazing pressure. Like many members of the Euphorbia genus, it produces a milky latex sap as a chemical defence. This sap deters herbivores and seals damaged tissue in arid environments. The latex can cause significant skin irritation and, if it comes into contact with the eyes, may result in severe pain. Ingestion can cause gastrointestinal distress in pets.
Wear thick gloves, long sleeves, long trousers and eye protection before cutting. Avoid working on windy days, as sap can flick or splatter when stems are cut. Use sharp secateurs or loppers to remove stems in manageable sections. Allow cut ends to dry before further handling to reduce sap exposure. For established plants, dig out the root mass with a spade, taking care to avoid snapping stems near your face. Wash hands, tools and any exposed skin thoroughly after handling.
Australian native alternatives
Silver cassia (Senna artemisioides) in arid and semi-arid climates, offering fine-textured silver foliage and bright yellow flowers adapted to low rainfall and poor soils.
Slender rice flower (Ozothamnus diosmifolius) in temperate climates, forming upright narrow stems with fine foliage and clustered flower heads that create a light architectural screen.
River tea tree (Leptospermum brachyandrum) in warm temperate to subtropical climates, offering slender weeping branchlets and fine-textured foliage suited to sunny, well-drained positions.
Ian McMaster, CC BY 3.0, via Wikimedia Commons
10. True lily (Lilium spp.)
True lilies originate from Europe, Asia and North America. In their native habitats they evolved chemical compounds to deter grazing animals and insect damage. While many ornamental plants contain mild toxins, lilies are notable for their extreme toxicity to cats. All parts of the plant are dangerous to cats, including leaves, petals, stems, pollen and even water from a vase containing cut flowers. Ingestion of small amounts can cause acute kidney failure.
If pets are present, remove flowering stems promptly. Use sharp secateurs to cut stems at the base and carefully collect fallen petals and visible pollen. Dig out bulbs completely using a garden fork, as remaining bulb fragments can reshoot. Wear gloves when handling plant material and wash hands and tools afterwards.
Australian native alternatives
Vanilla lily (Arthropodium species) in temperate climates, producing soft strappy foliage and delicate star-like flowers suited to well-drained soils and part shade.
Blue flax lily (Dianella caerulea) in coastal and temperate regions, offering fine foliage and airy flowering stems suited to low-maintenance native plantings.
Fringe lily (Thysanotus species) in warm, well-drained soils, delivering fine-textured foliage and distinctive fringed blooms adapted to open sunny positions.
Resilience is built into local plants
Many of these ornamentals persist because they are hardy, fast-growing and widely available. Some have spread beyond garden fences and become invasive in parts of Australia. Their toughness comes from chemical defence — compounds that helped them survive grazing and harsh conditions in their native habitats.
But resilience built on toxicity is not always what we want in a garden shared with pets, wildlife and children.
Choosing locally appropriate native species reduces unnecessary risk, strengthens habitat value and supports pollinators, birds and small mammals. It also creates gardens that function more naturally within Australian ecosystems — drawing on plants that evolved here and belong here. Our guide to native plants for beginners is a practical starting point for making the shift.
keep reading
A Guide to Australian Native Gardening
How to plan, plant and care for a thriving native garden, whatever your experience level.
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