Poisonous plants

Do you know what poisonous plants are lurking in your backyard or paddocks? Most people are totally unaware of what plants are poisonous to their grazing livestock (cattle, sheep, goats, deer, alpaca, llama etc.). We’ve compiled a list below of some of these poisonous plants and clinical signs which may be associated with toxicity.

When do plants cause toxicity?

For most of these poisonous plants, toxicity only occurs when the plant or parts of it are ingested. Often animals avoid these plants, however there are times when they may not. Animals may eat these plants when they are short of their normal feed supply (grass, hay), when parts of the plant fall into their grazing area (nuts, seeds, fruit, leaves, etc.) or when cut branches begin to wilt (the wilting makes them particularly appealing and tasty!)

Clinical signs of toxicity

Vets often use the term ‘clinical signs’ which simply means symptoms displayed by animals. Clinical signs will vary depending what plant has been eaten, how much of it is eaten, and the animal’s immune response. Clinical signs may be immediate or delayed by up to 24-48 hours after being eaten.

Clinical signs can vary from mild to severe including:

  • Diarrhoea
  • Lack of appetite and/or abdominal pain
  • Staggering and muscle weakness
  • Hypersalivation and drooling / nasal discharge
  • Vomiting and/or frothing at the mouth
  • Convulsions or tremors
  • Difficulty breathing or swallowing
  • Paralysis
  • Organ damage
  • Sudden death


Poisonous shrubs and other plants

Arum lily, bracken fern, foxglove, goats rue, hemlock, ragwort, stinging nettle, solanum species (potatoes, poro poro, black nightshade).

Poisonous trees

Karaka, kowhai, macrocarpa, ngaio, oleander, rhododendron, tutu, yew.

This is not a full list, just some of the common plants seen – there are more not listed here.


Key tips

  • Pull out weeds from paddocks and avoid planting shrubs within the animals grazing reach
  • Do not feed branches and leaves cut or fallen from trees or bushes
  • If you think your animal may be displaying signs of toxicity call your vet immediately