Toxic Plants for dogs

It’s important to check that the plants your dog encounters in and around your home are safe, as there are many plants that are toxic to them. When out for walks, don’t allow your dog to chew on them or any other plants you are unfamiliar with.

Below are ten common plants (and plant-like organisms) that are moderately to highly toxic to dogs you should watch out for. However, it’s important to note that this list is not exhaustive.

1. Mushrooms

Mushroom species are very difficult to identify, as they vary in appearance and colour during different stages of growth. Many toxic mushrooms are similar in appearance to your average store-bought mushroom. This is why it is never recommended to eat wild picked mushrooms. Poisonous mushroom species are toxic to dogs and people.

Signs of mushroom toxicity

The effects of eating poisonous mushrooms varies depending on the species consumed. Signs of toxicity can present anywhere from 15 minutes to many days later.

Neurological signs

Toxins affecting the neurological system often present the quickest, usually within 15- 90 minutes of consumption, but it can be hours before signs appear. Signs vary from weakness, unsteadiness, tremors, and seizures through to disorientation, hallucinations, vocalisation, lethargy, and agitation, seen more commonly with psilocybin “magic” mushrooms.

Gastrointestinal signs

Many species of mushrooms will cause gastrointestinal signs and/or additional effects. Signs include:

• Vomiting
• Diarrhoea
• Inappetence
• Excessive drooling

Liver disease signs

Generally, mushrooms that cause liver disease (including the death cap mushroom) will first cause gastrointestinal signs 6-12hrs after ingestion and then progress to liver failure soon after. Consumption of severely poisonous mushroom cases can lead to death after 1-2 days.

Kidney disease signs

There are fewer mushroom species that directly affect the kidneys, though some do exist. Like mushrooms that affect the liver, the first signs of toxicity generally start to present within 6-12hrs, then more serious effects develop within the following days to week. Signs of kidney damage include:

• Excessive thirst and urination
• Vomiting
• Inappetence
• Dehydration

2. Blue-Green Algae

Blue-green algae is a type of cyanobacteria found in fresh and brackish water. Large amounts can aggregate on the water’s surface. Dogs become ill from swimming in or drinking water contaminated by blue-green algae.

Many different types of toxins may be present in algal blooms. They can cause effects to the liver, skin, and even the central nervous system.

Signs of blue-green algae toxicity

Signs of blue-green algae toxicity include:

• Vomiting
• Diarrhoea
• Drooling
• Weakness
• Itchy skin
• Blisters
• Respiratory distress
• Tremors
• Seizures

Liver failure is also a possible consequence of blue-green algae ingestion

3. Daffodils, Hyacinths and Tulips

Daffodils, hyacinths, and tulips are poisonous to dogs and cats. While all parts of these plants are poisonous, the bulb is the most toxic part. Dogs are at higher risk of being exposed to the most toxic parts because, unlike cats, they’re more likely to dig up bulbs in the garden bed.

Daffodils contain multiple toxic components including oxalate crystals, alkaloids (especially lycorine) and glycosides. Hyacinths and tulips belong to the Liliaceae family and contain allergenic lactones or similar alkaloids.

Signs of daffodil, hyacinth, and tulip toxicities

Ingestion of a small amount of the plant may only cause minor symptoms including irritation to the skin, mouth, and throat, as well as digestive symptoms such as drooling, vomiting, and diarrhoea.

If larger amounts are ingested (especially the bulb), this can cause convulsions, tremors, changes to respiration, difficulty breathing, elevated heart rate, and heart arrhythmias.

4. Cycads/Sago palms

Sago palms are small, bush-sized palm trees. They and other cycad species are commonly found in gardens, and are highly toxic to dogs and cats. The seed is the most toxic part, but all parts of the plant are poisonous.

Cycads contain a toxin called cycasin, which is broken down in the gut into a toxic component methylazoxymethanol, which is responsible for most of the toxic effects seen. Toxicity results in severe liver damage and failure. Ingestion of even small quantities can result in severe poisoning and death.

Signs of cycad toxicity

Signs of cycad toxicity include:

• Abdominal pain
• Vomiting
• Diarrhoea
• Weakness
• Lethargy
• Seizures
• Coma
• Death

5. Oleander

Oleander is an outdoor shrub with delicate white and pink flowers that is highly toxic to dogs and cats. All parts of the plant are toxic. Even the water in the plant base can contain toxic components.

This plant contains naturally occurring toxins from a group called cardiac glycoside toxins. These toxins primarily affect the heart.

Signs of oleander toxicity

Signs your dog has consumed oleander include:

• Cardiovascular signs – abnormal heart rate and rhythm, weakness, respiratory changes
• Gastrointestinal signs – vomiting, drooling
• Neurological signs – tremors, seizures

6. Azaleas

Azaleas are one of over 1000 species of rhododendron. These small shrubs that are less toxic than some of the larger rhododendron species but are still poisonous to dogs if ingested. All parts of the plant are toxic. Only a small amount of the plant needs to be consumed for poisoning to occur.

These plants contain grayanotoxins, which affect the skeletal and heart muscles.

Signs of azalea toxicity

Symptoms of azalea toxicity include:

• Gastrointestinal signs – drooling, vomiting, diarrhoea, inappetence and abdominal pain
• Cardiovascular signs – abnormal heart rate, arrhythmias, weakness, low blood pressure
• Neurological signs – depression, tremors, transient blindness and seizures

7. Autumn Crocus

Autumn crocus is a popular house and yard plant. All parts of the plant are considered toxic.

It contains colchicine and other alkaloids and can cause significant illness in dogs, including multi-organ damage and bone marrow suppression.

Signs of autumn crocus toxicity

Signs of autumn crocus toxicity include:

• Bloody vomiting
• Diarrhoea
• Signs of shock, such as abnormal breathing pattern, abnormal heart rate, pale gums, and lethargy.

8. Lantana

Considered a weed in Australia, this colourful, flowering shrub is part of the Verbenaceae family and is extremely toxic to cats and dogs. It contains pentacyclic triterpenoids, which can cause liver failure; however, this is more common in livestock than dogs and cats.

Signs of lantana toxicity

Signs your dog has eaten lantana include:

• Vomiting
• Diarrhoea
• Inappetence
• Weakness
• Laboured breathing

9. Philodendrons

There are many species of philodendron. Though usually less dangerous than many plants listed here, it does still cause significant irritation if chewed on and can have some serious side effects after ingestion.

This plant contains oxalate crystals. When chewed or bitten, the oxalate crystals are released, causing oral and gastrointestinal irritation and inflammation.

Signs of philodendron toxicity

Signs your dog has bitten a philodendron include:

• Drooling
• Pawing at the mouth
• Oral pain
• Decreased appetite
• Vomiting
• Swelling of the upper airways (in rare cases)

10. Yew

This is a common evergreen shrub that is extremely poisonous to all animals. All parts of the plant are very poisonous, including the red berries.

Yew contains taxines which, when ingested by dogs and cats, can cause serious illness and potentially death.

Signs of yew toxicity

Signs of yew toxicity include:

• Drooling
• Difficulty breathing
• Severe changes to heart rate and blood pressure
• Dilated pupils
• Tremors
• Seizures
• Coma