Tropical Gardening Helpline: Some plants toxic to animals

  • Cats should be kept away from plants that are toxic to them. (Photo courtesy /
  • Though pets are not harmed by eating grass, many other plants can be toxic to them. (Photo courtesy /
  • Keeping your dogs and cats away from toxic plants will help preserve their good health. (Photo courtesy /

Bonnie asks: I am hoping you can let your readers know that macadamia nuts are toxic to dogs so that they don’t have to experience a really sick dog without knowing the cause.

Tropical Gardener Answer: It is true that many plants that we grow are toxic to our pets. Check out which plants are toxic to pets at either or I will identify some of the plants we often grow here for your information.


Macadamia nuts are very toxic to dogs. If they eat them, they may vomit or become weak and in some cases they may lose control of their hind legs. The symptoms may take as much as 12 hours after consumption of the nuts to appear. They should diminish and disappear within 72 hours. Those can be very scary hours unless you know your dog has eaten mac nuts. Dogs are also capable of cracking macnut shells in their teeth which can also cause harm if they swallow the sharp shells.

Cacao beans are toxic to both dogs and cats. Commercial chocolate in small amounts can cause distress and vomiting in pets. Cacao beans are 100% chocolate, however, and in sufficient quantities can be deadly. It’s important to make sure cacao pods and beans are inaccessible to pets. Though our bodies can handle the theobromine in chocolate, pets bodies struggle to process it. Chocolate increases urination and affects the central nervous system as well as the heart muscle. Consuming cacao beans can lead to convulsions, muscle tremors, seizures, coma and even death. It is also important to avoid using cacao hulls for mulch if you have pets. Consumption of the concentrated theobromide in the hulls can cause death from cardiac arrest.

If you are growing aloe, make sure to keep it away from your pets. It is toxic to both cats and dogs. If they eat it, the symptoms of a toxic reaction include: vomiting, depression, diarrhea and tremors.

Dieffenbachia, also known as “dumb cane,” is a common garden and house plant here. Its consumption by pets can cause oral irritation, vomiting, and difficulty swallowing. It can also create a burning sensation of the lips, tongue, and mouth. A milder version of these same symptoms can occur when people eat dieffenbachia leaves. Though not deadly, the results of eating dieffenbachia leaves is very unpleasant.

The Sago Palm is an extremely poisonous plant to dogs and cats. If any part of the plant is ingested, bloody vomiting and diarrhea, bleeding disorders, liver failure and sometimes death can occur.

Oleander is a flowering shrub often used for hedges here. It is toxic to dogs, cats and people who eat any part of it. It can cause fatal heart abnormalities, muscle tremors, incoordination, vomiting and bloody diarrhea. Do not eat.

This is just a brief list of plants that you should try to keep away from your pets. Don’t stop growing them, just be aware of the dangers they pose and take precautions to prevent your cats and dogs from consuming them.

Email plant questions to for answers by Certified Master Gardeners. Some questions will be chosen for inclusion in this column.

Diana Duff is a plant adviser, educator and consultant living in a dryland forest north of Kailua-Kona.

Gardening Events

Saturday: “Work Day at Amy Greenwell Garden” from 9 a.m. to 12:30 p.m. Meet at the Garden Visitor Center across from the Manago Hotel in Captain Cook. Volunteers will be able to help with garden maintenance and are invited to bring a brown bag lunch. Water and snacks provided. Call Peter at 323-3318 for more information.

Farmer Direct Markets

Wednesday: “Hooulu Farmers Market” 9 a.m. to 2 p.m. at Sheraton Kona Resort &Spa at Keauhou Bay

Saturday: “Keauhou Farmers Market” 8 a.m. to noon at Keauhou Shopping Center

“Kamuela Farmer’s Market” from 7 a.m. to noon at Pukalani Stables

“Waimea Town Market” from 7:30 a.m. to noon at the Parker School in central Waimea

“Waimea Homestead Farmers Market” from 7 a.m. to noon next to Thelma Parker Gym in front of Thelma Parker Library.

Sunday: “Pure Kona Green Market” 9 a.m. – 2 p.m. at Amy Greenwell Garden in Captain Cook

“Hamakua Harvest” 9 a.m. to 2 p.m. at Highway 19 and Mamane Street in Honokaa

Plant Advice Lines



Tuesdays and Thursdays: 9 a.m. to noon at UH-CES in Kainaliu – 322-4892

Mon., Tues. and Fri: 9 a.m. to noon at UH CES at Komohana in Hilo 981-5199 or

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