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Keeping Pets Safe in the Garden

Many pets enjoy exploring garden foliage and scents. Unfortunately, the curious nature of pets can sometimes get them into trouble. A seemingly innocuous flowerbed or vegetable patch can be poisonous to cats and dogs. Owners can help their furry friends avoid danger by limiting the number of hazards and, what's more important, by supervising animals' outdoor activities.

Oakville, Ontario, veterinarian Dr. Wolfgang Zenker, DVM, M.Sc. (Path), MBA, says that an owner suspecting that a dog or cat has ingested a toxic substance should take the pet to the veterinarian immediately. "A veterinarian can easily induce vomiting within half an hour of ingestion of a poison", he says. "Time is of the essence—don't delay!" Dr. Zenker also points out that owners should remember that most dogs and cats are much smaller than humans, and a seemingly small amount of toxin can create a serious problem for them.

When it comes to creating an outdoor area that's pet safe, every gardener should be aware of the following.


Harmful Plants

Plant Name

Toxic Effects on Cats and Dogs

(Lilium spp.)


Toxin: unknown.


Highly toxic to cats—ingestion of small amounts can cause severe kidney damage.


Castor bean
(Ricinus communis)


Toxin: ricin.


Seeds are highly toxic, but all parts of plant are poisonous.


Ingestion symptoms include abdominal pain, drooling, vomiting, diarrhea, weakness, loss of appetite and excessive thirst. Severe cases can result in death.


(Chrysanthemum spp.)


Toxin: pyrethrins (also found in insecticides).


Ingestion symptoms include vomiting, diarrhea, hypersalivation, dermatitis and lack of coordination.


Plant Name

Toxic Effects on Cats and Dogs

Tulip (Tulipa spp.), daffodil (Narcissus spp.), hyacinth (Hyacinthus orientalis)


Toxin: alkaloids and tulipalin A and B (in tulips).


Bulbs are most toxic part of plant.


Ingestion symptoms include vomiting and diarrhea; large amounts can cause low blood pressure, cardiac arrhythmia and tremors.


Malus spp. (apple trees and shrubs) and Prunus spp. (cherry, plum, peach, almond, apricot)


Toxin: cyanogenic glycosides.


Stems, leaves and seeds are toxic, especially when wilting.


Ingestion symptoms include brick-red mucous membranes, dilated pupils, difficulty breathing, panting and shock.


Plantain lily
(Hosta plataginea)


Toxin: saponins.


Ingestion symptoms include vomiting, diarrhea and depression.


(Begonia spp.)


Toxin: insoluble oxalates.


Ingestion symptoms include oral irritation, drooling, vomiting and difficulty swallowing.


(Pelargonium spp.)


Toxin: geraniol, linalool.

Ingestion symptoms include vomiting, anorexia, depression and dermatitis.


(Rhododendron spp.)


Toxin: grayantoxin


Leaves and nectar are highly toxic.


Ingestion symptoms include vomiting, diarrhea, low blood pressure, coma, central nervous system depression, cardiovascular collapse and death.


(Rheum rhabarbarum)


Toxin: soluble calcium oxalates.


Ingestion symptoms include kidney failure, tremors and salivation.


Other toxic plants include peony (Paeonis officinalis), primrose (Primula vulgaris), foxglove (Digitalis purpurea), morning glory (Ipomoea spp.), western bleeding heart (Dicentra formosa), clematis, lily of the valley (Convallaria majalis), lantana, iris, yarrow (Achillea millefolium), oleander, onion (Allium cepa) and garlic (Allium sativum). Ask your veterinarian for a complete list of toxic plants. 

While even this condensed list may seem extensive, there are a number of non-toxic plants pet owners can grow. These include alyssum, pot marigold (Calendula officinalis), impatiens (Impatiens spp.), petunia, zinnia, bachelor's button (Centaurea cyanus), hens and chicks (Echeveria elegans), tickseed (Coreopsis californica), common snapdragon (Antirrhinum majus), gerber daisy (Gerbera jamesonii), hollyhock (Althea rosea), cucumber (Cucumis sativus), beet (Beta vulgaris) and zucchini (Cucurbita pepo).

Chemical Dangers: Fertilizers, Herbicides, Insecticides and Others
Sometimes garden preparation and maintenance products include chemicals that can be harmful if pets ingest them. When applying fertilizers or herbicides to the lawn or garden, it's best to keep pets away from the locale for several days. When walking through a treated area, pets can come in contact with the chemicals and become ill from licking the residue off their paws.

Pet owners may want to assess how inconvenient a pest is relative to the treatment required. "Understanding the pest and following the instructions on the product label...will help decrease risk [to pets]", says Martha Hoff of Colorado State University's master gardener program. If a pesticide is warranted, it should be used in areas that are out of a pet's reach. A dog or cat that has ingested pesticide may be lethargic and experience vomiting, tremors or convulsions.

Rodenticides are designed to taste good to rodents, making them of interest to cats and dogs as well. Anticoagulants, which function by inhibiting blood-clotting factors, are the most commonly used. Rodenticide poisoning in cats and dogs may present with the following symptoms: anemia, blood in the urine, internal bleeding, weakness, lack of coordination and rapid, shallow breathing.

The most common pet poisoning Dr. Zenker sees is caused by the ingestion of slug bait. Metaldehyde, a common component of slug and snail bait, causes apprehensiveness, lack of coordination, tremors, increased heart and respiratory rate and convulsions. Less toxic alternatives exist, such as placing copper barrier strips around plants.

An important part of poison prevention is proper chemical storage. Ensure that all harmful toxins are safely stored away in a shed or garage. It's vital to keep chemicals in their original containers; this will ensure that product toxicology information is available should an emergency arise. Take the product packaging with you to the veterinarian's office, and remember Dr. Zenker's wise words—don't delay!

Water Hazards
Water features are popular in many gardens, but they can pose a risk to pets. Ponds and pools present drowning dangers that can be avoided by supervising a pet's playtime or by creating a barrier to the water. Pools, ponds and hot tubs may all require special water treatment chemicals. These should be used according to directions and always stored safely.

Other Things to Watch for Around the Yard

  • Mulches can be a pet danger if ingested. Avoid using cocoa-bean mulch, which contains the same harmful chemical as chocolate. Dogs that like to eat rocks should be supervised when around landscaping stone. A dog trainer or veterinarian can help modify behavior to eliminate this problem.
  • Compost can smell delightful to a dog; it should be contained in a pet-proof structure.
  • Summertime barbecues are a treat, but it's important to keep matches and lighter fluid away from pets.
  • Sometimes other animals can be troublesome to pets, including stinging insects, mosquitoes or biting flies. Pet owners can talk to a veterinarian about treatments for stings and about methods for deterring biting insects from bothering pets. A hopping toad is hard for a cat or dog to resist, but touching, catching or eating these animals must be discouraged. Toads are toxic, and the ingestion symptoms can range from frothing at the mouth to convulsions and death.


While there are many dog and cat dangers in the garden, enjoying a safe summer with your pet isn't impossible. Careful supervision and some basic preventive measures can greatly reduce a pet's risk of harm. If a pet does get into trouble, or if a pet owner suspects a problem, timing is critical. Don't delay—consult a veterinarian right away.



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