The KPRC Radio Gardenline Tip By Randy Lemmon For 02-24-05 Printer-Friendly Version



Some Plants Are Poisonous To Pets -- But Don't Overreact...

As promised, following the Channel 2 Sago-Bashing Story from two weeks ago, I would put a list on our email tips/website that had a more horticurally-responsible angle. Before we get into the Toxicity issue, I received a couple of emails from listeners who asked for a tropical alternative that wasn't quite as toxic, if they just wanted to play it safe. The two best ideas I could come up with as replacments were Pygmy Date Palms and Windmill Palms.

The first thing to remember is that not all dogs and cats are susceptible to the most poisonous plants listed below. Some breeds just have a built-in resistance. It's also important to note that most animals have a built-in ability to avoid that which is poisonous -- a sort of genetic code capable of instinctively avoiding that which is poisonous.

But then there are those dogs (and in some cases very few cats) that will just eat and chew anything and everything, and so a plant is fair game. But the most important thing to keep in mind, is that the smaller the breed (such as the Yorkie or the Dachsund profiled in the TV story) the toxicity levels are obviously more intense, and as such should probably be avoided all together. I've had big dogs for years, and I've had many of the plants listed below without any adverse problems. But since the most poisonous part of the Sago is the seed (AND IT'S WORTH NOTING, THAT NOT ALL SAGO PALMS PRODUCE SEEDS, NOT SOMETHING THE TV STORY WAS WILLING TO EXPOSE) avoid planting them in the landscape if you have small animals that are allowed to be outdoors. Or keep an eye out for the sago seeds, and harvest them out before they ever get to the ground. While technically the whole plant is listed as poisonous, it is almost impossible for dogs to eat any part of an established Sago, because the fronds will poke the heck out of them.

Now, having said all that, it is also worth noting that since all parts of a Sago are technically poisonous, that means the pups/sports are poisonous too. And since the pups/sports are so soft when they first come out, don't let them be available to any curious dog/cat. However, most pups/sports from Sagos are so far under the frond canopy, this is usually never an issue worth worrying too much about. During our interviews/conversations with the true Sago experts (Lynn McHamey with www.sagopalms.com and Greg Meiser with www.texasriviera.com) and Toxicolgy expert with Texas A&M's Veterinary Diagnostic Lab (Dr. Catherine Barr), here is what Dr. Barr provided the GardenLine listener with.

From the Diagnostic Toxicologist’s viewpoint, the top ten poisonous plants for dogs and cats in the Houston Metro area are listed below, with notes about symptoms to watch for in your animals in the top 3 offenders. [For information on plants toxic to ruminants and horses, please see the web site, < http://tvmdlweb.tamu.edu > ]

If Randy hasn’t pounded you with it before, Latin names are critical when trying to identify toxic plants. The common names for these plants change radically from region to region and from grandmother to grandmother – if you can tell me what the nurseryman’s label called the plant, I can tell you if it’s toxic and what it can do.

It is always important with these plants to remember that they only pose a true threat if they are readily available to the pet. Plants in pots in sequestered areas, pots above reach in the house, and low fence-type borders around dangerous shrubs may solve some problems on your own property. Walking your pet on a leash and keeping and eye on where they are will help prevent access to potentially hazardous plants in neighbors’ yards.

The amount of plant material consumed and body weight of the animal determine whether a plant will poison that individual. These plants have made the top-ten list because they contain high levels of toxin, and small amounts will poison any animal.

Now, beginning with the most toxic, here’s that list:
Oleander (Nerium oleander) All parts are toxic. The toxins are a series of cardenolide cardiac glycosides including oleandrin (for which we have a test). The plant works very much like digoxin (Cardoxin®, Lanoxin®) causing sudden changes in heart rhythm – usually slowing it but also causing odd rhythms. It also has irritant properties that cause vomiting and diarrhea. As little as 0.005 % of an animal’s body weight can be fatal within hours. That’s less than 2 leaves per Great Dane.Sago palm, leatherleaf palm (Cycas sp.) The seeds and root are more toxic than the leaves. The toxins include cycasin, neocycasin A & B, microzamin, BMAA, and cycasin metabolite methylazoxymethanol (MAM). A few bites causes violent vomiting and diarrhea in dogs, followed by liver failure which often shows itself as drunken behavior followed by seizures, coma and death within 1-3 days.

Lantana (Lantana camara) The entire plant is toxic, but the green berries are the worst. The toxins are pentacyclic triterpenes lantadene A & B. Dogs that eat enough leaves or even gnaw on the bare sticks in the winter can vomit and have diarrhea due to gut irritation. If the dose is low, that’s all. If it is too high, they continue with liver effects resulting in weakness, drunken behavior, depression, and jaundice (yellow pigment in the gums and the whites of the eyes), and eventually coma and death. The time between eating the plant and death is 3-5 days without veterinary intervention.

Mushrooms – Green Gills (Chlorophyllum sp.) and Amanitas

Lilies -- espcially the flower and specifically toxic to cats

Azaleas (Rhododendron)

Kalanchoe (Kalanchoe)

Chinaberry (Melia azederach)

Jerusalem cherry (Solanum pseudocapsicum)

Yessterday-today-and-Tomorrow (Brunfelsia calycina)

Until next issue, here's to Great Gardening from the GardenLine, heard exclusively weekend mornings from 8 to noon on Talkradio 950 KPRC.