San Antonio Express News
Sunday, July 3, 2005

By Dr. Jerry Parsons

My brother Lynn, a surgeon in Ohio, sent me a website: http://www.uexplore.com/health/poisonplants.htm which lists plants poisonous to dogs. Sadly enough, the A&M site at: http://aggie-horticulture.tamu.edu/plant answers/publications/poison/poison.html and a Purdue University School of Veterinary Medicine at: http://www.vet.purdue.edu/depts/addl/toxic/navigate.htm are listed as: Additional Sources of Information. I say “sadly enough” because of the anguish such lists cause to people who love their pets dearly. After seeing these sites and listings, they will be discontent for the rest of their pet’s life while trying to protect the dear darlings from common plants which could possibly harm their loved one but seldom, if ever, does.

Plants listed in the Purdue Veterinary Medicine site and listed as “Extremely Toxic” are: Castor bean (Causes nausea, vomiting, diarrhea, intestinal colic, thirst, convulsions, may be fatal), Cocklebur, Pigweed, Johnsongrass, and Oleander.

The “Moderately Toxic” listing includes: Bulbs, Lupine (Bluebonnets!), Rhubarb, Azalea, Rhododendron, Oats, Larkspur, Milkweed, Mustard, Spurges, Nightshades, Black Walnut, and Red Oak.

The “Minimally Toxic” plants listed include: English Ivy, Catnip, Poinsettia (Euphorbia pulcherrima )-the Christmas Plant — all parts cause burning in the mouth and throat, vomiting, diarrhea, intestinal irritation; Stinging Nettle, Marijuana, St. Johnswort, Pokeweed, and Bouncing Bet.

Plants listed as toxic to ALL animals are: Bulbs, Rhubarb, Azalea (Causes vomiting, muscle weakness, breathing difficulty; heart depressant and may be fatal.), Rhododendron, Castor bean, Milkweed, Stinging Nettle, Cocklebur, Marijuana, Pokeweed, Bouncing Bet, Nightshades, Red Oak, Yew, and Oleander.

So why would anyone recommend that you plant a poisonous plant in your landscape? The answer is simple; if we could only recommend non poisonous plants, we would have nothing to recommend! New Gold lantana is a good example. The “New Gold” lantana is a beautifully blooming, drought tolerant, pest resistant plant. However, the entire lantana plant group is reported as poisonous. Lantana is reported to be especially poisonous to cattle and sheep though usually not browsed by them. Symptoms of lantana poisoning include sluggishness, partial paralysis and bloody diarrhea (sounds like a bad Friday night fling to me!). In addition to gastro-intestinal irritants, this plant contains a substance that will cause photosensitization. Photosensitivity is that condition in animals characterized by hyper reaction to sunlight. Cattle, horses, sheep, goats and swine are susceptible to photosensitization.
It is not that I am skeptical, but I have seen many pets living around most of the plants listed above and HAVE NEVER had one of the little darlings decide to commit suicide or diarrhea-cide by eating a landscape plant. Maybe I am just too naive and just don’t know any better, so I am asking for your help. PLEASE, please, if you have ever had a pet killed, made sick or even caused to have that lovely bloody diarrhea-or if you have ever heard (not from the veterinarian’s office!!) of ANY pet being poisoned by plants, please e-mail me the details at: jerryparsons@tamu.edu. Or telephone me on the Milberger’s Garden Show on Saturdays from 12:00 p.m. to 2:00 p.m. and Sundays from 12:00 p.m. to 2:00 p.m. on KLUP Radio (AM 930) at: 210-308 8867 or Toll Free 1 866 308 8867.

If you want to read this entire column with color images included and the listing of cold-blooded, plant “killers” of children, see the first column for July, 2005, at: http://www.plantanswers.com/garden_columns .htm entitled: “???POISONOUS PLANTS.???.” After we get the pet scam worked out, we may talk about how many children have been poisoned by plants in the U.S. in the last, say, 100 years!!!

Dr. Jerry Parsons is a Professor for Texas A&M University and a Texas Cooperative Extension Horticulturist for over 30 years in South Central Texas. For more information on this or other horticulture topics, go to www.plantanswers.com and our County Extension website at http://bexar-tx.tamu.edu.


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