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Q. Who is Mr. Smarty Plants?

A: There are those who suspect Wildflower Center volunteers are the culpable and capable culprits. Yet, others think staff members play some, albeit small, role. You can torture us with your plant questions, but we will never reveal the Green Guru's secret identity.

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Ask Mr. Smarty Plants is a free service provided by the staff and volunteers at the Lady Bird Johnson Wildflower Center.

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Tuesday - June 02, 2009

From: Americus, GA
Region: Southeast
Topic: Poisonous Plants
Title: Are Cleveland Pear trees in Georgia toxic to horses and/ or dogs?
Answered by: Jimmy Mills

QUESTION:

Are flowering Cleveland Pear trees (Pyrus calleryana) poisonous to horses and/or dogs? I have read that the prunus species are, does that include pear trees? Please help!

ANSWER:

It is true that members of the genus Prunus (Plums, Peaches, Apricots, and Cherries) can be toxic. The toxic compounds are cyanogenic glycosides (chemicals that are converted to cyanide or prussic acid when eaten). The compounds are mostly in the leaves and in the seed. Apples (genus Malus) also contain these compounds, but  I had not seen pears (genus Pyrus) being  listed as containing the glycosides until i saw this article from the Kitsap Conservation District in Washington state. The compounds are more concentrated in wilted leaves than in fresh leaves.

I have included a list of databases of toxic plants that will allow you to learn what other plants to look out for.

Cornell University Plants Poisonous to Livestock

Universtiy of Pennsylvania's Poisonous Plants Database

Poisonous Plants of North Carolina

Texas Toxic Plant Database

Additionally, here are databases that are specific for plants poisonous to horses.

Equisearch.com

ASPCA

Ohio State University

To search the lists, I recommend using the scientific name since those names are generally standard, whereas the common names often vary in spelling and usage. 

Since the Lady Bird Johnson Wildflower Center is committed to the care and propagation of plants native not only to North America but to the area in which they are being grown, I would be remiss not to point out that Pyrus calleryana is a non-native plant (introduced from Asia) and is considered an invasive species in some parts of the country.

 

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