We are not familiar with any harmful or poisonous effects of red-tipped photinia. However, the shrub is classified as “invasive” in several states. Invasive means that the shrub can “escape” the area where it was planted, with the potential to displace native shrubs, trees, and other vegetation. Also, several university Web sites state that red-tipped photinia is susceptible to diseases, insects, and root issues.
When choosing shrubs and/or trees to place in or near a horse pasture, avoid the following, which have been identified as poisonous or harmful:
1. All cherry species
2. Black locust
3. Dogbane
4. Oak (immature leaves and acorns)
5. Oleander
6. Yew
7. Maple (wilted leaves only)
8. Black walnut (shavings and possibly immature nuts)
9. Rhododendron.
For more information on plants poisonous or harmful to horses, go to www.extension.umn.edu/horse and see the publication “Plants Poisonous or Harmful to Horses in the North Central United States.” Cornell University also has a good Web site for researching poisonous or harmful plants (www.ansci.cornell.edu/plants/alphalist.html).