Skip to main content

"Poisonous" does not mean deadly. Some manifestations of toxicity are subtle. The dose, as always, determines if a plant is safe source of nutrients or a toxic hazard.

Frequently (and not so frequently) Asked Questions

Simple keyword search (one or two words only)


BRIEF: Why are alfalfa and Tall fescue on the list of poisonous plants?

I was trying to look up Poisonous plants for horses. On this list Alfalfa and Tall Fescue are listed and I know horses eat these. why are they on this list? I was also wondering if either Crepe Myrtle or Bradford Pear trees are poisonous to horses.


Fresh alfalfa pasture can cause bloating in cattle and some say that when frozen, can cause problems for horses, too. At any rate, a diet made up of only pure alfalfa has far too much protein and calcium for any but the fastest growing and most pregnant of horses anyway. Tall fescue has a variety of toxins derived from both endophytic fungi and perhaps some parasitic ones that interfere with thermoregulation and reproduction. This is widely known, stockmen use it anyway and watch out for signs of too much in too hot weather. They have also bred endophyte varieties. Bradford pears are not good because the leaves contain cyanide. I don't know about Crepe myrtle.