The following is from a phamplet put out by the University of Florida called
"Plants That Poison Farm Animals"
Common Oleander:
Toxicity: Two toxic glucosides with properties similar to those of the
digitalis glucosides have bee isolated from oleander. Cases of poisoning have
been reported in all classes of livestock, as well as in humans.
Approximately 15 to 20 grams of the green leaves are sufficient to induce
death in mature cattle and horses. The dry leaves are almost as toxic as the
green ones.
Treatment: Affected animals can be treated by a veterinarian according to the
symptoms shown, but if a lethal dose has been consumed treatment is of little
avail.
Good luck with getting the Elks Lodge to cooperate. I'm sure there are lots
of other plants that they could use that would look good and would not hurt
your horses. I would suggest taking as many DOCUMENTED sources of information
to the planning commision hearing as you can.
~Nora