Frequently (and not so frequently) Asked Questions
BRIEF: Are Leyland Cypress trees toxic to horses?
QUESTION:
We just purchased some Leyland Cypress ((Cupressocyparis leylandii) trees
to use as a break because they grow fast. We want to find out if they are
toxic to horses and other animals. We have a farm west of Seattle,
Washington and have a large variety of animals (ducks, peacocks, geese,
emus, chickens, horses, donkey, goats, etc).
ANSWER:
The cypresses probably have some thujone among their monoterpenes, so you
probably wouldn't want to make it a major forage source. On the other hand, if
these are baby trees, the animals are more of a threat to them than vice versa.
Of course, when prepared from a different plant, a thujone-rich abstract became
famous as absinthe... And this essential oil was once used as a worm medicine.
That's why absinthe is sometimes called wormwood.