The beautiful flowers can easily be deceptive.
However one needs to be really careful with Alpin Roses. Especially for horses their flowers, leaves, berries and nectar have poisonous substances.
In general the Alpin Rose can be categorized into the Hairy and the Rusty-leaved Alpin Rose. Both species belong to the genus of Rhododendron and therefore to the heath family.
The toxic substance is called Acetylandromedol which has for horses even more poisonous effects than for humans. Unfortunately until today we do not know about the certain dose which causes death but in any case one needs to be careful.
In general one needs to control all places where horses are without supervision (e.g. pastures) if there are any poisonous plants.