Heliotrope (Heliotropium europaeum
) is an upright, flowering, short-lived annual plant that is native to Europe, Western Asia and northern Africa. It is considered to be an invasive, noxious weed in many areas of the world where it has been introduced, such as western Australia and Tasmania. H. europaeum
has course haired stems and leaves. The leaves are oval or egg-shaped, greyish-green and positioned in alternate order. It produces white, tube-shaped flowers that are arranged in two rows along one side of the curved flower spike.
All parts of H. europaeum
contain pyrrolizidine alkaloids, which are known for causing liver damage to horses if ingested. Generally, the plant is unpalatable to horses, unless they lack sufficient forage to consume in their pasture. H. europaeum
is toxic also in dried form, and can sometimes get mixed up in haybales since it tends to grow in hayfields. Horses are more likely to ingest H. europaeum
if it contaminates their hay. Ingestion of the plant can cause pyrrolizidine alkaloid toxicity
in horses, which can eventually results in liver failure.