Battling Invasive African Rue

The basilis -- known as the ‘king of the serpents’ -- was the most fearsome creature in all mythology, capable of cracking stones with just its breath. According to lore, the only substance on Earth that could poison the mighty basilisk was rue, a fragrant perennial herb. And like the fictional basilisk of yesteryear, Texas livestock and animals of today are at risk from a dangerous form of rue, which can be lethal if consumed.

Native to the deserts of North Africa, African rue (Peganum harmala) first appeared on North American soil in New Mexico around 75 years ago and today has spread into Texas and Arizona. African rue is bright green in color and grows in bushy clusters that can be a foot tall when mature. It sprouts narrowly segmented leaves and white flowers with five petals that bloom from April into the early fall. The fruit and seeds of African rue contain four highly poisonous alkaloids that are toxic to cattle, sheep, horses and some wildlife. Although animals generally avoid eating rue, they will consume it if faced with starvation or severe mineral deficiencies.

Because it is extremely drought resistant, African rue is able to out-compete native grasses for limited water and nutritional resources. It spreads rapidly through both its seeds and roots, and is often accidentally dispersed by farm equipment, highway mowers and any other vehicles that may come into contact with it.

The Nature Conservancy of Texas is addressing the spread of African rue at three of its properties -- Sandia Springs, Diamond Y Spring and Independence Creek preserves -- and is preparing to battle the encroaching exotic in the Davis Mountains conservation area in Far West Texas.

Although chemicals can be used to treat African rue, identifying the plant and taking precautions to prevent its spread are Texans best hope for control and eradication.

To find out more about our conservation work, including invasive species control, visit nature.org/texas.