Ornamental grasses are popular garden features, admired for their diverse textures, forms, and seasonal interest. While these plants enhance outdoor spaces, some varieties contain compounds that can pose a safety concern for people, pets, and livestock. Understanding the potential for toxicity is an important aspect of responsible gardening.
Toxicity in Ornamental Grasses
Toxicity in plants refers to their ability to produce natural compounds that can be harmful if ingested or, less commonly, through skin contact. While many widely cultivated ornamental grasses are generally considered safe, certain types produce specific chemical compounds that act as toxins, including alkaloids that interfere with normal bodily functions. The degree of harm depends on factors such as the specific plant species, the amount consumed, and the sensitivity of the individual or animal exposed. Different parts of a plant, like leaves or seeds, can also vary in their concentration of harmful substances.
Specific Poisonous Ornamental Grasses
Species within the Phalaris genus, such as reed canary grass (Phalaris arundinacea) and Harding grass (Phalaris aquatica), are notable for their chemical toxicity. They produce indole alkaloids that can cause significant health issues, especially in grazing animals like sheep, cattle, and horses. Toxicity is often higher in young, rapidly growing plants or under specific environmental conditions like frost or drought. Ingestion of Phalaris species can lead to two primary syndromes in livestock: “Phalaris staggers,” a neurological condition, and “sudden death syndrome” from cardiac disturbances. While primarily a concern for livestock, the presence of potent alkaloids means large-scale consumption by any mammal could lead to adverse effects.
In contrast, common ornamental fountain grasses, such as Pennisetum setaceum and Pennisetum alopecuroides, are generally considered non-toxic chemically for typical household pets. However, these grasses pose a different type of hazard due to their physical structure. Their bristly seed heads, known as awns, can become lodged in fur, eyes, ears, or nasal passages of animals, particularly dogs. These awns can cause irritation, infection, or even migrate internally, leading to more serious medical concerns.
Signs of Poisoning
In pets and humans, gastrointestinal upset is a common initial symptom, including vomiting, diarrhea, and abdominal discomfort. Animals may also exhibit lethargy or a loss of appetite. These signs can manifest within hours of ingestion.
More severe neurological symptoms, particularly from Phalaris species, can include muscle weakness, tremors, incoordination, difficulty standing or walking, excitability, head pressing, or even seizures. If a large quantity of toxic grass is consumed, cardiac symptoms such as difficulty breathing or an elevated heart rate may occur. If any of these symptoms are observed after a suspected plant ingestion, immediate action is necessary.
Safe Handling and Prevention
When working with ornamental grasses, wear gloves to protect skin from potential irritants or sharp edges. Always wash hands thoroughly with soap and water after handling any plants. Proper disposal of trimmings is also important; ensure they are placed in a secure compost bin or yard waste container where children and pets cannot access them.
Consider planting non-toxic alternatives in areas frequently accessed by children and pets to minimize risk. Supervising children and pets when they are outdoors, particularly near garden beds, can prevent accidental ingestion or contact with hazardous plants. Educating family members about which plants to avoid and the importance of not consuming unknown plant material is also an important preventative measure. If you suspect exposure to a poisonous plant, contact your local poison control center for guidance, or consult a veterinarian for pet concerns.