Lantana is a genus of flowering shrubs, with Lantana camara being the most common species used in landscaping for its vibrant, clustered blooms. While Lantana does not possess true thorns, many common varieties are armed with sharp structures. These pointed growths are botanically classified as prickles, which are distinct from the thorns found on plants like roses or hawthorns.
The Physical Reality of Prickles
The distinction between a thorn and a prickle is based on botanical origin. True thorns are modified stems containing vascular tissue, connecting them to the plant’s internal transport system. In contrast, Lantana’s prickles are outgrowths of the plant’s epidermis, or outer layer. Because prickles lack an internal vascular connection, they can often be removed more easily than a thorn.
These sharp structures are typically located along the square-shaped stems of the shrub, particularly on weedy or wild varieties of Lantana camara. Their primary function is to serve as a physical deterrent, protecting the plant from being eaten by grazing animals and other herbivores. While some newer cultivated hybrids have been bred to be less prickly, the presence of these sharp defenses is a characteristic trait of the genus.
Safe Handling Practices for Skin Contact
Anyone working closely with Lantana should take precautions to avoid physical injury and skin irritation. The best defense against the prickles and the plant’s rough foliage is to wear protective clothing. This includes using thick gardening gloves, wearing long sleeves, and covering the legs when pruning, weeding, or handling the shrub.
The leaves and stems of Lantana can also trigger contact dermatitis in sensitive individuals. This reaction is a form of skin irritation or rash that is chemical, not physical, in nature. If a scratch or rash occurs, the area should be cleaned immediately with soap and water to remove any plant sap or irritating hairs. Persistent itching or a severe rash may require consulting a pharmacist or dermatologist for appropriate topical treatment.
Toxicity Risks Beyond Physical Contact
While the prickles pose a mechanical hazard, the plant presents a more serious chemical safety concern if parts are consumed. All parts of the Lantana plant are considered toxic, but the unripe, green berries and the leaves contain the highest concentration of harmful compounds. The primary toxins are triterpenoid compounds, specifically lantadene A and lantadene B, which target the liver.
Ingestion by humans or pets can cause a range of symptoms, beginning with gastrointestinal upset like vomiting, diarrhea, and abdominal pain. In severe cases, especially in livestock and small animals, the toxins can lead to liver failure. Liver failure may manifest as jaundice, or a yellowing of the skin and eyes. This toxicity requires immediate medical or veterinary attention if suspected.