Lemongrass is a perennial plant native to tropical and subtropical regions, where it grows in dense, robust clumps. It is instantly recognizable by its distinct, potent lemon-like aroma, which is particularly strong when the stalks or leaves are bruised. This fragrance has made lemongrass a staple in Southeast Asian cuisine, where the fibrous stalks impart a bright, citrusy flavor to dishes like curries and soups. Beyond culinary applications, the plant is often consumed as a soothing herbal tea in traditional medicine.
Native Herbivores and Wild Consumers
In native environments, such as the African savanna, lemongrass is a component of the grazing diet for several large herbivores. Growing in tall, dense clumps, it provides a readily available source of forage. Specific wild consumers include elephants, zebras, and various species of antelope.
These large mammals incorporate lemongrass into their grazing routines because it is a plentiful and nutritious food source. While the plant is tough and fibrous, the digestive systems of these wild ruminants are adapted to process such coarse vegetation as part of a mixed diet.
Pests That Damage Lemongrass
For gardeners and commercial growers, the primary consumers of lemongrass are pests that cause significant damage. Insect pests are among the most common culprits, targeting the leaves and stems.
Sap-sucking insects like aphids and spider mites feed on the plant’s juices, leading to yellowed leaves and stunted growth. Other insects, such as caterpillars and armyworms, chew through the foliage, leaving visible holes. Small burrowing mammals, including gophers and voles, target the plant’s base. They consume the roots and rhizomes, which destabilizes and can destroy entire lemongrass clumps.
Safety for Common Domestic Animals
Determining if lemongrass is safe for domestic animals requires distinguishing between the whole plant and its concentrated oil. The plant contains cyanogenic glycosides, which can convert to hydrogen cyanide in the digestive system of some animals. For dogs and cats, consuming the fibrous leaves can result in gastrointestinal upset, vomiting, and diarrhea, and large quantities risk internal blockage.
In contrast, the commercial livestock industry uses controlled amounts of the essential oil as a sensory feed additive. When mixed into complete feed formulations, lemongrass oil is considered safe for species including horses, cows, goats, and poultry. However, the undiluted essential oil is highly concentrated and poses a significant toxicity risk, especially to small pets like cats, and must be kept out of reach.
Why Some Animals Avoid Lemongrass
Lemongrass actively deters many animals, particularly insects and small mammals, due to its inherent chemical characteristics. The potent aroma and flavor are primarily due to a high concentration of monoterpenoids, notably citral. These compounds are structurally related to citronella, which is known for its repellent qualities.
The strong, oily nature of these volatile compounds acts as a natural defense mechanism. The odor confuses or overwhelms the olfactory systems of many insects, deterring mosquitoes, ticks, and stable flies. For larger grazers, the tough, woody texture and fibrous nature of the stalks make it less palatable than softer grasses, causing them to bypass it for easier forage.