Iguanas, particularly the invasive green iguana, cause considerable damage to residential landscapes by consuming foliage, flowers, and tender new growth. These large, herbivorous reptiles can quickly defoliate ornamental shrubs and flowering plants. Creating an iguana-resistant garden does not require installing physical barriers or using harsh chemical deterrents. Strategic planting of species that these reptiles naturally dislike offers an effective and aesthetically pleasing solution. Understanding the specific features that make certain plants unappealing allows you to modify your landscape.
Specific Plants Iguanas Will Not Eat
Iguanas avoid plants with strong odors, toxic compounds, or a physical texture that is difficult to chew. Strategically planting these repellent species can protect more vulnerable, palatable plants in the landscape. Grouping these plants by their primary deterrent characteristic helps in selecting the right species for different areas of the yard.
Toxic or bitter-tasting ornamentals are effective deterrents, as iguanas learn to avoid them after sampling the foliage. Oleander (Nerium oleander) is effective because it contains cardiac glycosides, which are toxic to many animals. The sap of Crown of Thorns (Euphorbia milii) and Milkweed (Asclepias spp.) also contains toxic and irritating compounds. These selections provide vibrant color while discouraging feeding.
Another category includes plants with powerful scents or unpalatable flavors that overwhelm the iguana’s senses. Citrus trees (Citrus spp.) are avoided due to their strong aroma and thick, difficult-to-chew leaves. Society Garlic (Tulbaghia violacea) releases a pungent, garlic-like odor when bruised, making it suitable for low border planting. Herbs like rosemary, oregano, and thyme are also generally avoided due to their strong chemical compounds.
A third group consists of plants with tough, fibrous, or spiny textures that are physically challenging to consume. Agave and other large succulents are ignored due to their thick, rigid leaves and sharp edges. Plants with leathery foliage, such as Cordyline and Coontie (Zamia integrifolia), are unappealing because the leaves are too tough to chew easily. The fine, hairy texture of Silver Buttonwood (Conocarpus erectus var. sericeus) and the fuzzy texture of Chenille plants are physical deterrents.
What Makes Certain Plants Unpalatable
Iguanas avoid specific plant species due to sensory and post-ingestive mechanisms. Plants have evolved defenses against general herbivory by producing specialized chemical compounds called secondary metabolites. These metabolites, which include alkaloids, terpenes, and phenols, function solely as defense agents rather than aiding in the plant’s growth.
Many plants contain chemical compounds that taste bitter or cause irritation upon consumption. Toxic saps or cardiac glycosides cause illness, and iguanas quickly learn to associate this negative experience with the plant’s appearance or scent, leading to conditioned food aversion. Compounds like capsaicin, found in chili peppers, create a burning sensation that deters feeding.
Physical defenses also play a significant role in creating an unpalatable meal. Some plants concentrate calcium oxalate crystals, known as raphides, within their tissues. When chewed, these microscopic crystals are released, causing mechanical irritation and a painful sensation in the mouth and throat. Furthermore, the leaves of certain species possess a high fiber content, making them difficult to tear and digest, or they feature a tough, leathery texture.
Designing Your Landscape for Iguana Deterrence
Effective iguana deterrence relies on selecting the correct plants and their strategic placement within the landscape. The goal is to create a multi-layered defense system that protects susceptible plants and makes the property less attractive. This involves using repellent species as living barriers and perimeter plantings.
A successful strategy is using avoided plants to create dense borders around the yard’s edges or around garden beds containing appealing plants, such as hibiscus or orchids. This perimeter planting should be dense enough to act as a physical barrier, forcing iguanas to encounter the unpalatable foliage first. For trees or shrubs iguanas climb, planting low-growing, strong-scented deterrents around the base can discourage them from approaching the trunk.
Consider the height and density of the deterrent plants, ensuring they form a continuous, uninviting barrier. Using container gardens filled with vulnerable plants is effective if the containers are placed on raised, smooth surfaces and surrounded by strongly scented potted herbs. Maintaining the health and density of the repellent plants is necessary to ensure their deterrent properties, whether scent or texture, remain strong year-round.