Naturally found in many of the world’s tropical regions, iguanas are some of the most visually striking reptiles. Covered in colorful scales, equipped with spine-like appendages, and set apart by a dewlap below their chins, they can be described as modern-day dinosaurs. Interestingly, though they tend to have sharp teeth, these lizards are primarily herbivorous. They can subsist on the nutrients found in a wide variety of leafy greens, fruits, and vegetables.
Though iguanas were once solely distributed throughout countries like Brazil, Mexico, and Paraguay, they are now found in the warmer states of the US, Southeast Asia, and Polynesia. In some of these places, their introduced communities have become invasive. They are associated with reduced numbers of many endemic plants. Their colonies can also spread dangerous pathogens, such as salmonella.
Iguanas can be a nuisance in private landscapes and public parks. These exotic animals, when found in uncontrolled numbers, can quickly become garden pests. They leave potentially contaminated droppings in the areas where they bask. Unsightly, these tend to emit an unpleasant smell. Moreover, juvenile iguanas are known for feeding on important birds and pollinators. To keep them out of your property, avoid growing squashes, roses, and greens. Instead, opt for the iguana-resistant plants below.
1) Oleander (Nerium oleander)
The sole member of its genus, Nerium, the oleander tree is a lovely subtropical species with ornamental properties. It typically grows as a shrub in the wild, with erect stems that can measure as much as 20 feet (6 meters) long in optimal conditions. In maintained landscapes, its shoot can be trained to grow as a singular trunk with branches that gracefully splay out and produce showy blooms.
In the garden, oleander can bring a wealth of environmental benefits. Depending on the quality of its root and shoot structures, these may far exceed its ornamental properties in overall value. While it attracts beneficial insects, such as pollinators, it repels many herbivores due to its toxic properties. This vigorous grower contains cardiac glycosides like oleandrin and oleandrigenin.
When ingested by herbivores, a substantial amount of oleander tissues can adversely affect the nervous system and gastrointestinal tract. Iguanas are wise to keep away from this toxic species as even its sap can cause allergic reactions upon contact. Clippings of the plant can be placed around areas that these reptiles frequent, such as branches or rocks above which they bask. To avoid skin and eye irritations, make sure to use protective clothing and gloves while handling this plant.
2) Lilyturf (Liriope muscari)
Also known as monkey grass or border grass, lilyturf is often used as a groundcover plant in temperate regions. It is remarkably easy to grow and can spread in almost no time to create lush mass plantings along the borders of driveways, hiking trails, and footpaths. Oftentimes, this self-propagating herb is grown as a form of erosion control on sunny to partly shaded slopes.
Lilyturf is often avoided by iguanas, though its true mechanism for pest repellence continues to be a point of debate. Its grass-like leaves contain compounds with insect-repellent properties. These are likely undesirable as a source of nutrients for herbivores and plant-eating insects. As a result, you can plant this species in rows along areas that may be frequented by troublesome visitors. Just make sure to keep in mind that its roots can spread on their own and produce invasive colonies.
Hardy to USDA zones 6 – 10, lilyturf is able to tolerate a variety of ambient conditions. Its well-established stands remain evergreen all through the year. They can survive through periods of frost, intense heat, and drought as long as they are provided with fertile substrates and supplementary moisture. Unfortunately, in areas outside of its native range, lilyturf is not known for being beneficial to wildlife. If you intend to grow it in your garden, minimize its spread by restricting its roots to within containers.
3) Society garlic (Tulbaghia violacea)
A recipient of the RHS Award of Garden Merit, society garlic and its charming varieties can play many roles in an herb garden. While its flavorful leaves can act as a culinary substitute for chives and other types of garlic, they are great for repelling a wide range of pests. The lengthy leaves emit a distinct fragrance when they are mechanically damaged or rubbed. The scent tends to ward off insects and larger herbivores.
Low-maintenance, this flowering plant is frequently cultivated as an ornamental. Its edible, grass-like leaves add lovely texture and color to gardens of all sizes. They can be used as a backdrop for container gardens, where they are likely to protect smaller plants from hungry iguanas and grazers. As a bonus, this plant produces eye-catching, lavender blooms in summer to fall. Star-shaped, the flowers are borne on clusters atop floral stems that rise above the foliage.
If you intend to use society garlic in sites that are frequented by herbivorous reptiles, you’ll need to cultivate a mass planting. Just two or three stands may not be effective, particularly in the presence of high-value fruits and vegetables. Consider growing strategically placed rows of this species to increase the range over which its scent may spread.
4) West Indian jasmine (Ixora spp.)
Iguanas generally ignore the tough shoots of West Indian jasmine shrubs. Known for producing leathery, dark green foliage, these evergreen plants are some of the hardiest species throughout their native range. Herbivores are unlikely to feed on their tough leaves, making them favorable as hedge accents in pest-repellent gardens. Moreover, their dense clusters of star-shaped flowers attract dozens of beneficial insects.
Also known as jungle geranium, siantan, or rangan, there are hundreds of species of West Indian jasmine. Some types grow as common shrubs in the southeastern states of the US, where the invasive green iguana tends to wreak havoc in many backyard gardens. Cultivating Ixora shrubs around the perimeter of a backyard should help keep out these undesirable reptiles.
Able to grow to various sizes, with the potential to rival the heights of small trees, West Indian jasmine can be arranged in rows to create a natural barrier. Instead of spotting your garden’s nutritious produce and tender blooms, herbivores should be dissuaded by an initial foray into this shrub. Its branches and leaves can be dense enough to block out medium-sized animals.
5) Milkweed (Asclepias spp.)
The shrubs of the Asclepias genus are commonly called milkweeds because of the milky appearance of their sap or latex. This whitish substance is released wherever its cells have been damaged, quickly sealing the opening and serving as a barrier that repels pests and herbivores. The toxic sap contains cardiac glycosides, many of which can adversely affect humans and grazers upon contact or ingestion.
The chemical defenses of the plant primarily function as a means to protect its foliage from voracious caterpillars and their parasites. By extension, these likewise discourage herbivorous reptiles and mammals from overgrazing the leaves. The latex of some species is potent enough to severely disrupt normal cell functioning in animals and humans. In fact, some tribes once used it to coat their arrows while hunting.
When found in adequately dense rows, milkweed shrubs should serve as an iguana-resistant barrier. Their sap-filled stems and leaves are unappetizing to herbivorous reptiles and should force them to search for food elsewhere. Apart from growing these shrubs to protect your garden, you can also cultivate them to attract monarch butterflies and other beneficial insects.
6) Chili peppers (Capsicum spp.)
Nothing spells pest resistance like plants of the Capsicum genus. These flowering and fruit-producing members of the nightshade (Solanaceae) family are some of the best natural defenses against troublesome grazers. A taste of capsaicin-rich peppers should send them scurrying away from your property and force them to search for other grazer-friendly fruits elsewhere.
Most mammals and reptiles are likely to find the burning sensation of chili peppers unpleasant. This can linger in their mouths and cause temporary discomfort in the digestive system. Though the feeling does go away after some time, animals that have had a taste of these fruits are likely to avoid them in the future. You can expect iguanas to instinctively turn away from Capsicum species, especially during their fruiting period.
In the absence of actual chili pepper plants, you can make use of their store-bought fruits or powders to create an iguana-repellent spray. You may mix the pulpy material and seeds with other pesticidal plants or oils, such as those from garlic bulbs and strongly-scented herbs. Spray the water-based solution onto plants that may require additional protection from reptiles.
7) Citrus trees (Citrus spp.)
Citrus trees are some of the most wondrous and beneficial fruiting plants throughout their native range. Known for producing strongly-scented, vitamin C-rich fruits, these trees are now grown in dedicated orchards and farms all across the globe. Their essential oils are often in demand as they are added to perfumes, juices, medicines, and even organic repellents. While they appeal to us humans, they are the bane of many insects and grazers.
Lemons, oranges, and limes are just some of the fruits produced by the dozens of species and cultivars of citrus trees. The scent of these fruits is strong enough to dissuade iguanas from basking close to citrus trees or traveling across their branches. When the scent is distributed throughout the garden or landscape, more grazers are likely to keep away from the general area. Herbivorous reptiles consider the fruits unpalatable. Outside of the fruiting period, they may also find the leaves unappetizing.
As suggested with the pulp of chili peppers, the oils and juices of citrus fruits can be incorporated into an organic, homemade iguana-repellent spray. Just a few drops of these fruits’ scented juices should suffice to diffuse their scent throughout the garden. Any visiting iguanas are likely to retreat and escape to other areas that are devoid of citrus fruits.
8) Fire croton (Codiaeum variegatum)
Set apart by its eye-catching flurries of vibrant foliage, fire croton is a wonderful addition to tropical gardens. This evergreen shrub is fantastic as a potted specimen or as a component of natural fences or perennial hedges. Its shoots can measure as much as 9 feet (2.7 meters) tall in optimal conditions, providing ample coverage and shade for other low-growing plants. Due to its ornamental features, it is now available in dozens of striking cultivars.
Though fire croton can visually draw in its spectators, many animals are wise enough to keep away from its bright leaves. Just as many dangerous plants and animals signify the presence of their toxins or venom by sporting vivid colors, this species seems to flaunt its poisonous profile. Its sap, which is exuded through the mechanically damaged cells of its leaves, contains potentially carcinogenic oils and allergenic compounds.
The leaves of the fire croton are definitely the last things a hungry iguana would consider feasting on. When they are abundant enough to form a natural barrier, these reptiles will think twice before entering your property. Note that even children and pets may be affected by this plant’s sap and its seeds, which likewise contain toxic compounds.
9) Silver buttonwood (Conocarpus erectus var. sericeus)
Iguanas generally dislike silver buttonwood, which occurs as a multi-trunked tree that can grow as tall as 15 – 20 feet (4.6 – 6 meters). This specific variety of buttonwood tree is often grown as an ornamental plant. Its silvery foliage gives its canopy a muted appearance, one which may seem to incite an air of relaxation in gardens and parks.
Low-branching, the silver buttonwood produces leaves that are covered in distinctly silky hairs. Each spring, its greenish-to-whitish blooms appear in cone-like inflorescences. These emit a scent that is quite similar to that of artificial grape powder. It’s likely that iguanas avoid these plants for several reasons. First, its hairy leaves are unpleasant to them in terms of taste and texture. Second, the fragrant inflorescences may throw them off.
If you find that your garden is often plagued by herbivorous reptiles, try growing a few stands of these trees along the perimeter. Once they mature, they should provide both structure and protection to your property. The full form of this tree may cast lower-growing plants in the shade, so keep in mind that it may need to be pruned back each year.
