The question of whether poison ivy exists in arid states like New Mexico is common, given the state’s reputation for high desert landscapes. The plant responsible for the notorious rash is Toxicodendron. While the eastern variety (T. radicans) is a vine, the type found in New Mexico is typically Western Poison Ivy (T. rydbergii). This plant is present across the state, and knowing its specific habitats and features is the best defense against accidental contact.
Where Poison Ivy Grows in New Mexico
The notion that New Mexico’s dry climate prevents the growth of poison ivy is inaccurate; it is widely distributed across the state, primarily in areas that retain moisture. The plant thrives in mountainous regions and along water sources, often at elevations ranging from 5,300 to over 9,100 feet. This range includes the Ponderosa pine and pinyon-juniper-oak forests found in the state’s mid-to-high elevations.
The most common locations for encountering Western Poison Ivy are along riparian corridors, such as the banks and floodplains of rivers, creeks, and canyons. These moist habitats provide the necessary conditions for the plant to form dense, single-stemmed, or branching colonies. While less common in the open, arid high desert plains, it can still be found in disturbed areas, fields, and along roadsides where water runoff collects.
Key Features for Identification
Western Poison Ivy in New Mexico grows as a low, upright shrub, typically one to three feet tall, rather than a climbing vine. The most recognizable characteristic is the arrangement of its leaves in clusters of three leaflets, leading to the familiar warning, “leaves of three, let it be.” These alternate leaves have leaflet blades that are oval-shaped with pointed tips and often feature irregularly notched or toothed edges.
The visual appearance of the plant changes throughout the year, which can complicate identification. New growth in the spring and the foliage in the fall often display a reddish or yellowish-orange hue. During the summer, the leaves are green and may appear shiny. In the late summer and fall, the plant produces small, round, grayish-white berries that persist through the winter, meaning the plant remains a threat even when leafless.
Responding to Exposure and Rash
The blistering rash is an allergic reaction caused by Urushiol, a clear oil found in all parts of the plant, including the roots, stems, and leaves. This oil is potent; a trace amount—less than a grain of salt—is enough to cause a reaction in most people. Urushiol adheres quickly to the skin, clothing, pets, and tools, remaining active on surfaces for years.
Immediate action is necessary to minimize the reaction after suspected contact. The most effective step is to wash the exposed skin thoroughly with soap, such as dishwashing soap, and cool water as soon as possible. Washing immediately can remove up to 100% of the oil, but effectiveness drops significantly after the first few minutes, as the oil bonds to the skin. Contaminated clothing and tools should be washed with hot water and detergent or wiped down with rubbing alcohol.
If a rash develops, which typically appears within 12 to 48 hours, over-the-counter treatments can help manage symptoms. Applying calamine lotion, hydrocortisone cream, or taking an oatmeal bath can help relieve the intense itching. Medical attention is necessary if the rash is severe, covers a large portion of the body, is located on the face or genitals, or if signs of infection or difficulty breathing occur.