For instigating itches, blisters, rashes, and general discomfort, few plants in Texas can compete with poison ivy. Although a fortunate few people are immune to poison ivy’s deleterious effects, a majority of the population experiences adverse physical reactions after coming in contact with it. The unpleasant results of a “brush” with poison ivy may last for days, weeks, or even months.

Last week, we recommended kickstarting your healthy resolutions by taking a hike in one of the many amazing state parks in Texas, and now it’s time to take a look at one of the big concerns with many hikers, new and experienced.

Poison ivy has been irritating people for a very long time. In 1609, Captain John Smith gave the plant its apt name. He thought it resembled English ivy in appearance, but went on to observe that “the plant causes abominable itchynge.” Poison ivy is a member of the Cashew family, and it grows throughout Texas and in many types of terrain, including swamps, forests and fields. Poison ivy can grow in full sunlight, as well as in nearly full shade, and preferred habitats include recently disturbed fields, but you may also find it in your flower garden or lawn.

Poison ivy grows in various ways. As a ground cover, it spreads outward and creates a knee-high thicket of foliage. As a free-standing shrub, it can grow as tall as 10 feet, with one stem and a few side branches. As a vine, poison ivy uses brown aerial roots to attach itself to the sides of trees or other objects. In this form, poison ivy reaches its greatest size.

“Leaves of three, let them be.” Poison ivy has compound leaves; that is, each leaf is made up of distinct parts called leaflets. The shape, color, and texture of poison ivy leaflets vary. Poison ivy’s trademark leaf triads are reddish when they first appear in the spring, but turn green during the summer. Another wild vine—Virginia creeper—is sometimes mistaken for poison ivy. However, Virginia creeper more often has five leaves to a branch rather than three. Virginia creeper is not only harmless, but makes for a beautiful fall foliage plant. The second half of that last statement is also true of poison ivy.

The green of the plant’s leaves in summer yields to brilliant reds, yellows and oranges in the fall. Their autumn brilliance is due to pigments characteristic of the Cashew family. Poison ivy fruits are clusters of tiny, pumpkinlike seeds with an off-white or pale yellow rind. The fruits contain the chemical irritant urushiol, but that does not stop birds from eating them. Urushiol is far more problematic for humans. Urushiol is a colorless oil that oozes from any cut or crushed part of the plant, including both stem and leaves. Simply brushing against a plant may not cause a reaction. On the other hand, a person may develop dermatitis without ever coming into direct contact with poison ivy. Sticky and virtually invisible, urushiol can be carried on the fur of animals, garden tools, golf balls, or on any object that has come into contact with a broken plant. After exposure to air, urushiol turns brownish-black, making it easier to spot.

The severity of reaction varies from person to person and may also change from year to year for some people. Severe reactions include swelling in the throat, dizziness, a burning sensation, weakness, and breathing problems. If you experience extreme itching or if infection sets in, seek medical attention. And remember: you can have an allergic reaction to poison ivy even if you never leave your house. Anything or anybody that has come into contact with poison ivy can spread it.

The best preventative for poison ivy is to avoid it. Don’t touch the plant or walk through it. Never grab leaves along a trail or fence. If you must walk through poison ivy, step on the plants with the sole of your shoe and always wear long pants.

The plant’s almost invisible oily resin sticks to most surfaces, and can even be carried in the wind or in smoke when it is burned. Standard barrier creams offer little protection against poison ivy, so if you have had a brush with the plant, wash all exposed areas of your body with cold, running water as soon as you can reach a stream, lake or garden hose. If you do this within five minutes of exposure, the water should deactivate the urushiol in the plant’s sap and keep it from spreading to other parts of the body.

After returning home, wash down all clothing outside with a garden hose before bringing it into the house, where resin can easily be transferred to rugs or furniture. Since urushiol can remain active for months, it is important to wash all camping, hiking, and hunting gear that may be carrying the resin. If you come down with a rash, avoid scratching the blisters. Cool showers will help ease the itching, and over-the-counter preparations, such as calamine lotion, may help relieve mild rashes. Soaking in a tepid bath with an oatmeal or baking soda solution is recommended to dry oozing blisters.

Poison ivy doesn’t have to get under our skin. With a little practice and some preventative measures, we can easily identify and avoid the plant. Knowing its benefits, we can learn to coexist with poison ivy when fishing, hunting or engaging in other outdoor pursuits and even respect it as another fascinating aspect of our state’s natural beauty.