Being out in nature is good for body, mind, and spirit, but when you come home from your nature walk with an itchy rash — or develop one soon afterward — that innocent outdoor stroll can seem more stress-inducing than relaxing.

Chances are, that rash was caused by brushing against a common plant, such as poison ivy. But there are many other plants that can cause contact dermatitis — skin inflammation cause by an irritant or a substance that produces an allergic reaction — or shorter-lived burning or itching.

Learn what these irritating plants look like and where you might encounter them so you can avoid them on your next outdoor adventure.

Poison ivy is found across the United States. You can come into contact with it while hiking in the woods, but it grows virtually everywhere — along roadsides, on fences, in backyards. Poison ivy leaves grow in clusters of three on vines that can grow up into trees or trail along the ground. Every part of the plant contains the compound called urushiol, which causes poison ivy’s notorious rash — the vine, the roots, the leaves, the flowers, and the berries.

A poison ivy rash typically appears a few days after exposure, and can even take a week or two if this is your first time in contact with the plant. When it does, you’ll know it: You’ll see very red skin, swelling, and blisters, and you’ll feel a serious itch. A strong corticosteroid skin cream or ointment can help with the inflammation. Your doctor may prescribe other medication if the inflammation is severe, to either suppress your immune system or to help further reduce the reaction. Anti-itch topical creams may also help.

2. Poison Oak: Not Related to Oak Trees

Poison oak is not related to oak trees, although its mature leaves somewhat resemble those of an English oak. Like poison ivy, poison oak is found throughout the United States, and it grows in forests as well as in dry spots, like sandy fields. Poison oak has deep green leaves that grow in clusters of three on a firm stem. Its yellow flowers are often described as hairy and its berries, fuzzy (unlike poison ivy’s smooth berries).

Also like poison ivy, every part of a poison oak plant contains urushiol in all seasons, meaning that any part of the plant can cause a rash if you come into contact.

Symptoms of and treatment for poison oak are the same as for poison ivy, and the severity of your reaction will depend on your individual sensitivity to the allergen.

3. Poison Sumac: Same Itch as Poison Ivy and Oak

Poison sumac is another plant found throughout the United States that contains urushiol, the allergen in poison ivy and poison oak. It grows as a shrub or small tree in wet environments, such as near stream banks and ponds and in wetlands.

You can recognize poison sumac by its red stems that branch off the main trunk and its compound leaves, each with 7 to 13 green, smooth-edged leaflets. Poison sumac flowers are greenish-yellow and its berries gray and flattened.

Every part of the poison sumac plant can cause a rash if you come in contact with it.

4. Wood Nettle: Beware the Stinging Hairs

Wood nettle is an herbaceous plant typically found in moist areas of woodlands. It tends to grow in large, dense patches, which can provide cover for wildlife. It is also a host plant for a number of insects and butterflies. It stands about 2 to 4 feet tall and has light- to medium-green stems covered with stiff, white hairs that sting if you rub against them.

The leaves of the wood nettle plant are medium- to dark green, roughly oval-shaped, and serrated. Young leaves are densely covered with stinging hairs, while older leaves tend to have fewer of them, often located on the underside of the leaf. In summer the wood nettle blooms, with lacy strands of white flowers.

The sting from wood nettle usually subsides within an hour. You may also be able to reduce the irritation by pouring water over the irritated area when you notice the stinging, then washing the area with soap and water.

Some people collect wood nettle for food and sauté or steam it like a green vegetable.

5. Stinging Nettle: Close Relative of Wood Nettle

Stinging nettle is the best-known member of the nettle family. It grows throughout the United States as well as in Europe, Asia, and North Africa. The plant tends to grow in dense patches near streams, along hiking trails, in ditches, and around farmland, often where the earth has been disturbed.

The stems of stinging nettle are singular, with few branches, and can grow 6 to 8 feet tall. The stems may be green or purple and may or may not have stinging hairs. The petioles (stem parts of the leaf) and undersides of the leaves also have stinging hairs.

The leaves of stinging nettle are longer than they are wide, and dark green, 2 to 4 inches long, with a tapered tip. Clusters of whitish flowers grow at the base of each pair of leaves along the stem.

Coming into contact with stinging nettle causes a sharp, painful sting, followed by a burning sensation and sometimes itching. The irritation can linger for several hours and cause hives near the site of contact which can last up to 24 hours.

Stinging nettle is sometimes gathered for food or to make into tea. It has long been a folk remedy for joint pain, eczema, arthritis, gout, and anemia. Cooking deactivates the stinging properties of stinging nettle.

6. Baby’s Breath: Irritating When Dried

If you’ve ever gotten roses from a florist, chances are they were clustered with sprays of tiny white or pink flowers known as baby’s breath. You might also see baby’s breath in cultivated perennial gardens.

Baby’s breath generally isn’t an irritant while it’s still alive, but when it’s dried, it can irritate the eyes, nose, and sinuses, as well as the skin. It can additionally cause asthma in people who touch it frequently, such as floral industry employees.

The skin irritation caused by baby’s breath is usually minor and temporary.

People who have become sensitized to baby’s breath and are having asthma reactions ideally should stop handling it.

Interestingly, double-flower varieties of baby’s breath tend to cause fewer reactions than single-flower varieties, so if you’re planting it in your garden or have a choice when ordering a bouquet, go for the double-flower option.

7. Leadwort: Look but Don’t Touch

Leadwort, also known as plumbago, is a mainly tropical shrub, but it can also be grown in the southern half of the United States. It is sometimes used by gardeners as a ground cover because of its tendency to spread underground and form a mat of plants.

Leadwort has shiny green leaves that turn red in autumn, and five-petal, medium-blue flowers that bloom in late spring or early summer and last until the first frost.

As lovely as this plant looks, resist any urge to touch it: Handling it can cause skin irritation, redness, or blistering. Wear gloves when working with it in the garden.

8. Ragweed: Sneezing and Skin Rash

Ragweed is best known for causing hay fever, or seasonal allergic rhinitis, in the fall. But it can also cause a rash in people who are allergic to ragweed pollen. The rash may appear as itchy red streaks on the skin or swollen eyelids.

A ragweed rash can develop after a person directly touches the plant pollen or is exposed to airborne pollen, making it difficult to avoid.

But if you have ragweed growing on or near your property, it may help your allergies to remove it.

Common ragweed has delicate, deeply lobed leaflets that are medium-green in color. The flowers — and sources of pollen — grow in “spikes” from the top of the plant and elongate over the summer.

Another type of ragweed, called giant ragweed, has similar flower spikes but very different leaves. The leaves at the bottom of the stalk have three or sometimes five lobes, while the leaves at the top of the plant are elliptical.

9. Giant Hogweed: Invasive Plant, Serious Rash

Giant hogweed is an invasive plant in Europe and North America and, according to the New York Department of Environmental Conservation, a “federally listed noxious weed” in the United States.

Contact with the sap of giant hogweed can cause serious skin and eye irritation, blistering, scarring, and even blindness if the sap gets in the eye. The skin rash may look like a second-degree burn and can leave you with long-lasting scars and sensitivity to sunlight.

Giant hogweed sap is phototoxic, which means it requires exposure to ultraviolet light to cause a reaction. If you touch giant hogweed — or think you might have — keep the exposed area away from sunlight for 48 hours, and wash it with soap and cold water as soon as possible. If you get sap in your eyes, rinse them with water and wear sunglasses. See a physician if you have a reaction.

You can recognize giant hogweed in part by its size: It can grow to 14 feet high or higher and has hollow, rigid stems 2 to 4 inches in diameter. Its deeply lobed, compound leaves can grow up to 5 feet across, and its white, umbrella-shaped flower heads, can be up to 2.5 feet across. The stems of giant hogweed are green with purple splotches and coarse, white hairs.