Poisonous Plants of the Appalachian Trail

Unless you plan on feasting upon nature's bounty, there are really only eight plants which you need to beware of while hiking or camping in the Appalachian Mountains. These eight plants are known to cause poisoning, or rather dermatitis, upon contact. A few of these plants are only found in low areas, along roads or streams, or in specific regions, so it is unlikely that you will encounter all of them unless you are traveling over a long stretch of the Trail. Although a few of these plants are edible or medicinal when harvested and prepared correctly, they are best avoided by the uninitiated.

These eight plants are listed below along with a suggested method for memorizing the Itchy Eight of the Appalachians:

Common name: Poison Oak

Scientific names: Toxicodendron pubescens, Rhus toxicodendron

Toxic parts: All parts

Duration: Perennial

Habitat: Thickets, new growth forests, dry and sandy fields

Height: 2-4 ft.

Bloom color: Yellow

Bloom time: March-April

Leaves: Alternate, trifoliate, lobed, hairy (resembling White Oak), about 6 inches in length

Fruit: Greenish white, round, ¼ in. diameter

Description: Atlantic Poison Oak is an erect shrub between 1 ft. to 3 ft. in height. The leaves are approximately 6 in. long, alternate, with three leaflets often resembling the leaf of the white oak. The leaflets are normally hairy and variable in size and shape, turning yellow or orangish-red in autumn. The fruit is tannish-white or greenish-white, small drupes, covered with a velvety pubescence (fuzz).

Look-alikes: Staghorn Sumac (Rhus Typhina ), Eastern Poison Ivy (Toxicodendron radicans ) and Western Poison Ivy (Toxicodendron rydbergii ).

Special Notes: You are not that likely to encounter this plant unless you venture into low land areas in the southeast, but you may, on occasion, encounter Poison Oak.

Common name: Poison Ivy

Scientific names: Toxicodendron radicans, Rhus radicans

Toxic parts: All parts

Duration: Perennial

Habitat: Wooded edges, rocky areas, open fields, many soil types

Height: 6-18 in. (groundcover), up to 4 ft. (shrub)

Bloom color: White, green or brown

Bloom time: April-June

Leaves: Alternate, trifoliate, ovate, dentate

Fruit: Amber, ¼ in. diameter

Description: Poison Ivy is not a true Ivy (Hedera). It can either be a woody vine, a groundcover, or a shrub. The height of Poison Ivy is variable. The leaves are trifoliate with three almond-shaped leaflets containing few or no teeth. The leaflets are alternate and approximately 1-4 inches long with either a light or dark green color. Leaflets are smooth on top, sometimes shiny, turning reddish in the autumn. The fruit, which is small drupes, is amber or grayish-white in color.

Look-alikes: Virgin's Bower (Clematis virginiana ), Box-elder (Acer negundo), Virginia Creeper (Parthenocissus quinquefolia ), Poison Sumac (Toxicodendron vernix ), Atlantic Poison Oak (Toxicodendron pubescens ), Western Poison Ivy (Toxicodendron rydbergii ), blackberries and raspberries (Rubus spp. ) and Fragrant Sumac (Rhus aromatica ).

Special notes: This plant is used by some homeopaths to create the remedy Rhus tox. Eastern Poison Ivy is found throughout the Appalachian Mountains.

Common name: Nettles

Scientific name: Urtica spp.

Toxic parts: Stinging hairs on stems and leaves

Duration: Mostly perennial, some annual

Habitat: Thickets, roadsides, waste grounds, fields, fertile soil

Height: 2-4 ft.

Bloom color: Green

Bloom time: June-September

Leaves: Opposite pairs, elliptic, lanceolate, ovate or circular, serrate, hairy

Description: There are 30-45 species of nettles in the genus Urtica . Most are perennial, but some are annual, and most contain stinging hairs on both the leaves and the stems. They are generally 2-4 ft. in height, but can grow larger. The leaves and stalks are opposite pairs, with leaf blades that are either elliptic, lanceolate, ovate or circular, and usually serrated or toothed.

Look-alikes: Lamium spp.

Special notes: Nettles are used in the preparation of medicines, as teas, and also steamed and eaten as a cooked green.

Common name: Poison Sumac

Scientific names: Toxicodendron vernix, Rhus vernix

Toxic parts: All parts

Duration: Perennial

Habitat: Wet soil, swamps, bogs, flood plains, wet slopes, stream-banks

Height: up to 15 ft.

Bloom color: Yellow, green or brown

Bloom time: June-July

Leaves: Alternate, pinnate, ovate, entire

Fruit: White drupes, ¼-⅓ in. diameter

Description: Poison Sumac is a small tree or large woody shrub that grows up to 15 ft. in height. It has alternate pinnate leaves with 7-13 entire, or toothless leaflets. It can be distinguished by its red rachis (stem which connects the leaflets) and its smooth shiny leaves. The leaflets are 2-4 inches long and green to greenish yellow, changing to yellow, red, or deep purple in the autumn. The fruit begins as greenish drupes then changing to white when ripe.

Look-alikes: Other sumacs

Special notes: You will only come across Poison Sumac in very wet soils or flood plains.

Common names: Trumpet Creeper, Trumpet Vine, Cow-itch Vine

Scientific name: Campsis radicans

Toxic parts: Sap, leaves and flowers

Duration: Perennial

Habitat: In trees, moist woods, fence-rows

Height: up to 35 ft. (vine)

Bloom color: Red or orangish yellow

Bloom time: June-September

Leaves: Opposite, pinnate, elliptic, lanceolate, obovate or ovate, dentate

Fruit: Brown, 3-5 in. long

Description: Trumpet Creeper is a large woody vine and perennial best known for its large trumpet-like flowers. The leaves are opposite, pinnate, ovate and dark green with 4-6 pairs of leaflets. The leaves are 2-4 inches long. From June-September its large trumpet-like flowers bloom in beautiful orange to red colors. The fruit is a brown pod usually about 3-5 inches in length.

Look-alikes: Sometimes inexperienced individuals mistake the Trumpet Creeper for Eastern Poison Ivy (Toxicodendron radicans ).

Special Notes: Hummingbirds love the Trumpet Creeper. It will most likely be encountered along fence-rows, and occasionally growing on telephone poles.

Common names: Poison ivy

Scientific name: Toxicodendron rydbergii

Toxic parts: All parts

Duration: Perennial

Habitat: Woods, thickets, moist soils

Height: 2-7 ft.

Bloom color: White or yellow

Bloom time: May-July

Leaves: Alternate, trifoliate, ovate, variously lobed

Fruit: Yellowish, small, round, ¼ in. diameter

Description: Western Poison Ivy is an upright woody shrub growing between 2-7 feet in height. The alternate, bright-green leaves are trifoliate with three ovate to rhombic leaflets, 1-6 inches long. The leaflets are round, dentate or entire. Leaflets are smooth on top, sometimes shiny, turning reddish in the autumn. The fruit, which is small drupes, is round and yellowish in color.

Look-alikes: Virgin's Bower (Clematis virginiana ), Box-elder (Acer negrundo ), Virginia Creeper (Parthenocissus quinquefolia ), Poison Sumac (Toxicodendron vernix ), Atlantic Poison Oak (Toxicodendron pubescens ), Eastern Poison Ivy (Toxicodendron radicans ), Blackberries and raspberries (Rubus spp. ) and Fragrant Sumac (Rhus aromatica ).

Special Notes: This plant is used by some homeopaths to create the remedy Rhus tox. Like Eastern Poison Ivy, Western Poison Ivy is found throughout the Appalachian Mountains.

Common name: Wild Parsnip

Scientific name: Pastinaca sativa

Toxic Parts: Shoots and leaves (phytophototoxic)

Duration: Biennial

Habitat: Roadsides, waste places

Height: 2-5 ft.

Bloom color: Golden or yellow

Bloom time: May-July, October

Leaves: Alternate, pinnate, ovate, toothed

Description: The Wild Parsnip is a biennial plant that is 2-5 feet tall and occasionally branching. The alternate leaves are oddly pinnate with 9 hairless leaflets. The individual leaflets are 3 inches long, ovate or elliptic, and 2 inches wide with course teeth (usually more than 8). The yellow flowers (late spring thru mid-summer) form a compound umbel which is 3 to 8 inches across.

Look-alikes: Poison Hemlock (Conium maculatum) and Water Hemlock (Cicuta spp.) - a mouthful or a nibble of these is enough to kill you, if ingested.

Special Notes: The root of the parsnip is edible, but the shoots and leaves contain a photosensitive chemical which can cause a horrible reaction (phytophotodermatitis) if the substance gets on the skin and is exposed to sunlight (think chemical burns).

Common names: Wood-nettle, Canadian Wood-nettle

Scientific name: Laportea canadensis

Toxic parts: Stinging hairs on all parts

Duration: Perennial

Habitat: Moist rich woods, stream-banks, drainage areas

Height: 1-4 ft.

Bloom color: Yellow, or whitish green

Bloom time: June-September

Leaves: Alternate, ovate, serrate

Description: The Wood-nettle has plenty of stinging hairs. It is an annual or perennial which grows between 1 to 4 feet in height. The leaves are ovate, with sharply toothed margins and heart-shaped bases. The alternate leaves are up to 6 inches in length and medium to dark green in color. The leaves are hairy and the stems and petioles are covered in stinging hairs.

Look-alikes: Urtica spp.

Special notes: Most likely to be encountered along stream-banks or other moist wooded locations.

It can be difficult for some to memorize the eight itchy plants of the Appalachian Mountain region, and it is often even more difficult to remember what they all look like. There is no one rule for identifying poisonous plants, but in general if the plants have any of the following characteristics you probably ought to avoid them:

• Shiny leaves

• Hairy leaves (look at the underside) or stem

• Red rachis (think stem, twig, branch)

• Red hairy vine

• Milky sap

• Umbrella-like flowers

• Pungent smell

Here is the way I remember the Itchy Eight of the Appalachians:

These eight itchy plants you ought to avoid,

if you don't watch out you will be annoyed.

Steer clear of parsnip, and away from poison oak,

the creeping trumpet, and the ivy rope,

the ivy bush and the nettle of wood,

poison sumac, nettles and all will be good.

These eight itchy plants you ought to avoid,

if you don't watch out you will be annoyed.