If you grew up in a rural area, you’ve probably heard the old adage, “leaves of three, let it be.”
This brief, descriptive warning is intended to keep you from touching or brushing against the poison ivy plant. The reason for this warning? The oily sap on the plant’s leaves, called urushiol, often causes an allergic reaction and rash.
If you didn’t grow up near the woods, it may surprise you to learn that poison ivy can grow in sidewalk cracks, vacant lots, and other nooks and crannies throughout cities, beach towns, and suburbs. In fact, poison ivy can be found in every U.S. state, except Alaska and Hawaii.
So, in addition to memorizing that age-old rhyme, here’s what you need to know about identifying — and avoiding — poison ivy.
Poison ivy looks differently during each phase of its growth cycle. Here’s what to look for in all seasons.
In the spring
When poison ivy starts to blossom in the spring, its leaves may be red or a mixture of red and green. Some people confuse these early blossoming leaves with fragrant sumac, a shrub that grows red leaves.
Green flower buds will start to appear in spring and slowly open, turning white.
In the summer
As the weather gets warmer and poison ivy continues to mature, older leaves will become completely green, but new leaf growth will continue to start out as red.
Poison ivy’s off-white, small berries may be hidden by leaves but you can see them growing on stems if you look closely.
The leaf size can vary from small to large.
Variances in shape will also be apparent. In some instances, poison ivy leaves may appear deeply ridged along its edges, mimicking other plants such as Virginia creeper or oak leaves.
Individual plants may grow quite high. Unless it’s removed, poison ivy vines may overtake outdoor structures. It can also spread in large areas on the ground.
In the fall
As the days shorten and temperature drops, poison ivy will change color to bright orange, yellow, or red. It’s quite beautiful during this time, but as dangerous to touch as it is during warmer weather.
In the winter
In cold weather, poison ivy leaves turn deep red, then shrivel and fall off.
The roots can become or remain exposed and look either hairy or completely bare. The roots, which can also cause a rash, can continue to lengthen and grow by attaching themselves to trees, walls, or ground cover.
You may be able to spot poison ivy’s exposed white berries on its bare branches during this time.
During winter, you may see bare and slender poison ivy branches poking out of the snow.
Identify poison ivy online
PoisonIvy.org has photos of poison ivy varieties throughout the seasons that you can view. You can also upload a photo you’ve taken and find out if it’s poison ivy or another look-alike.
Like poison ivy, poison oak contains urushiol, the oil that causes allergic reactions to occur.
Poison oak very closely resembles poison ivy. It usually has three leaves but can have as many as seven leaves per cluster. These leaves can be green, red, or a combination of both.
Poison oak’s leaves are sometimes more deeply ridged along their edges than those of poison ivy. They may also have a textured, slightly hairy appearance.
Poison sumac also contains urushiol and shouldn’t be touched.
Unlike poison ivy and poison oak, this plant’s leaves always grow in larger clusters of 7 to 13 per stem. Poison sumac doesn’t grow as ground cover. It’s much taller than poison ivy and resembles a shrub or tree.
If poison ivy is growing in your backyard or around your home, you’ll want to get rid of it safely and quickly. The don’ts of poison ivy removal are as important to note as the do’s.
- try to remove poison ivy leaves, branches, roots, or stems with your bare hands or any exposed skin, even if you haven’t had an allergic reaction to it; repeated exposure can trigger allergic reactions
- burn poison ivy, as urushiol can be toxic if inhaled in smoke, steam, or vapor
- pull poison ivy plants out of the ground and dispose of in sealed plastic bags, being sure to get the entire root so it doesn’t grow back
- dispose of or wash your clothes, hats, and gloves in very hot water and shower immediately
- kill poison ivy plants by making a nonchemical spray of vinegar, salt, and dishwashing liquid (see below)
Make a nonchemical spray
- Dissolve 1 cup of coarse salt in 1 gallon of white vinegar.
- Heat the mixture until the salt liquefies.
- Add 8 to 10 drops of dishwashing liquid.
- Spray or pour directly on all poison ivy plants. This mixture will kill any vegetation it touches, so keep it away from the plants you wish to protect.
Poison ivy is a poisonous plant that causes a red, blistered, extremely itchy rash.
You can’t catch poison ivy from another person, but you can get it by touching or rubbing up against something that has come into contact with the plant, such as a pet, or clothing.
Urushiol, the oily sappy irritant
Urushiol, the oily, sappy substance which causes an allergic reaction and rash, can stay on clothing and other surfaces for two years or longer unless it’s washed away.
Urushiol is produced by every part of the poison ivy plant including its:
Can irritate your skin in all seasons
Poison ivy is associated with spring and summer because it’s more abundant at that time. However, don’t make the mistake of thinking that poison ivy only irritates your skin when it’s in full bloom.
Most people are highly allergic to this plant throughout its entire growth cycle and in all seasons, including winter.
Types of poison ivy
There are two types of poison ivy, Eastern and Western. Despite their names, you can find both scattered throughout the country, since they interbreed. Physical characteristics of the plant to keep in mind include:
- Both types of poison ivy look similar and have three-leaf clusters on slender stems.
- Their leaves can vary in color from green to red or orange. They can also vary in shape.
- The tips of the leaves may be pointed or rounded. They may have jagged edges or smooth ones.
- Poison ivy plants grow berries of a dull, white color. They also grow very tiny, white flowers.
- Eastern poison ivy can be found as a ground vine and as a climbing vine. Western poison ivy grows only as a ground vine.
- In some instances, poison ivy can grow so high and full that it looks like a shrub or small tree.
- A poison ivy rash may appear anywhere from 12 hours to several days after you’ve been exposed to urushiol.
- If you know you’ve been in contact with poison ivy, remove all articles of clothing while wearing disposable gloves, and wash your skin immediately.
- Take an oral antihistamine, to reduce your allergic response and hopefully lessen itching.
- Gently apply hydrocortisone cream or calamine lotion to the affected areas of skin.
- Continue to soothe your skin with colloidal oatmeal baths or compresses.
- Avoid scratching.
- If your symptoms are severe, see your doctor.
Poison ivy usually has leaves of three, but that’s true of other plants as well. A good rule to follow is: If you think it may be poison ivy, stay away!
You can be exposed to urushiol, the oily substance in poison ivy that causes a reaction, by touching any part of the plant or by coming into contact with something that has urushiol on it.
Poison ivy can cause an allergic reaction and itchy rash at all times of the year, not just spring and summer.