Poison ivy thrives very nicely in Idaho.

Your best protection is to watch where you're going and to recognize poison ivy when you see it.

Leaf color can be of interest in identification, but has no relationship to toxicity.

The toxic oil, urushiol, can be potent whether poison ivy leaves are red or green.

Let's follow it through a typical growing season and compare it to some other plants.

Poison Ivy April 29, 2004

Quarry trail on top of Table Rock, Boise, Idaho

These plants are starting to flower, but not all do. Don't rely on the presence of flowers to distinguish poison ivy.

Boxelder May 1, 2004

Crane Creek, Boise, Idaho

Boxelder has a pinnately compound leaf usually with three leaflets, very similar to poison ivy.

Boxelder is a species of maple and has winged seeds (samaras). Poison ivy does not. samara=safe

Boxelder can grow as a full sized tree.

Freestanding poison ivy cannot grow this tall, but poison ivy can achieve a lot of height as a climbing vine.

When you correctly identify boxelder, do not assume it is safe to go romping through the bushes there.

Poison ivy could occupy the same habitat as boxelder.

Black Cottonwood May 2, 2004

Boise River at Municipal Park, Boise, Idaho

Unlike poison ivy's compound leaf, black cottonwood always has a simple leaf. simple leaf=safe

Black cottonwood grows into tall trees, but its roots send up many shrubby-looking young branches.

Black cottonwood grows along Idaho's rivers, and it can be lush and abundant in places.

When you correctly identify black cottonwood, do not assume it is safe to go romping through the bushes there.

Poison ivy could occupy the same habitat as black cottonwood.

Poison Ivy May 5, 2004

Quarry trail on top of Table Rock, Boise, Idaho

Baby poison ivy plants are still sprouting.

Poison Ivy May 12, 2004

Quarry trail on top of Table Rock, Boise, Idaho

Poison ivy flowers are starting to bloom. There are other poison ivy plants that are showing no flowers.

Leaves are turning green. In moister habitats poison ivy can be camouflaged by other plants.

Some leaves show withering. Someone has been spraying herbicide here.

As you can see, today's weather was scattered rainshowers.

Poison Ivy May 12, 2004

Old Penitentiary to Table Rock Trail, Boise, Idaho

Nestled in the shade, these poison ivy plants have developed large, green leaves, but they are slow to flower.

Big sagebrush is harmless, but it may have some wicked companions.

Supported by the sagebrush branches, this poison ivy plant is approximately six feet tall.

Poison Ivy May 27, 2004

Lower Table Rock Quarry Trail, Boise, Idaho

This honeybee is gathering pollen from poison ivy flowers.

According to other websites, the pollen, and therefore the honey, does not contain urushiol.

Poison Ivy June 19, 2004

Quarry trail on top of Table Rock, Boise, Idaho

Where have all the flowers gone?

Many have withered and dispersed. Fertilized flowers have developed into berries like these.

I'm using "berry" in the colloquial sense. Technically the poison ivy fruit is a drupe.

Poison ivy berries contain urushiol. Humans should not eat them or touch them.

Birds are not bothered by urushiol. When the berries are ripe, birds will eat them.

Poison Ivy June 19, 2004

Old Penitentiary to Table Rock Trail, Boise, Idaho

This late-bloomer shows an earlier stage in the transition from flower to fruit than the one above it.

Poison Ivy July 8, 2004

Old Penitentiary to Table Rock Trail, Boise, Idaho

Like many other fruits, the green color gradually fades as the poison ivy berries ripen.

By the time the berries are ready for the birds to eat they will be creamy white.

Poison Ivy September 4, 2004

Ada County Boise River Greenbelt near The Weir, Boise, Idaho

The poison ivy berries are ripening and some leaves are starting to show autumn color.

Many plants still have green leaves, and many plants have no berries.

Poison Ivy October 6, 2004

Along the Boise River near The Weir, Boise, Idaho

Most poison ivy leaves are red. A few are still green, and some are turning brown and falling off.

Stands of poison ivy along the rivers that were camouflaged by cottonwoods during the summer

now become easier to recognize while the poison ivy leaves are red.

The poison ivy debris can become quite treacherous this time of year.

Although the dead leaves produce no fresh urushiol, chemical deterioration of urushiol is slow.

The area becomes heavily contaminated with the dead poison ivy leaves.

Poison Ivy October 9, 2004

Quarry trail on top of Table Rock, Boise, Idaho

This poison ivy sample shows smaller leaflets, abundant ripe drupes, and leaflets getting ready to fall off.

Virginia Creeper October 10, 2004

Boise River at Ann Morrison Park, Boise, Idaho

Virginia creeper is a common, climbing vine with palmately compound leaves.

There are usually five leaflets, but you may see some clusters of three leaflets.

The berries, if present, are green during the summer and turn blue when ripe.

Virginia creeper is harmless to touch, but do not become complacent when you have identified it.

Poison ivy can occupy the same habitat as Virginia creeper.

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