Why it's easy to mistake poison ivy and Boston ivy for Virginia creeper

When it comes to fall color, you can't do much better than Virginia creeper (Parthenocissus quinquefolia). There are, however, two other vines that you might confuse with it: Boston (Parthenocissus tricuspidata) and poison ivy (Toxicodendron radicans).

This article will introduce you to all three species, with a spotlight on Virginia creeper.

But first, a vine overview.

Vine review

Vines are woody plants like trees and shrubs. Unlike these other two categories, vines cannot stand on their own. A few vines try to grow upright, but they're not very good at it.

So, they find ways to stick to tree trunks, walls, and other vertical surfaces. They have different ways of doing this. Some simply twine around supporting structures such as tree trunks, fences, arbors, or trellises.

Poison ivy and hydrangea use aerial rootlets that grow from the sides or their stems. These tiny roots adhere best to rough surfaces, such as tree bark or stonework.

This brings us to Virginia creeper and Boston ivy. These vines use disk-shaped adhesive pads called hold fasts. Hold fasts are not too picky about what they will stick on. Smooth surfaces will work just as well as rough facades.

Virginia creeper

Virginia creeper certainly isn't limited to Virginia, but it does creep. This vine grows across eastern and central North America. This native plant is not habitat-specific. It grows almost everywhere, including ravines, swampy forests, thickets, fencerows, hillsides, roadsides, and up the side of your house or garage.

Besides Virginia creeper, it is also known as false grapes, American ivy, five-leaved ivy, thicket creeper and woodbine. The common name woodbine is sometimes used to refer to other species in this genus. To avoid confusion, I'll shy away from woodbine.

Now, five-leaved ivy is not a bad alternate name. This vine has palmately (arranged like the fingers around your palm) compound leaves with five leaflets - most of the time. On occasion, it will just have three or as many as seven leaflets.

It is the leaflets that prompted me to write this article for an autumn newsletter. The leaflets range are elliptical with toothed margins. The middle leaflet is largest, up to six inches long and two-and-a-half inches wide. In the fall, they turn a bright red to maroon color. In spring, the newly emerging leaflets are also red before turning a rich green color.

A glass of 'vine?'

False grapes is also not too bad a name for this ivy. It produces small bluish-black berries that ripen from August to October. These berries are food for a variety of bird species such as bluebirds, chickadees, thrushes, vireos, woodpeckers, crows, flycatchers, catbirds, and sparrows. The vine's thick foliage provides many birds with a place to build a nest or hide from predators.

Mammals that dine at the creeper cafe would include foxes, rabbits, skunks, chipmunks, and squirrels. For the record, Virginia creeper berries are not poisonous to humans. Be advised, though, the fruit does contain oxalic acid, which can irritate your stomach and kidneys. It doesn't taste very good either.

Now, that was just the warm-blooded wildlife. Let's move to the insects. The caterpillars for, at least, four species of moth dine on creeper leaves: eight-spotted forester, Virginia creeper sphinx moth, Achemon sphinx moth, and the grape leaf skeletonizer.

Since I have a degree in forestry, I can't pass up the eight-spotted forester. The larvae are marked with black, white, and orange rings. Besides chomping on the leaves, they will also eat tendrils and growing stem tissue.

If disturbed, they will vomit an orange fluid or spin a line of silk, called a belay line, to quickly lower themselves to a different perch. Other caterpillars, such as inchworms, produce belay lines as well.

Vine confusion

Look at the photo which shows Virginia creeper and poison ivy vines growing, side by side up the same tree trunk. You can see how folks might confuse these plants when they grow in such proximity.

You'll note that creeper leaves, on the left side of the photo, are edged with teeth. The poison ivy leaves, on the right side, can be smooth or just have a notch or two.

Leaf tips won't help in the winter when the leaves are under the snow. If you touch the stem of poison ivy, you might still suffer an allergic reaction. Remember that poison ivy hangs on to tree trunks with red aerial rootlets, while Virginia creeper uses those disk-shaped adhesive pads.

These aerial rootlets are red year-round. Of course, one might argue that if you are close enough to see the rootlets, you're too close.

The Ivy League

Look at the photo depicting a vine growing on steps a short distance from where I am sitting. That can't be poison ivy, can it? Nope, this is a somewhat aberrant example of Boston ivy also known as cottage ivy, or Japanese creeper.

This hardy native of Asia is a close relative of Virginia creeper and has been planted to decorate walls, buildings, trellises, arbors, and fences. In the Northeast, Boston ivy gave rise to the phrase Ivy League. I'm willing to bet you have seen this vine.

Like Virginia creeper, Boston ivy has dark berries and the leaves turn a rich red or burgundy in the fall. Usually, the leaves are toothed and have three lobes rather than three leaflets. But, as the photo illustrates, it can be confused with poison ivy and Virginia creeper.

To plant or not to plant

Believe it or not, a 19th century British explorer brought some poison ivy home to decorate his garden. I doubt any of you will be doing that.

The other two vines can add color to your yard, but you should take care when planting them. They can overwhelm small trees. The thick creeper leaves can block sun from reaching the tree's leaves. Of course, they do well on trellises and arbors.

Virginia creeper and its cousins can also be quite useful as ground cover. If you have a stump you would like to hide, let Virginia creeper or Boston ivy cover it up. Also, if you have an area prone to erosion, Virginia creeper makes a great ground cover (see first photo).

You do need to be careful with walls on buildings. Vines may cause damage to wood siding and stucco. The creepers can also find their way into loose joints, gutters, ventilation louvers, and shutters. Timely pruning can minimize these potential problems.

According to legendary architect Frank Lloyd Wright, there is an appropriate time for planting vines near structures: "The physician can bury his mistakes, but the architect can only advise his client to plant vines."

• Mark Spreyer is executive director of the Stillman Nature Center in Barrington. Email him at stillmangho@gmail.com.