The best way to avoid problems with poison ivy is to learn to identify it.
Since poison ivy in present in a vast portion of North America, it's likely you'll
run it to it at some point if you live in areas it grows or if you travel to any.
There are only three things that are absolutely true about poison ivy identification:
(Note that the following criteria applies
to poison ivy but not necessarily poison oak or sumac.)
1. Poison ivy always has 3 leaves
Poison ivy never
has more than 3 leaves on each stem. If you see 5 leaves, 7
leaves or any number higher than 3, you're not looking at poison ivy
(however, you could be looking at poison oak, which is also harmful).
If you see a group of 3 leaves on a vine but also see a group of 5
or more leaves on the same vine, then that can't be poison ivy.
You're most likely looking at
Occasionally a poison ivy leaflet drops off
and you'll have 2 in a bunch, but never more than 3.
Getting technical: The correct way to describe poison ivy
is to say each poison ivy leaf consists of 3 leaflets.
The picture at the right shows one poison ivy leaf (circled in orange).
That leaf consists of 3 leaflets. Whether you call them leaves or leaflets,
just remember there are always 3.
2. Poison ivy does not have thorns
blackberries, and other bramble-type plants look very similar to poison ivy
because they have 3 leaflets and even may have leaf "notches" like poison ivy can have,
but they have thorns on the stems. Poison ivy stems are either smooth or hairy, but never thorny.
The picture to the right is NOT poison ivy because the stem is thorny.
I believe this is a wild raspberry bush since I saw others in the vicinity
that were bearing fruit.
Click the photo to see a larger version that clearly shows the thorns.
In the full size photo, look in the lower right corner... that IS poison
ivy hidden in with the raspberry bush. Look out for that sort of thing
because poison ivy frequently grows intermixed with other plants!
3. Poison ivy leaves are arranged alternately on the stem
means each leaf or group of leaflets doesn't grow right across from each other and usually
alternate sides of the stem (in other words, as you're looking at the plant, one set of leaflets might be on the left side, the next set of leaflets on the right,
the next on the left, etc.). The poison ivy picture on the right shows alternate leafing well.
Click on the photo to see a larger version.
The other type of leaf arrangement is called "opposite".
Leaves that are arranged opposite from each other are right across
the stem from each other. Young Box Elder trees are often mistaken
for poison ivy, however,
Box Elder leaves are opposite.
Poison ivy leaves are never opposite - they are always alternate.
The diagram below shows more about the difference between
alternate and opposite leaf arrangement:
Alternate Leaf Pattern:
Alternate leaves only have a single leaf (or group of leaflets) attached at
one location on a stem, often the leaves alternate from one side to the other
as they go along the stem or they may be in a spiral pattern.
Poison has three leaflets occurring alternately on the stem.
Opposite Leaf Pattern :
Opposite leaves refer to two leaves being attached at
the same location on a stem, but opposite each other on
either side of the stem. Box elder and young maple trees have
Uncertain Identification Criteria
Now that we've
learned the three hard and fast rules, here is other popular criteria for poison
ivy identification. However, you can't completely count on these things to
ALWAYS be true, so don't ever count on them exclusively.
Poison ivy stems are not always red.
Sometimes yes, but they can also be green.
there is a red dot in the middle of the three leaflets, but not always.
Some poison ivy plants are entirely green with no red any place on any of
stems have "hair" on them (dark tendril-like hairs).
Sometimes yes, especially when the plant is trying to climb something.
However, stems can also be slightly fuzzy or even completely bare.
The stems can also be woody.
leaves are not always shiny and/or red.
Leaves can be light green, yellow green, dark green, orangish,
reddish, or even brownish. Leaves might be oily-looking or they may be dull.
Sometimes they can even be multi-colored (green with yellow or brown spots) if the
plant has been out in hot sun for too long.
have a notched pattern, but others do not.
The picture at the top of the page (showing leaflets) shows a plant with notches, but the
photo showing alternate leaf arrangement does not. Although notches are common,
leave sides (margins) might be smooth or slightly toothed. Leaves can be
short or long, thin or fat, large or small, curly or straight. Worse yet, leaves can look
very different but still be on the same plant.
Poison ivy has white (or very pale yellow) flowers and white berries.
This is true, but the plant might not be in bloom or have berries at the moment.
Poison Ivy Habitat
Poison Ivy can grow practically
anywhere. It can be in deep woods to full sun fields to the beach. It grows on telephone poles, signs, fences and trees,
or it can be a free-standing plant or bush. It has no soil preferences and can
grow in anything from dry, sandy, clay-filled soil to dark, rich soil. It
often creeps along the ground. So long as there's some kind of soil, sunlight and water, it will grow.
It is not limited to wild areas, either. Poison ivy is fond of gardens and fence
lines in your yard. It likes to grow against the house or garage or inside of
your bushes and hedges. It will be hidden in with your other
About the only place poison ivy usually does not grow (at least not for very long)
is in mowed lawns. That's because mowers cut off the leaves. Poison ivy needs its leaves to
make food through photosynthesis. Without food, it will die.
This is why you almost never see it growing in the middle of a lawn.
However, if you only weed whack a fence every couple weeks, poison ivy can move right
Totally off the wall: I worked as an environmental educator for 5 years and had at least one live,
potted poison ivy plant in my office for show and tell.
It had a nice sunny window in my office, so it had light and water... really all it needed.
However, keeping the plants taught me two things: it does not like to live in pots
and it does not like to be overwatered. I managed to kill (unintentionally) every plant I had.
So, there's your solution: pot it and overwater it. You'll kill it, guaranteed.
How to Kill Poison Ivy
An almost guaranteed way to kill ivy off in the yard is to use a spectrum herbicide. However, be careful,
because it will kill everything, not just the ivy.
I'm not a fan of chemicals at all, so I prefer to go with a different method: put vinegar on the
leaves and the sun will help kill it off. However, you usually have to do that
more than once to be effective. Again - be careful because vinegar will also kill everything else it
I conductied an experiment with this method and had good results.
Of course, you can't and shouldn't carry weed killer on a photo shoot.
Even if you used it, it would not work instantaneously. A better idea
is to just learn to avoid poison ivy.
By the way, NEVER burn poison
ivy plants or vines! The urushiol oil can spread in the wind, get into your lungs
(or someone else's), and cause a very severe reaction.
Other Poison Ivy Topics: