Take nothing for granted when you’re dealing with poison ivy in your landscape

As you’re cleaning things up in preparation for your fall re-landscaping improvements, you may encounter a harmless-looking plant growing among the rest of your groundcovers and shrubs.

This would be a good time to warn you about it. I might be able to save you a trip to the doctor.

Poison ivy germinates as a tiny seedling beneath shrubs or mixed in with your groundcovers.

It’s grateful for the good bed preparation, moisture and fertilizers it gets there, and before long it’s clambering up and over large parts of your landscape. You may tear into it to remove it without even knowing what danger lurks.

Let’s point out the facts

• Poison ivy (Toxicodendron radicans). (We don’t have poison oak – a sister plant and not a true oak – in this part of the country.)
• Vine to 30 to 40 ft. tall, also able to stand erect to 3 ft. tall in open areas.
• Each leaf consists of three leaflets originating from one stem (petiole) that attaches the leaf to the vine’s true stem. In simpler terms, when the leaf falls in autumn, the three leaflets fall as one unit.
• That gives rise to the old warning, “Leaves of three, leave it be.”
• Deciduous vine with dark green leaves that turn brilliant orange, red or yellow in fall. (Sadly, some of the prettiest fall color we have in North Texas.)
• Attaches to tree trunks, fences and buildings by twining, but especially by thick root-like appendages that adhere to the trunks.
• Important note: An oil contained in all parts of the plant’s tissues (leaves, stems, roots and even seeds) causes our skin’s allergic reaction. You must never come in contact with the oil, either by handling any part of the plant or by touching any tool that has been used to cut or remove it. The oil can even be on clothes that have been worn in the garden. My wife developed more than one rash washing my work clothes before we figured out how.
• We are all susceptible to poison ivy attacks at some point in our lives. Advancing years often make us more vulnerable. My PhD uncle who taught botany at Texas A&M instructed me as a child that someone who is coming down with a cold or other infection will be more susceptible. Point being: don’t be cocky. Always assume that the next poison ivy rash is going to be yours.

How to deal with poison ivy

• When you see young seedlings, just hit them with the corner of a sharpened hoe. Leave them to shrivel and die on top of the ground.
• When you have it growing in open territory where there is only turf around it (such as on a rural fence), apply a broadleafed weedkiller spray (containing 2,4-D) while it is growing actively. Spring and early summer are best, although you will still get some degree of control if you spray now. Do not spray when there is wind. Adjust the nozzle so you are applying large droplets and aim your spray directly at the poison ivy to avoid drift.
• When you have it growing up a tree trunk, and when it has formed large, even massive (wrist-sized) trunks of its own, cut the trunks at ground line with a long-handled axe. Wear long sleeves and long pants so that the oils won’t spew onto your skin. Make a second cut on each stem, this one 18 inches farther up on the stem. Use the head of the axe to pry to 18-inch “log” out of the way so it can fall to the ground where you can pick it up with a spading fork. Macerate the stump of the roots with the axe so that you can pour the broadleafed weedkiller onto it at full strength. Allow the herbicide to soak into the wood, but take care not to let excess run off and into the ground. Leave the top of the vine to wither and die in the tree. It will dry and gradually fall to the ground, probably over the winter. You can then pick up the pieces using your spading fork.
• Finally, when you have poison ivy growing within a groundcover bed or entwined within a shrub, and where spraying just won’t be possible, use long-handled lopping shears to cut it where it comes out of the ground. Usually you’ll be able to trace several stems back to one root system, and if you can sever the plant just above those roots you’ll be able to control it fairly easily. You can then apply the broadleafed weedkiller specifically to any regrowth that might come up. Again, leave the severed poison ivy stems on top of the groundcover or within the shrub until they dry and can be clipped and removed.

Plants that look like poison ivy

I can think of three fairly common plants that would fit that description.

• Virginia creeper. This is a rampantly growing vine that often co-exists with poison ivy. However, it has five leaflets, not three.
• Peppervine. This is a little native vine with much smaller leaves. You just have to learn how to distinguish it from the much larger poison ivy.
• Box elder seedlings. This is a tree that’s fairly common in our woodlands. It’s actually a poor-quality maple. As a seedling it has three leaflets, but it soon becomes obvious that it’s going to grow upright, not as a vine. But you really don’t want it anyway.

You can hear Neil Sperry on KLIF 570AM on Saturday afternoons 1-3 pm and on WBAP 820AM Sunday mornings 8-10 am. Join him at www.neilsperry.com and follow him on Facebook.

This story was originally published August 13, 2021 at 5:15 AM.