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Poison Ivy (PI) – Poison Oak (PO) – Poison Sumac (PS)

When looking at a map of the United States, I see almost all of us have the potential to have at least two of the woody poisonous plants. The two most common, PI and PO both have leaves in a cluster of 3. The leaves may be very waxy and glossy or dull and flat, making identification harder.

Western PI and Eastern PI. Both occur over a large part of the U.S. It can be found as a low-growing shrub, a vine along the ground or a vine that climbs to the top of the tallest tree. PI has woody rhizomes which can make it hard to control, it also spreads by seeds.

Western PO is also known as Pacific PO, occurs as a woody shrub or a vine that loses its leaves in the winter. Birds generally help in the spread, by eating the fruit and depositing in a new location, where over time a single plant may spread over a larger area.

Eastern PO is also known as Atlantic PO, is generally found as a short shrub up to 4 foot. It is found in sandy or drier locations such as open woodlands and pine areas, more common along the forest edge.

Finally, PS grows in very wet or flooded soils such as; swamps, bogs, wetlands and the shore of lakes and streams. It grows as a shrub up to 6 to 15 feet tall. May be the MOST poisonous of them all.


The first type of control is hand pulling, grubbing, or hoeing. This may be effective, but you must get all portions of the underground rootstock. Don’t forget to wear gloves and protective clothes and don’t rub your eyes!

First, you can prune the plants back and apply Brush Killer Stump Killer or Cut Vine & Stump Killer, undiluted to the stumps within 45 minutes. This is the only way to treat plants vining on other, desirable plants. Triclopyr 4 is also available in ½ gallon, gallon and 2½ gallon as well.

For selective control in turf, or around desirable plants, you can spray the Brush & Stump or Triclopyr 4. In turf only, the Triclopyr + D is a little more effective with the addition of 2,4-D, available in the same sizes as above.

For non-selective control, spray with KillZall, which has 2 surfactants and will stick better than most other chemicals. For a beefed-up version and in wet locations, use KillZall Aquatic. With this chemical and the others, add Spreader Sticker to the mix to help it adhere and penetrate those waxy leaves.

Contact us or stop by to talk to the experts at The Big Tool Box and Highlands Garden Center in Parker and Centennial to rid your property of poison ivy and poison oak.