Now that our landscapes are fully green again, it is a good time to remind everyone who enjoys the outdoors to keep an eye out for poison ivy. Poison ivy is a native plant to Minnesota that causes most, but not all people, an itchy rash, swelling, or even blistering reactions. The plant will grow in either sun or shade, requiring all gardeners and outdoorsman to be on the alert as they are working or enjoying the outdoors.
Poison ivy is a perennial plant that often is a low growing plant between 1-2 feet tall, but can also be a climbing form and can be 3-12 feet or more in length. The old saying ?Äúleaves of three, let it be?Äù is definitely a place to start when it comes to identification. Leaves tend to be 2-7 inches long and 1-4 inches wide with an egg-shape. The leaves have a pointed tip and smooth to slightly irregular toothed edge. The leaves have a strong mid-vein running up the center with smaller veins evenly spaced at a 45-degree angle. Another helpful identifying characteristic is the leaves are glossy-green with a possible red-purple hint in early season. In fall, the leaves will turn yellow to red, surprisingly pretty. Also, in the fall some plants will produce a cluster of white to cream colored berries. The
plant spreads by its roots, above ground vines, or berry distribution.
Poison ivy is the only native plant on the Minnesota Department of Agriculture?Äôs Minnesota Noxious Weed Law under the Specially Regulated list. This means that it must be eradicated or controlled for public safety. Individuals are required by law to eradicate or control along property lines when requested by adjoining landowner. Control methods can be challenging as this plant should not be burned. The smoke and ash can carry the toxins and cause rash or lung injury if inhaled.
To control poison ivy look for herbicides containing triclopyr, this is often under labels specifically for poison ivy or a woody brush killer. Apply the herbicide directly to the leaves when the plant is actively growing and temperatures are 60-85¬?F. Read and follow all application and safety precautions on the label. Avoid spraying on windy days to prevent drift. Reapplication may be necessary a few weeks after initial treatment as poison ivy is a tough plant to kill and may resprout. Do not treat in the fall once leaves have begun to change color, simply wait till the following spring.
Early season poison ivy shows glossy leaves of three. Photo courtesy of Beth Berlin.