Poison Ivy Scouting

Poison Ivy Growing Among Woodsorrel

Whenever I take a walk around our house, I keep my eyes open for poison ivy. In the past couple weeks it seems to have awoke from its seasonal slumber and is ready to take off. The sooner you can control poison ivy the better. In order to control it well, it is important to understand this persistent plant.

The old saying “leaves of three, let it be” has been most helpful for me over the years to keep from getting confused between poison ivy and other look alikes. Poison ivy is a climbing woody vine that loses it’s leaves each winter. Leaves are egg shaped with three leaves per petiole that may be toothed, lobed, or entire. Poison ivy attaches to trees and rocks with aerial roots, which may have a hairy, fibrous appearance. Leaves may take on a reddish hue late in the season. It reproduces by creeping stems, roots, and seed transported by birds. Poison ivy can thrive in many areas that other plants do not.

All parts of the plant contain resins that cause allergic reactions for most of the U.S. population. These resins cause issues if burned, directly touched, or indirectly transferred from one surface to another. Resins are continually present on the leaves, stems, and roots, even in the winter.

Poison ivy is often confused with Virginia creeper, which is a creeping and trailing vine that secures itself to objects with specialized stems call tendrils. Virginia creeper has 5 leaflets, instead of three and is not poisonous. Poison oak is another common mix up. Poison oak has three leaflets, but the leaves look very similar to a classic oak leaf. The lobes have blunt tips and hairs on both the top and bottom of the leaf. Poison oak is not a creeping weed, but rather grows upright from the soil surface. For this plant the “leaves of three, let it be” statement still applies.

Poison ivy and poison oak are responsive to glyphosate, triclopyr, and 2, 4-D herbicides, which are commonly used in poison ivy killers. Always follow the label when using a herbicide and wear adequate protective gear while handling!

     Virginia Creeper

Poison Oak (Photo Credit-School of Forest Resources & Conservation – University of Florida)

Poisonous Plants

Whether it is in the pasture or in your back yard it’s that time of year again where poisonous plants are around and can cause trouble if not properly identified. Some of the most common poisonous plants that affect us in our backyard and surrounding areas are poison ivy, oak and sumac. All contain urushiol, which is a plant oil that can cause a severe skin rash. However, identification of these plants can be difficult as they might be confused with other non-poisonous species.

Poison ivy grows in shady or sunny locations and may be either a woody shrub or a vine that can climb up to 150 feet tall! All parts of the plant, including the roots contain urushiol at all times of the year, even when bare of leaves in the winter. Leaf forms are variable among plants and even among leaves on the same plant however; the leaves always consist of three leaflets. Leaflets can be 2-6 inches long and may be toothed or have smooth edges. The stem that is attached to the terminal leaflet is longer than the stems attaching the other two. Fruit of the poison ivy is always in clusters on slender stems between the leaves and woody twigs. They are round and grooved with a white, waxy coating and are attractive to birds and are an important food source for deer. A common poison ivy look-alike is Virginia creeper. It is also a trailing vine but it has 5 divide palmate leaflets. It also has blue-black berries.

Poison oak is a low growing shrub that can be about 3 feet tall. It is located in dry, sunny locations and not usually in heavy shade. Poison oak displays lobed leaves, which give it the appearance of an oak leaf. The leaves are generally about 6 inches long and the middle leaflet is alike lobed on both margins and the two lateral leaflets are often irregularly lobed.

Poison sumac leaves consist of 7-13 leaflets arranged in pairs with a single leaflet at the end. Leaflets are elongated, oval and have smooth margins. The sumac plant also has reddish stems.

There are numerous other plants, trees and shrubs that can be poisonous to humans and livestock as well. If you spot something that you aren’t familiar with, please feel free to bring it to the office for identification. However, if you are having a reaction, please seek the advice of your doctor.

Poison Ivy                               Poison Oak                                 Poison Sumac

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