Poison Ivy Control
by Douglas Lantagne and Jim Kells
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Poison Ivy Control by Douglas Lantagne and Jim Kells |
Poison ivy (Rhus radicans) can be found in nearly any part of Michigan. It is known by several different names, such as three-leaved ivy, poison creeper, climbing sumac and poison oak. Its usual growth habit is as a slender vine running along the ground, or growing on shrubs and trees. The vines are capable of growing to several inches in diameter over a period of years. Poison ivy has three leaflets occurring alternately along the stem. Leaflets are usually smooth, but may be either a dull or glossy green. Leaf margins (edges) can be smooth, toothed, and/or lobed. Leaves on the same vine often have a number of color and leaf margin combinations. It is possible however, that all leaves on a vine will have the same general character. In general, however, there are no distinguishing characteristics to warn an unsuspecting individual that a vine is poison ivy.
The old saying of "leaflets three, let it be" should be remembered.
The flowers of poison ivy are typically inconspicuous and arise in clusters above the leaves. The berry-like fruit has a smooth waxy appearance and is grey to white in color. After the leaves drop in the fall, the berries are a distinct identifier of the poison ivy plant. As a vine climbs shrubs and trees, it produces numerous "aerial roots" to attach itself to the tree or shrub. The "aerial roots" give the vines a characteristic appearance often described as looking like a "fuzzy rope".
Poison ivy is often found along fence rows, railroad embankments, roadsides, transmission lines, in parks, nature preserves and many other wooded areas. Always be on the lookout for this vine in these areas regardless of the season. Poison ivy vines are poisonous the year around. There always the potential of transferring some of the oil present in the leaves, stem, fruits, roots or flowers of the poison ivy plant to the skin. It is this poisonous oil which causes the skin irritation identified with poison ivy. Although contact with the plant is normally the method of poisoning, an individual can also be poisoned by handling clothing, tools, objects or animals which have become contaminated with the oil.
The symptoms associated with poisoning usually appear within 12 to 24 hours but may appear in as little to 3 or 4 hours or be delayed for several days. The time span is dependent upon an individuals sensitivity, the amount of oil that contacted the skin, and the season. Spring and summer are the times of greatest potential for poisoning. Damaged leaves exude the oil, which is easily transferred to skin, clothes and objects. Symptoms are itchiness, skin inflammation, swelling and the formation of blisters.
Two general methods available for control of poison ivy are cultural and chemical. Cultural methods should not be attempted unless the individual is extremely tolerant to poison ivy. Individual sensitivity to poison ivy varies greatly. Natural immunity is originally present in all persons, but is reduced through time by contact with the poison. Therefore, care should always be taken when attempting to eradicate this plant. Individuals must also be careful when using chemical methods so that desirable plants are not mistakenly killed or injured. ALWAYS READ AND FOLLOW LABEL INSTRUCTIONS FOR ANY CHEMICAL USED AROUND THE HOME.
Burning is not a recommended method for eradicating this pest. Burning produces soot particles which carry the poisonous oils into the air. Individuals coming in contact with the smoke will experience severe cases of poisoning.
Poison ivy can usually be grubbed out when the soil is wet and there are only a few plants. Attempts to remove roots from dry soil are futile. Pieces of root remaining in the soil will sprout vigorously and replace the original plants. Plowing is also of little value since the disturbed root systems will sprout. Repeated cutting of the plant back to the ground surface will eventually starve the root system and the plant will die. However, repeated cutting increases the chances of exposure to the poisonous oil.
There are several herbicides which are effective in the control of poison ivy. They can be found in premixed or easily used formulations at local home and garden centers, and in garden centers at many local hardware and department stores. If a large quantity of any of these chemicals is required, contact your local County Extension office for the location of a local commercial chemical distributor.
There are numerous company and store brand names for the chemicals which effectively control poison ivy. The different brand names found will use one or more of the chemicals described in this publication. The major difference among the brands will be the amount of the active ingredient found in the product. The label on each product will list the name of the active ingredient and its concentration. If the chemical concentration in the product is sufficient to control poison ivy, it will be stated on the label. Always confirm, by reading the label, that any chemical you buy will control your specific pest.
If the label does not list the pest you want to control, find a chemical which does list your pest. Do not use a chemical to control a pest which is not listed on the label.
Several commonly used active ingredients effective in poison ivy control are:
Glyphosate The product is sold under the trade names of Roundup, Roundup concentrate and Kleenup. It is applied to the foliage of poison ivy but is translocated throughout the plant, including the roots. Glyphosate has no soil activity. It will kill or injure all plants contacted by the spray, including grasses. Applications near the foliage of desirable ornamentals should be made with extreme caution. Glyphosate should not be applied when rain is expected within six hours of application because its effectiveness will be reduced. After treatment, the vegetation should not be disturbed for several days. Remember, dead poison ivy still contains poisonous oils and should be handled with care if the soil in a treated area is to be worked. When glyphosate is the active ingredient listed on the label it is identified as Isopropylamine salt of glyphosate.
Amitrole Amitrole is sold under the trade names of Amitrol-T, and Weedazol. It is applied to the foliage and is translocated throughout the plant. It is nonselective, therefore it will kill or injure any plants to which it is applied. It also remains active in the soil for several weeks after application, therefore it is important not to use it near other desirable plants. The soil activity also prevents the planting of new vegetation for several weeks.
It should not be used in areas where food crops will be raised or animals grazed. When amitrole is the active ingredient listed on the label, it is identified as 3-Amino-1,2,4-triazole.
2,4-D This product is sold under many trade names and is often mixed with 2,4-DP to improve its effectiveness on woody plants. Weed-B-Gon Jet Weeder is a 2,4-D product for use around the house that can be purchased at most lawn and garden centers. It is not the most effective treatment for controlling poison ivy, but it does not kill grass.
Repeated treatments are usually required because the chemical seldom kills the root system. An ester formulation of 2,4-D is preferred to an amine formulation because it more easily penetrates plant tissue. However, the ester formulation is also more susceptible to drift and requires more care betaken to insure other desirable plants are not damaged by drift. The amine formulation is therefore recommended for use around the home landscape. Do not apply 2,4-D if rainfall is expected within 6 to 10 hours. When 2,4-D or 2,4-DP are the active ingredients listed on the label, they are identified as Diethanolamine salt of 2,4-Dichlorophenoxyacetic acid (2,4-D) and Diethanolamine salt of 2,4-Dichlorophenoxypropionic acid (2,4-DP).
Some plants are extremely sensitive to very small amounts of 2,4-D and 2,4-DP. Many plants can be affected by the trace amounts of these chemicals remaining in spray equipment after cleaning. It is recommended that a separate sprayer be maintained for 2,4-D and 2,4-DP applications. If the sprayer must be used for other purposes, rinse it several times with an ammonia solution. Follow the ammonia rinses with three rinses of clean water. All rinses should include spraying the solutions through the sprayer nozzle(s).
Triclopyr This product is sold under the trade names of Garlon, Redeem and Brush-B-Gon. It controls many annual and perennial broadleaf weeds including poison ivy. The best result occurs when the application is made on the foliage of actively growing vegetation. Protect desirable ornamental shrubs and trees and crops such as grapes, vegetables and flowers from any spray mist. Use a coarse spray to minimize drift. Do not plant trees in treated areas for a period of at least six months. Grasses are not affected by this chemical. Triclopyr is listed on the label as the active ingredient.
Other Products Other premixed combinations of herbicides may be available for control of poison ivy such as Crossbow, which is a mixture of 2,4-D and triclopyr. Although an herbicide may control poison ivy, not all herbicides are appropriate for use around homes and gardens. Please read the label before using any pesticide to insure that you will be using it properly.
The information contained on these pages is for educational purposes only. Reference to commercial products or trade names does not imply endorsement by the MSU Extension or bias against those not mentioned. These bulletins are public property and may be printed verbatim with credit to MSU. Reprinting cannot be used to endorse or advertise a commercial product or company.
If you have questions or would like additional information,
please contact
Dr. Karen
Potter-Witter, Professor, MSU Department of Forestry
