Washington County
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Table of Contents:
Ivy and Oak
Poison ivy occurs in a wide range of habitats. It is in fencerows, along the road, railroads, tiff cuts, low and upland soils, wet woods, wooded slopes, cliffs and thickets. All provide suitable areas for poison ivy infestation. All things considered it is little wonder why this weed is so well adapted to Washington County.
The most recognizable feature of poison ivy is the leaves which are divided into three leaflets. There are two variations that occur in the area. The most common variation contains leaflets that are coarse and noticeable toothed. Rarer but just as toxic is the one that has leaflets that are without teeth around the leaflet margins. Some of us tend to call this poison oak when they are really referring to poison ivy.
Poison oak is not as common in the county as its cousin poison ivy. The best way to tell poison oak is its middle or terminal leaf which as a rounded blunt tip. Most of the poison oak in Missouri is located down around the Arkansas line.
Regardless of oak or ivy we have a pest which, according to the experts, adversely affects 85% of us. All members of the 'genus' produce what is known as urushiol the oil which is the guilt culprit that causes the skin rash. This oil can retain its toxic properties for several years after the plant dies.
The use of herbicides to control poison ivy/oak are usually used in late summer, early fall for best kill. Fall treatments should be timed before the foliage loses its green color. These chemical herbicides which give the best response are Arsenal which is used as a foliar spray, Garlon 3A which is used on a cut surface and Round-Up which is also used as a foliar spray. It should be noted that if one uses Garlon 3A as a foliar spray its effectiveness is only fair, but used on a cut surface the effectiveness becomes good. Both Roundup and Arsenal are rated good in their effectiveness against poison ivy/oak. The reason for fall treatments is so that the herbicides will travel along with plant's sugar to their root system for winter storage.
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University of Missouri Extension Washington County WashingtonCo@missouri.edu Site maintained by: Maudie Kelly, KellyME@missouri.edu Last revised: 05/05/08 |
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