Anyone cleaning out overgrown areas or even just weeding a garden bed should beware — poison ivy may be growing among your plants.
Because poison ivy can cause a bothersome and sometimes serious rash, it pays to be able to identify this plant and avoid it, says LSU AgCenter horticulturist Dan Gill.
Poison ivy has a characteristic compound leaf consisting of three leaflets — hence the saying “leaves of three, let it be.” The leaflets are 2- to 4-inches long and dull or glossy green with pointed tips. The middle leaflet is generally largest. The leaf margins may be toothed, lobed or smooth and are arranged alternately on the stems.
New seedlings are easily overlooked. They may have a reddish tint to their foliage and will appear upright. As they get older, they will begin to vine and grow up into nearby shrubs or trees.
You can pull out poison ivy when the soil is moist, getting as much of the root as possible. Using rubber gloves, put the plants in a sealed plastic bag and throw it away. Be sure to wash your gloves thoroughly with soap.
You also can carefully spray the leaves with a systemic herbicide, covering nearby desirable plants to protect them. Wet the foliage of the vine thoroughly with the herbicide. Gill recommends herbicides with active ingredients glyphosate, triclopyr or a combination of dicamba and 2,4-D.
For larger established vines in trees or shrubs, cut off the vine a few inches from the ground and immediately treat the fresh-cut stump with the herbicide triclopyr. The vine in the tree or shrubs will die because it has no root system, and the treated stump will die because the herbicide is absorbed and translocates to the roots. But be careful. The dead vine will still contain the chemical that causes the rash, so handle it with gloves.
I have a very large oak tree in my backyard. Years ago I built a flower box around the oak made of 3-foot by 8-foot landscape timbers but never did plant anything. Can I now add some soil to the old flower box and plant some colorful plants?
It would not hurt to add a little garden soil or topsoil to the bed. It is not a good idea to pile soil up against the bark at the base of the trunk, so keep that to a minimum. — Dan Gill
Got a gardening question? Write to GardenNews@agcenter.lsu.edu