Friday, June 21, 2013

Leaves of Three, Let It Be!

     Leaves of three, let it be!  Hairy vine, no friend of mine!  These are a couple of popular sayings I'm sure we all learned as kids, and that we all have in turn taught our own kids.  People grow up fearing and hating the fairly common native vine.  It is the subject of scorn, weeding and herbicide.  Yes, I am talking about poison ivy.  That unwanted scourge of a plant that can be a vine but can also become a shrub.  I have been on job sites that had poison ivy that was chest height and so thick that you could barely pass through it.  I have also see poison ivy vines that were so thick that I jokingly suggested that we count them for tree credit.  I would reason with the planning people that they had a diameter breast height that met their criteria and therefore should be counted (I might point out that these people are often not amused by this kind of a suggestion).

Early spring foliage
    Just what is it about poison ivy that is so awful?  It makes a great ground cover and often is one of the first plants to colonize a disturbed site.  It grows well in full sun but also can take a good deal of shade.  The leaves are actually quite pretty.  They are compound leaves with three leaflets per leaf.  In the early spring, they come out with a bronze color and they again turn red in the fall.  Plus the leaves have a nice shiny appearance.  They have pretty little white flowers and produce pretty little white berries that are highly favored by many kinds of birds.
     The real problem with poison ivy is a chemical called urushiol.  This is a clear oil produced by the plant.  It is most prevalent when the plant is broken or damaged, but is also present on the surface of the leaves and even the bare stems of the plant in winter.  This oil binds to the skin and to other items that come in contact with the plant.  For example, you could be careful to avoid the plant and then find yourself coming into contact with the oil because your dog ran through some and you reached down to pet him afterward.  You could have a towel or a piece of clothing brush through it and then become exposed when you accidentally touched that same piece of cloth.  You could even become exposed by breathing it in because someone placed it into a brush pile and burned the pile.
     Seventy five to eighty percent of the population have an allergic reaction to the substance and if you are one of those people, you are likely to fine that subsequent exposures cause more intense reactions.  So what do you do if you find it on your property?  First of all, don't panic.
     Poison ivy responds well to broadleaf herbicide treatments with chemicals like 2,4-D and Round-up.  It also responds well to being cut.  I usually suggest to people that they keep a separate set of shears to use for poison ivy cutting, but if you choose not to do that you are not sunk.  Simply make sure to clean your shears thoroughly with a detergent after each use.  As for the person doing the cutting; wear a watch.  Make sure that you wash within 45 minutes to an hour after an exposure and that you use a good oil-cutting detergent and scrub thoroughly.  Dishwashing detergent works well for this use.  The rash that you get a day or two after an exposure will let you know that you waited too long to wash or that you missed some of the exposure spots.  By the way, once you have washed the oil off, you cannot spread the problem even if the blisters that come up break.  That is a myth brought on by the fact that different quantities of exposure become a rash at different times.  Thus you might have become exposed all in one day but the rash might take several days to show up.
     Poison ivy is just a plant.  It is not something to be feared if you know how to handle it.  Wash in time and avoid the rash!

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