We're all familiar with the adage “leaves of three, let it be.”  And we all know that this refers to Poison Ivy, one of our most irritating (quite literally) native plants. 

The urushiol oil from the plant is one of the most common allergy problems in the U.S.  The oil can stay active for 1 to 5 years on any surface, including dead plants or vines, so this adage reminds us to stay clear of Poison Ivy plants and vines.  

But there is also another reason to “let it be.”  Poison Ivy, if growing in the right place, can be quite valuable.  For instance, did you know that over 60 species of birds rely on the fruit of Poison Ivy as a primary food source in the fall and winter months?  The fruits provide an essential lipid (fat) source to migrating and over-wintering birds that helps them survive during periods of stress and low food availability.  We have seen Yellow-rumped Warblers, Downy and Red-Bellied Woodpeckers, Wild Turkey and Eastern Bluebirds all consume Poison Ivy fruits while over-wintering in our area.

Poison Ivy is often confused with other three-leaved plants.  One way to tell the difference is to look closely at the leaves.  The middle leaflet has a visibly longer stem than the two side leaflets.  The white berries are another aid to identification.  And in regard to the vine, it is always hairy, unlike wild grape or Virginia Creeper. 
  
We recommend leaving those leaves of three be, if they are growing in the more natural areas of your property, and observing what species of wildlife consume the fruit.

Image