Information about poison ivy, oak, sumac and the skin rashes they cause
It has been an absolute rule for over a century: "Leaves of three, let them be."
Poison ivy has only three leaves (actually leaflets) in a group. And that is still true about 99.9999% of the time.
As spring rolls around, poison ivy is one of the first plants to emerge. Spring leaves are usually red, but many new leaves are red, so that's not enough to go on. See our ALWAYS-NEVER criteria for deciding if a plant is poison ivy.
When you cut down a tree, the sudden presence of sunlight encourages poison ivy vines to grow into the gap.
Here is a stump where the white snow highlights how the vines, with nowhere to climb, start reaching in all directions, looking for something else to climb up.
I had appeared on local media, talking about my favorite topic: poison ivy. After the show, a fellow contacted me to tell me about an abandoned barn in New Hampshire that he said I had to see.
When poison ivy climbs it grows thousands of tiny red root hairs to attach to the tree, wall, or other vertical surface.
When the leaves fall, many trees, fences, and buildings are revealed to be covered with masses of poison ivy vines. See how this very aggressive vine covers not only the poor tree, but also layers of other poison ivy, all scrambling upward in a nasty competition.
A research paper has just been published about the difficult invasive weed, Japanese knotweed. Seems that in some kinds of forests, this weed is taking over the understory and preventing new tree saplings from growing, thus threatening the future of these forests.
Up here in central New England, 2017 has had an extremely late first frost. (I wil forgo discussion of global warming to avoid the hate mail that such topics generate.)
I knew without getting close that this red vine was NOT poison ivy. How did I know for sure?
Because I took this photo in Turn, Italy, and there is no poision ivy in Italy, nor anywhere in Europe, for that matter.
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