Stefni Krutz Tuesday, 14 August 2018
I am reluctant to be indoors when the weather is warm, so I did some bird watching on lunch break, but also taking time to notice the plants that grow here. I’m a Texas native, and while many of the plants are familiar here, some are not.
As a forester my plant ID skills should stay sharp, so I quiz myself as I look around. Seeing a specimen deserving of a closer look, I stepped into the taller weeds and…stopped immediately. Poison ivy alert!
In front of me were three pinnate leaves - leaves of three! But the plant looked wrong for poison ivy, more like a tree than a vine. And the leaves were opposite one another instead of alternating. Looking at other nearby trees, I saw more leaves of three. Jenkies, it was boxelder!
Boxelder (Acer negundo) is the most widespread of the maples, ranging coast-to-coast and from Canada to Guatemala. It is often referred to as a “trash tree” because of its poor form, short life span, and lack of monetary value. However, it is highly adaptable - as its large range suggests - and grows quickly, which is why it is planted to stabilize soil and control erosion. Like other maples, its flowers are popular with the bees, and its seeds can remain through the fall and into winter, making it an important food source for wildlife.
A clump of box elder trees
Now let’s talk about poison ivy. New York is home to two species of poison ivy: the eastern (Toxicodendron radicans) and the western (Toxicondendron rydbergii). Eastern poison ivy can be a vine or small shrub, while western poison ivy is only a small shrub. And both have leaves of three: two leaves on the side, with the center leaf having a longer stem than the other two.
Luckily I did not stumble across poison ivy that day. I’m not yet sensitized to the urushiol oil that causes the rashes and itching, and sensitization happens with repeated exposure, so I steer clear of poison ivy.
Some people can be resistant or even immune to the oil, but few people truly are. Once I was with a field group where one of our members swore he was immune and was going to eat a poison ivy leaf to prove it to us. We were able to talk him out of the demonstration but he will be completely convinced to his immunity until the day he gets his first rash.
To get more familiar with poison ivy and other dangerous plants, check out this factsheet.