Of Poison Ivy and the Woolly Adelgid
By Joshua Sweet
Poison ivy concerns many national park visitors each year.
This menacing plant, which is not actually poisonous, can cause an allergic reaction when it comes in contact with human skin. The source of this allergy is an oil on the plant known as urushiol.
The first step to avoiding poison ivy is to be able to correctly identify it. The plant has three leaves and these leaves have serrated “thumbs.” In addition, be on the lookout for a dim red spot where the leaves meet.
Poison ivy is able to grow as a vine and will develop thick, hairy roots.
Following outdoor pursuits in areas where the plant is present, wash your body, clothes and gear with a poison ivy cleanser. If left untreated, oils can remain on your belongings, and even pets.
If a rash occurs, do not scratch the area, and attempt to keep it cool and dry. Also be sure to check the area near your firewood and campfire, as burning poison ivy can cause inflammation of the airway.
Only mammals are allergic to the urushiol oil, but not everyone will see a reaction after coming in contact with the plant.
It is possible to develop an allergy to the plant following repeated contacts. If a severe reaction to poison ivy develops, contact a licensed physician.
‘What is happening to the hemlock trees?’
The hemlock trees along the Blue Ridge Parkway have been plagued by an insect known as the woolly adelgid.
This unwelcome pest is considered an invasive species and originated in Europe. The insects’ feeding pattern disrupts photosynthesis, eventually killing the tree.
The effects of the woolly adelgid can be seen throughout the parkway. Other European parasites were introduced to combat the woolly adelgid, but have failed to make much of an impact. This insect feeds on the tree through a slim mouthpiece and remains in place covered with white wool.
Other trees have also been infected, including fir and spruce. After becoming infested, these trees will usually die in less than three years time.
While hiking along the trails, you may come across trees marked with a blue dot. These trees have been treated with an experimental treatment in hopes of solving the adelgid problem.
If you have a question about the Blue Ridge Parkway or its flora and fauna, email (email@example.com) All of your questions will be answered. Two will be featured next week. See you on the trails.
Dear Naturalist is a weekly column devoted to the questions you have about our natural world.
Ranger Joshua Sweet is an interpretive park guide for the Blue Ridge Parkway at Linville Falls. He is a “Leave No Trace” master educator and a wilderness first responder. Before moving to North Carolina, he lived in Northern Minnesota, where he taught environmental science to fifth- and sixth-grade students.