- Urushiol is the oil present in Poison Ivy that causes the rash.
- Urushiol is present in all parts of the plant but especially in the sap.
- Urushiol can cause a rash from 1 to 5 years after a plant has died.
- The amount of urushiol that covers the head of a pin can cause a rash in 500 people. The stuff is potent.
- Poison Ivy can grow as a ground cover, a shrub or a vine. We are concerned with the vine in this article.
- Using a chainsaw on Poison Ivy in the winter can release sap which makes a rash more likely. This is worse on warm days where there is more sap rise.
So, how do you tell the two apart? This is actually easy once you know what to check. Look at the aerial roots on the vines of Poison Ivy and Virginia Creeper. They resemble hairs on Poison Ivy but are plumper on Virginia Creeper and are about the size of a pencil lead. (Ward Upham)