Discover the differences between poison ivy, oak, and sumac and how to care for rashes after Fountain City hikes. Life in Knoxville, especially in the Fountain City area, often includes time spent outdoors. Whether you are visiting Fountain City Park or walking trails around Sharp’s Ridge Memorial Park, it is common to brush up against plants without realizing it. Later, an itchy rash may appear and leave you wondering what caused it. Poison ivy ...