Annual Poison Oak Show at the St. Charles Saloon in Columbia State Historic Park. Aren’t you just itchin’ to participate? This event is like a traditional flower show, except all entries must include poison oak! Some of the categories are the best arrangement of poison oak, the most original poison oak dish (with recipe), the best photograph of poison oak, and the best photograph of poison oak rash (or in person). 10 am for entries, judging at 1 pm.