The Whiteoak Sink area of Great Smoky Mountains National Park is a limestone basin surrounded by steep hills that comes alive as a natural botanical garden showcasing more than 30 varieties of native wildflowers in April each year. To help protect this fragile area from damage, please be aware of new visitation and group permit guidelines below and plan your visit accordingly. Groups with a minimum of 8 and maximum of 12 people are required to reserve a group hiking permit for one of two time slots available for a weekday; groups of 8 or more are prohibited from entering the Whiteoak Sink area on weekends. Individuals or small groups of 2-7 people do not need a permit.