Wetlands in the northern part of Wolf Trap have a slightly different feel than the rest of the park. The lush vegetation of this micro-environment exudes the hot and humid atmosphere typically associated with early Summer.
You can reach them if you follow the Wolf Trap creek downstream from the pond bench (along blue arrows). If you keep to the left, eventually you end up at the East Lot, which is another good entry point (the trailhead is just behind the bridge over the creek).
— honza —