This is the first stop on the PGT tour. It's the demonstration garden just off the gravel driveway. You might check this out first to see a sample of plants blooming out on the larger prairie plantings. If you're not up to hiking further, it also gives a quick and easy view of some of the most showy of the prairie forbs and grasses.
Butterfly weed attracts fritillary and other butterflies when it's in peak bloom.