The Prince William Wildflower Society is the VNPS chapter sponsor for the following VNPS Native Plant Site Registry locations.

Manassas National Battlefield Park

The meadows and the floodplain provide a diverse display of native plants. Protection of this flora is dependent upon proper management of the area. Recognition as a VNPS Registry Site emphasizes the importance of protecting these species, many of which were present at the time of the Civil War battles. Thus, there is human as well as natural history significance to this site.

Merrimac Farm Wildlife Management Area

This site was registered for the large stand of Virginia bluebells and other spring wildflowers in the Cedar Run floodplain, and also for the upland forest community in the northern and western portions of the property. This forest is one of the best stands left in Prince William with high species diversity, low levels of deer browse, little human disturbance for 50-80 years and few invasive plants. A portion of the forest is classified as upland depressional forest, a fairly rare plant community type characterized by a perched water table and wet-tolerant species.