- On this preserve, dramatic basalt cliffs, canyons and tabletop mesas support unusually well preserved examples of eastern Washington’s shrub speckled grasslands known as shrub-steppe. A diversity in soil and habitats on the preserve provide sites for six distinct plant communities identified in the State of Washington Natural Heritage Plan. Threetip sage brush, big sagebrush, bluebunch wheatgrass, needle-and-threadgrass, and Idaho fescue are the main species represented in these habitats. On top of the castle, alkali-tolerant wildflowers and grasses grow in bands around a shallow, seasonal (vernal) pond which gradually dries up during summer.