After a somewhat disappointing spring for wildflowers in Mojave Desert portions of the northern Owens Valley, things are looking pretty good for the eastern Sierra slopes and southern Great Basin in Mono County.
I went for a hike up McGee Creek near Crowley Lake this weekend and I was pleasantly surprised with the displays of color. Some of the common plants flowering include; bitterbrush (Purshia tridentata), mule ears (Wyethia mollis), hawksbeard (Crepis species), milk-vetch species (Astragalus whitneyi was most noticeable), paintbrush species (Castilleja chromosa and others), buckwheat (Eriogonum umbellatum) and phlox (Phlox stansburyi). Most of these can be easily seen within a half mile of the trailhead but the ~1+ walk to see the impressive stand of mule ears and arrow-leaved balsamroot (Balsamorhiza sagittata) is worth the walk!
I would assume that other places along the eastern slopes of the Sierra at similar elevations also have good blooms. I always recommend the South Fork of Big Pine Creek for early summer wildflower viewing.
Farther north, the Bodie Hills offers an alternative to the Sierra for wildflower viewing. Many of the areas that are dominated by low sagebrush are carpeted with yellow flowered buckwheats and white flowered phlox along with several other blooming species.
To see what is blooming in other areas of California visit the Theodore Payne Foundations Wildflower Hotline