Yosemite National Park has just published the following wildflower report:
With a few sunny days in late May, the Yosemite region’s spring flower bouquet has increased its blooms. The Merced River Canyon remains alive with whites, yellows, and pinks—especially the purplish-pink of farewell-to-spring (Clarkia dudleyana) growing in masses on the canyon’s grassy slopes. Identify it by its wedge-shaped petals, often with purplish dots and streaks of white. Although cold weather delayed the Yosemite Valley flower show, it has started with a white theme between the mountain dogwood (Cornus nuttallii) and buck brush (Ceanothus cuneatus) blossoms.
Traveling from Mariposa to El Portal along Highway 140 provides a good number of the late spring flowers, including flowering shrubs. The yerba santa shrub (Eriodictyon californicum), with its leathery leaves, begins to display its lavender flowers crowded in scorpioid cymes. Culturally, yerba santa has highly aromatic leaves used as a decongestant or dried either to smoke or chew as tobacco. The evergreen shrub chamise (Adenostoma fasciculatum) displays small white flowers, against its resinous foliage, on dry slopes and rocky soils in the oak-woodland zone. Enjoy this short window of chamise’s sea of foamy white before flowers turn a rather drab brown for the rest of the summer season. Also, the California buckeye (Aesculus californica) has started to show its picturesque inflorescence in an elongated stance. By mid-summer, the buckeye tree will bear smooth leathery capsules that are pear-shaped and go dormant to survive the California heat.
Still noticeable along the Highway 140 roadside is the bright yellow common madia (Madia elegans)—which flowers in the spring and into the summer. It has yellow disk florets plus eight to 16 ray florets, which can be colored a solid yellow or have a maroon blotch at the base. New along Highway 140 is purple milkweed (Asclepias cordifolia), an important host plant for caterpillars. Distinguish purple milkweed from hairy-leaved milkweed varieties by its smooth purplish leaves that give the entire plant a purplish hue. Other flora along this route are mountain jewelflower (Streptanthus tortuosus), Chinese houses (Collinsia heterophylla), blazing star (Mentzelia crocea), twining brodiaea (Dichelostemma volubile), and Western wallflower (Erysimum capitatum). Also, look also for the yellow heads of golden yarrow (Eriophyllum confertiflorum), which is not a true yarrow but is in the woolly sunflower genus, and the orangey-red splash of Applegate’s paintbrush (Castilleja applegatei).
The fleshy leaves of brightly colored stonecrop rise of out steep rock crevices often dark with dew. Sierra stonecrop (Sedum obtusatum) is the most common stonecrop in Yosemite—first described from specimens collected near Vernal Fall by Henry Bolander in 1866. Its thick green leaves form a rosette base with erect reddish stems that are topped by star-shaped yellow flowers. Also in the stonecrop family is the related liveforever (Dudleya cymosa ssp. cymosa) with its fleshy-leaved rosettes, red stems and flowers that vary from bright yellow to orange or red.
Continuing to stand tall are two thistles on the Sierra landscape. These are Anderson’s (Cirsium andersonii) and California (Cirsium occidentale) thistles. Yosemite has a third native thistle: alpine thistle (Cirsium scariosum), but you’ll have to wait until mid-summer to find alpine thistles growing at high elevations—still covered right now by snow. What’s a good way to tell the difference between a native and a non-native thistle? No thistles native to Yosemite have wings or ridges on the stems. Beware that the pink Anderson’s thistle and California thistle look like, and can be easily confused with, the invasive bull thistle (Cirsium vulgare).In Yosemite Valley: Besides noticing the mountain dogwood in Curry Village, Yosemite View Lodge and around the pond in front of The Ahwahnee, look for a moderately showy ceanothus shrub called deer brush (Ceanothus integerrimus) , distinguished by its elongated flower panicles and opposite leaves. Deer brush can be seen at 2,000 feet is most prominent at about 4,000-foot elevation in the submontane chaparral. Also, during the start of the flower season in the Valley, splashes of red at ground level definitely catch a wildflower observer’s eye. An intense red, the snow plant (Sarcodes sanguinea) lacks the green pigment chlorophyll required to synthesize sugars in sunlight, instead this parasitic plant feeds on soil fungi.
Monkeyflowers throughout Park: While on a May weekend monkeyflower study, botanists were reminded of the dozens of monkeyflower species that live here. About 100 species exist in western North America with 63 species known in California and close to half of these occurring in Yosemite. Park staff always keep an eye out for rare species. Found were the special status yellow-lip pansy monkeyflower (Mimulus pulchellus) and the slender-stemmed monkeyflower (Mimulus filicaulis). The pansy monkeyflower grows between 2,000 and 6,500 feet in elevation, and the slender-stemmed monkeyflower grows between 3,000 and 5,700 feet.
Non-Native Species: What else might you see on the Sierra wildflower landscape? It’s possible to find several plants that just don’t belong—in other words they are non-natives. Reddish tufted vetch (Vicia benghalensis), for example, is a showy purple that claims attention. Like many non-natives, this invasive plant establishes itself around inhabited areas, such as like roadsides and developed areas on hillsides in the El Portal area.As early summer approaches, visit the Big Meadow area in Foresta for the post-fire blooms. There, you’ll typically see star-tulip, which are white lilies that sit low to the ground, as well as common madia, Gray’s lupine, and fan violet. Access the Big Meadow area from Foresta Road near the El Portal park administrative complex—but plan a LONG walk because this gravel road is not suggested for driving. Or, access the other end of Foresta Road and the Old Coulterville Road from the community of Foresta, which is off the Big Oak Flat Road (Highway 120) inside the park.
Consider a hike along the Hite Cove trail, located on the Sierra National Forest along Highway 140 seven miles before the Yosemite National Park entrance. Find the Hite Cove trailhead behind the old Savage’s Trading Post location, where a historic sign still marks the site now known for its typical dense carpet of spring flowers. The 4.5-mile trail (one way) follows the south fork of the Merced River.A safety warning no matter where you are in the park: March brought the Yosemite area heavy snow that broke tree tops and limbs at unusually low elevations. Beware of damaged trees above you that could fail any time.
To follow Yosemite wildflower bloom go to the park’s Now in Bloom page
Natural History Wanderings 
I wish I had seen all of that a week ago, when spending a few (sunny, perfect) days
touring Hetch Hetchy, 140 from Yosemite to El Portal, and Yosemite Valley.
The dogwoods are great, the redbuds going lower to El Portal were in “full seed,” but
another star I want to add is the black (Kellogg’s ) oak now, with its new pink leaves.
Also Meadow Rue on the way to the falls at Hetch Hetchy, and lots of Harlequin Lupine on 120 on the way up. No snow plant yet a week ago, but lots of snow at Crane Flat–
Plus Yosemite !
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By: Judy Keene on May 27, 2011
at 7:25 PM
Judy,
Thanks for your comments and additions.
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By: Sandy Steinman on May 28, 2011
at 8:30 AM