Early Spring Wildflowers of Mount Diablo
by Kevin Hintsa
The winter rains and increasing daylight of early spring triggers a spring bloom for many of Mount Diablo's native wildflowers. The exact timing and quantity of blooming wildflowers will vary greatly year to year as it is controlled by a number of environmental factors. By late February there are a number of flowers to view, especially in the chaparral and at low elevation grassy hilltops. The following include most of the more striking species that one might find in the first three months of the calendar year.
Bear Brush (Ganya fremontii) starts off the new year in a bizarre manner by blooming in early January at the summit of Mount Diablo. This uncommon evergreen shrub, resembling the evergreen oaks in both leave and flowers, produces two inch long pale lavender catkins on the male shrubs. Blooming may be triggered by the increasing daylight as it often blooms in icy conditions. The more common Coast Silk-tassel (Garrya elliptical is easily found between Curry Point and Sycamore Canyon in February and March).
Manzanita (Arctostaphylos sp.) is perhaps the star attraction of December to March. These evergreen shrubs with red bark fill the chaparral (and a few wooded slopes) with delicate white to pink tiny bell-like flowers that attract a great number of insects and the occasional hummingbird. The Mount Diablo Manzanita (Arctostaphylos auriculata) grows only around Mount Diablo and has the pinkest blossoms of the mountain's manzanita. It is easily seen around Wall Ridge, Live Oak Campground and also between Curry and Knobcone Point.
Another early bloomer is Chaparral Currant (Ribes malvaceum). This deciduous shrub often begins blooming in late December at lower elevations, finishing at the summit around early May. The flowers are pink and are quite striking when seen in mass. It is easily seen around Knobcone Point and along Summit Road. The similar Gooseberry differs in having thorns and smaller flowers. Mitchell Canyon and the summit area are good places to look for it.
Indian Warrior is a semi-parasitic herbaceous plant of chaparral-pine areas. The red green leaves are a pleasant sight in early March along Wall Ridge or Curry to Knobcone Point. It blooms in April at the summit. The newly opened leaves are pure red in this and many other species as a protection against ultra-violet light.
Members of the Mustard family are well known early bloomers. Milk Maids (Cardamine californica) is very common just about everywhere on Mount Diablo, often occurring in heavily shaded forests. Its simple white flowers can be common by mid-February at low elevations, finishing at the Fire Interpretive Trail in May.
Our state flower, the California Poppy blooms nearly year round, mostly March to October on Mount Diablo. Its lacy gray-green leaves and golden yellow to orange flowers are well known to most Californians. It is generally found in the grasslands below 3500 feet. Check North Gate Road in mid-April to early May for peak mass bloom.
Buck Brush (Ceanothus cuneatus) is an evergreen shrub that is fire dependent, as it gets crowded out in older stands of chaparral. Its mass of white blossoms (smelling like popcorn) starts in early February along lower South Gate Road, finishing in May at the Fire Interpretive Trail. Jim Brush (Ceanothus oliganthus) is another of the so-called California Lilacsi. It has powder blue blossoms and blooms from late March through May, more commonly on the north side of the mountain.
Very pleasing to the eye in early March is Johnny-Jump-Up (Viola-pedunculata). These are golden yellow with black markings and have a striking reddish brown underside. Look for it a Curry Point. Much smaller and more widespread on the mountain is the similar looking Mountain Voilet (Viola purpurea), blooming March to May. It is fairly common in the area around the Summit.
Brewer's Rock Cress (Arabis Breweri) is found on rock outcrops at 1200 feet to the summit. Its small pale green leaves grow in rock crevices and it has beautiful pink to purple flowers (that later form curved seed pods). The summit area is the best site to study this species, but also look for it at the Falls Trail in Donner Canyon.
Mosquito-bills (Dodecatheon hendersonii) is the common species of Shooting Star around Mount Diablo. The nodding pink flowers are quite adorable, especially when in mass. The leaves are simple and basal. Look for it from mid February through April, especially in Mitchell Canyon where it is very common.
Grand Hound's-Tongue is a widespread member of the forget-me-not family on Mount Diablo, most found in wooded areas of light shade. It has foot tall flower stalks with powder blue to violet flowers. It usually is well in bloom by March 1 at lower elevations, and finishes in late April along the Fire Interpretive Trail.
Mount Diablo Manzanita, Arctostaphylos auriculata
Brewer's Rock Cress, Arabis Brewer