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Fremontodendron californica, Flannelbush Fremontia: a spectacular late=spring and summer bloomer

April 14, 2008
Julie Monson

 

While Fremontodendron californica is its proper botanic name, this plant is also known as flannelbush and is still referred to as fremontia, the name given to the quarterly journal of the California Native Plant Society. Choose which you like. My choice is fremontia, the name used in California Native Plants for the Garden (Bornstein, Fross, O’Brien, 2005). Incidentally, this plant is named for John C. Fremont, a celebrated 19th century California explorer, politician, and entrepreneur.

 

Fremontia, one of the more spectacular California natives, grows quickly to a tall, slender shrub covered with 3-inch yellow blossoms in late spring through early summer. Evergreen, it is a show-stopper when in bloom, and a useful background shrub the rest of the year. About 5 years ago, we planted three Fremontodendron californica in a sunny garden area planted mostly with natives, and were astonished to see them grow to 10 -12 feet within 3 years, filling the center of our mound with foliage and yellow spring blossoms. Suddenly, after a wet spring, two died. That is when I learned that fremontia cannot tolerate damp soil and requires dry soil during the summer. In Marin County, fremontia will likely thrive without any irrigation. After we disconnected summer irrigation, our remaining fremontia flourished nicely. My reading, observations and experience indicate that this colorful shrub can be very useful in some garden settings, especially if the gardener knows its benefits and limitations.
Fremontia is something of a relic among California’s native species. It is a survivor from a period 60 million years ago when California was less mountainous and more tropical. Two other survivors from this same period include fan palms and ironwood trees, still found in desert climates.   Although its natural habitat is on rocky slopes of open chaparral or woodland between 1200 and 6500 feet of the coast ranges and Sierra Nevada, fremontia does well in sunny, dry gardens in Marin.
Fast growing but typically short lived, fremontia seldom reaches its potential of 30 feet with 20 foot spread.   It can be pruned successfully to keep it in scale with urban gardens. It is ideal when planted with other drought resistant California natives, particularly understory species like prostrate forms of ceanothus, coffee berry, or western sword ferns. In a newer garden, where slow-growing natives take years to fill in, a few fremontia provide quick results (spectacular when blooming) and can be pruned, replaced or even removed later when other shrubs and trees have matured.
Several successful cultivars of fremontia are available and these promise even greater rewards to the gardener. ‘California Glory’ is one of the best and has bright yellow flowers, three-lobed dark green leaves, with initial upright growth, tending to arch with age to 20 feet.   ‘El Dorado Gold,’ another hybrid, is lower growing from 4 to 6 feet, spreading to form a mound up to 12 feet, ideal as a sunny, drought tolerant ground cover. Other successful cultivars include ‘Pacific Sunset’ and ‘San Gabriel,’ both tall, and ‘Ken Taylor,’ which has showy, large orange-yellow blossoms, effective when used on a slope or retaining wall.
Fremontia has spreading, shallow roots so it’s advisable to stake young plants. Because it is susceptible to root rot, Judith Lowry recommends planting it on mounds or slopes mulched with as much as 8 inches of mulch. Good drainage and loose soil are critical. While it might survive damp, clay soils for a while, it’s not a good choice in these conditions.
Leaves and the small, bristly seed capsules of fremontia are covered with tiny, skin-irritating brownish stellate hairs. After pruning fremontia, or working near it, the gardener is advised to shower and wash clothing. For this reason, one should not plant it adjacent to a patio or well-trod walkway. To my mind, this primary disadvantage is overcome by the plants many advantages, another of which is that deer leave it alone, perhaps because of its irritating “fuzz.”

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