The Dry Garden: Stunning flannel bush comes with prickly problems

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Some years ago, the website of Native Sons Nursery had a photograph of a California flannel bush that had been trained to grow along a garden wall. Each bloom in a spangle of flowers was the size of a teacup. Their yellow could outshine a daffodil, or sunflower. This wasn’t a garden, it was a garden that Matisse dreamed. On seeing that photo, so began years of looking in Los Angeles area gardens for espaliered examples of the glorious genus of natives whose botanical name is Fremontodendron.

And never finding one.

It turns out that the photograph, above, was taken in Guernsey by Native Sons co-founder David Fross, who had just left a place that serves alcohol when he saw the glorious display by one of the signature plants of California chaparral growing in one of the Channel Islands between Britain and France. “I’d had two martinis and half a bottle of wine, came around the corner and late evening light was crashing into this yellow door. At first I was staring at the door. Then I focused and said, that’s Fremontodendron.” It ran almost 50 feet along a wall.

As he kept looking, he found that yet more artfully espaliered displays of the plant named for the western pathfinder John C. Fremont were almost invariably in Britain, such as that in his photo at right, taken in London in 1997, or France, or on an island between the two places. The reasons are many, the first being that the British and British adjacent are better gardeners. The second is that the cooler climate has a refining effect on these strapping western plants.

“In England, a Fremontodendron might put on four inches of new growth a year,” explained Bart O’Brien, special projects director of Rancho Santa Ana Botanic Garden in Claremont. “In our area, they can put on six to eight feet in three months in the spring.”

Those, like me, intent on pinning a flannel bush against a wall in its home territory should be warned that Fremontodendrons come armored. While a USDA Forest Service information sheet identifies the leaves as edible by ruminants, they are highly irritating to humans. Under the microscope, tiny hairs look like medieval maces, said O’Brien. “Think of them as having projecting spines in every direction. If you’re doing any maintenance or raking up dead flowers or leaves, do that last and go take a shower and put those clothes into the laundry as soon as possible.” San Marcos Growers advises wearing goggles. Fross said he asks his crews to wear masks when they load the plants on delivery trucks.

Another challenge to using this native in Southern California gardens is soil. Fremontodendrons do best in the free-flowing sandy alluvium of the foothills. “In the wild, they often grow on slopes,” said O’Brien. “Rain comes in and flows out.” By summer, the evergreen plants are dormant, in which state summer irrigation swiftly kills them. Death happens faster in clay.

They not only drown, they smother. Mulch should go nowhere near the root crown, where they are highly susceptible to rot. Foothill arborist Rebecca Latta said the soil line should sit just where the top roots meet the main stem.

Although now is the time to admire their flower, the best time to plant a Fremontodendron is late autumn. “Generally speaking, we plant them in the fall, water them in, and then we’ll only water them the same year they’re planted if they need it and hardly ever again,” said O’Brien. “Most that make it through that first summer are perfectly fine forever after.”

Breeding our native flannel bush with the South American Fremontodendron mexicanum to produce plants better adapted to life near sprinklers, drip lines and hoses has led to hybrids such as California Glory, Pacific Sunset and San Gabriel. All are slightly more tolerant of water than F. californicum, said O’Brien, but not much.

However a much more water-tolerant hybrid is in the works. This cross, between Fremontodendron californicum and the tropical Monkey’s Hand Tree (or Chiranthodendron pentadactylon) is being propagated for eventual release into the trade at Rancho Santa Ana.

First accomplished a quarter-century ago by (then) Rancho graduate student Austin Griffiths, the hybrid produced a stunning improvement. While Fremontodendron californicum’s nectar value is minimal, the cross has sunward-raised flowers that fill up with rain, attracting not only hummers but all manner of birds to drink. Curious, Fross once tasted water from the blossom. “It tasted like nectar of the gods.”

Smaller Fremontodendron selections recommended by Fross and O’Brien include Ken Taylor and El Dorado Gold. Fross likes Butano Ridge for its striking red stems.

All Fremontodendrons have long, stunning flowering periods. How early they start and late they last depends on location and weather. Foothill specimens are flowering now, and coastal ones should be following. “Cool weather makes them last a lot longer,” said O’Brien.

Though he and Fross are old friends and with Santa Barbara horticulturist Carol Bornstein are coauthors of “California Native Plants for the Garden,” O’Brien doesn’t think this native can be given its most stunning treatment on home ground. If it grows at all in our gardens, it grows too fast to be espaliered. Then there are those irritating leaves.

However, having wandered tipsily around that corner in Guernsey and being stunned by what he saw, years later and stone-cold sober, Fross still believes we can trim and pin the plant to artful effect here, at least in cooler coastal areas.

Watch that space.

-- Emily Green

The first and fourth photos show a Rancho Santa Ana Botanic Garden cross between the California flannel bush (Fremontodendron californicum) and the tropical monkey’s hand tree (Chiranthodendron pentadactylon). The bottom two photos show a newly planted garden Fremontodendron ‘San Gabriel,’ a hybrid of F. californicum and F. mexicanum introduced by Rancho Santa Ana Botanic Garden.

Photos of flowers by Emily Green