Acacias are among the showiest blooming trees we can grow in the Bay Area. Fuzzy golden orbs and cylinders emerge suddenly on many species from winter into spring. Because these spectacular blooms often coincide with the shedding of airborne pollen by pines, oaks, and cypresses, people think they’re allergic to acacia, but usually it’s the conifers and oaks that are causing all that itchy sneezing.

A flowing 15-gallon-size Acacia boormanii was the first to go gold here in the nursery this January — and admiration seems to be trumping complaints about allergies. The profuse lemon-yellow flowers smother the lush mass of fine, grey-green phyllodes (leaflike structures common to many acacia species). This species is useful as a multi-stemmed screening tree, growing to about 15-feet tall but keeping foliage to ground level. It’s amenable to hard pruning nearly to the base every few years, or to training up into a cluster of sculpted trunks with clouds of foliage above. It will tolerate clay soils, and thrives in deep, well-drained soils. A little bit of summer water, especially inland, will keep it looking gorgeous.

Acacia boormanii, the Snowy River wattle, in January bloom

The intensity of acacia bloom in midwinter always comes as a jolt. The invasive Acacia dealbata, ubiquitous in suburban areas of the Bay Area and elsewhere in California, produces acid-yellow masses of flowers starting sometimes as early as December. (On the French Riviera it’s celebrated as “mimosa.”) You see similar flowers on the common San Francisco street tree, Acacia baileyana, offset by feathery, purple-grey leaves. The color grabs attention like a visual siren.

The hairy wattle (you wonder why we stick to botanical Latin?), Acacia vestita, is another of our favorites, planted at the front gate of the nursery.

Acacia vestita just beginning to bloom in mid-January 2010

By contrast with Acacia boormanii’s fluid, cloud-like form, Acacia vestita’s shape is unmistakable. Its weeping, ropy branchlets hang nearly to the ground, especially in youth. They bear silky blue-grey phyllodes in the shape of tiny, pointed, gibbous moons that contrast beautifully with the apple green skin of the branches and trunk. Growing quickly to 12 to 15 feet in height and width, it looks a bit like a green Mr. Snuffleupagus from Sesame Street. Okay–it’s a lot prettier than that, but there is a resemblance. Like most Australian acacias, it’s drought-tolerant and requires no fertilizer and will tolerate temperatures into the low 20s Fahrenheit.

Splashes of fragrant winter gold emerging now feel like that moment when a free dessert comes compliments of the chef. On top of a perfect meal, we didn’t expect or need it, but boy is it delicious.

We’re at the moment in San Francisco’s seasonal growing cycle when the relative quiet of the Thanksgiving-to-winter-solstice period breaks into smashing bloom with acid-yellow Acacia baileyana and Acacia dealbata, deep-sapphire early ceanothus, and delicate plum blossoms (annually finding their raison d’être).

We’re always looking for additions to these common midwinter elements and their glorious signs of mediterranean-climate flourishing. Down at the Presidio, in the casual median strip garden of Kennedy Avenue, Banksia praemorsa presents the most-stunning show in town right now. It’s a Western Australia native that loves sandy soil and even seaside conditions. Imagine banks of these 12-foot shrubs in Pacifica and Daly City and the outer Sunset and Richmond districts.

The evergreen foliage is quite pretty, too. It appears clipped by pinking shears, a form that inspires its species name, praemorsa. New growth emerges covered in bronze fur.

This Banksia's stems lean and rise upward.

This bush is in all stages of bloom, from bud to full glory, and the birds are loving it.

Not far from our store, in the Sunnyside neighborhood (near Glen Park), is an extraordinary grove of 100-plus-year-old palms surrounding a historic conservatory-like pavilion. It’s called the Sunnyside Conservatory, and, built in 1898 as a garden structure on a large country estate (before the city engulfed the area), it’s on San Francisco’s list of landmarks.

Most of the palms are Phoenix canariensis, the Canary Island date palm. Planted close together, their trunks lean gently away from each other in an unusual presentation for this species in our area. Most often we see them as very upright avenue trees.

Among these beautiful trees is a single spectacular specimen of the Chilean wine palm, Jubaea chilensis, with a huge, silvery, cigar-shaped trunk and an elegant crown of gray-green fronds. You can see its fat trunk on the left in the photo below. Jubaea is one of the two or three best-adapted palms for San Francisco and the Mediterranean climate zones of California — which is most of the heavily populated part of the state. Endangered in central Chile, its native habitat and a fellow-Mediterranean climate, it thrives in our summer drought, wet winter cold, and foggy coastal winds. It also produces tasty miniature-coconut-like nuts. Killing it for sugary sap to make wine is what eliminated the tree from vast areas of its habitat, although some in Chile have now devised a way to draw the sap without felling the palm, and the few remaining natural groves there are protected.

As rare as this spectacular species is, another landmark specimen grows not more than a mile away, on Yerba Buena Avenue near Monterey Boulevard. Was there a connection between their planting — maybe 19th century country neighbors shared rare plants? As part of the Sunnyside Conservatory’s renovation, a young Jubaea has also been planted in the garden. Because it is drought-tolerant and immune from the diseases that can attack the Canary Island date palm, planting young Chilean wine palms is a smart long-term investment.

The San Francisco Recreation and Park Department with the help of the Friends of Sunnyside Conservatory has been renovating the garden and structure over the past couple of years,  and the Friends are throwing a grand reopening party at 11am on December 5, 2009. What a great chance to enjoy a beautiful public palm garden!

Goodness, our strong tree opinions have landed on SF Curbed.

We’re in favor of any way to improve tree selection for San Francisco.

We had a conversation with our gardener friend, Mike, last weekend about deciduous trees — the beautiful, the useful, the disappointing, and the ugly. It’s autumn, and along our latitude (37 to 38 degrees north), many deciduous trees are starting to change into their stunningly colorful foliage before going dormant for winter. In San Francisco, not so much; our climate is too mild to allow most deciduous trees to put on the show they’re famous for in the Sierra Nevada, Japan, or the Appalachians, all of which share our latitude but not our climate. We have chilly summers and mostly frost-free winters here. Measured as the annual range of average temperatures, our climate’s mildness (but not warmth!) rivals that of Honolulu’s and San Diego’s. Our warmest month, September, isn’t very much warmer than our coldest month, January, and many deciduous trees need greater seasonal extremes.

Some deciduous tree species are lovely exceptions in SF, but for this post, let’s talk about gripes.

One species that’s a bugaboo for us is Pyrus calleryana, the Callery pear. It’s a classic indicator plant for our area, one that performs differently in different microclimates. In the right climate, which is much of the temperate zone of the United States, this species and its many selections, like ‘Bradford’, and ‘Chanticleer’, produce glorious fall color, burst into clouds of bloom in early spring, and grow to become respectable 40-foot trees. At the San Francisco Flower & Garden show last March, held at the San Mateo Event Center, we admired dozens of these trees in their silvery-white exuberance. We have seen the same healthy bloom every spring at a Marin County mall, the Town Center Corte Madera, where the pears also produce equally stunning orange foliage in fall.

Callery pear trees (Pyrus calleryana) in San Mateo, California

Both of these places are within 20 miles of downtown San Francisco, but Callery pears in the city perform poorly. Trees often hold their foliage while simultaneously pushing out insignificant blooms and popping premature leafbuds well into winter (and even spring), rarely coloring to any pleasing shade, rarely going fully dormant until February, if ever. When our neighbors around the Bay Area are thrilling to the March sight of pears in bloom, our SF trees are sputtering and won’t look okay until July. Perhaps 20 percent of SF’s Callery pears perform as hoped — except that even those 20 percent rarely approach the treelike dimensions of their suburban siblings. And, this last summer, we saw many damaged by fireblight. The irony of this post is that at no time of the year do they look better in San Francisco than now: Eventually through June and July they leaf out (even if they barely bloom) and get nice and glossy green.

It’s a testament to the low standards of wind-beleaguered San Francisco gardeners and landscape designers that few people recognize the poor performance of this tree. Drought, lack of heat, wind (plus poor soils!): Our climate is special, and that often means that trees grown for mass distribution, like Callery pears, are not actually suited to our mild winters and chilly, windy summers. It’s not because of where they’re grown (Oregon, or the Central Valley), but because of the tree’s preferences. But they’re available in quantity at a good price, reference books list them as hardy in our climate zone, and thus they get chosen for planting plans. Rumor has it that Callery pears have been chosen for the current reconstruction of Valencia Street between 15th and 19th streets. Sigh.

Our larger gripe is that we’re planting unhappy trees where beautiful, thriving trees could be grown. Unlike, say, the London plane tree, Platanus X hispanica, which (aside from the ‘Yarwood’ selection) trumpets its maladaptation with powdery mildew, rust and anthracnose weeks after leaves develop, Callery pear simply limps and mopes for six months of the year. In the second-densest city in the US, it’s an opportunity cost; mopey trees take the place of thriving trees, and depress the interest in planting more trees.

Perhaps the overarching gripe we have is inattention to place. Not paying attention to the performance of plants in specific microclimates leaves our city with uglier, unhealthier trees whose commonness cannot contribute to the character of this (climatically weird) place.

Another time, we’ll talk about deciduous trees that we love for San Francisco.

The New York Botanical Garden’s Plant Talk blog spotlights the “tree of life” — the coconut palm, Cocos nucifera.

The San Francisco Botanical Garden in Golden Gate Park is the home of two of the largest Andean wax palms (Ceroxylon quindiuense) growing outside of their South American home. They were planted as seedlings in the mid-1980s. The SFBG Society’s current newsletter goes into detail about this species, uniquely suited to our coastal California climate. They uncover the fact that Colombia chose in 1985 to protect this species, their national tree, in a cloud forest wildlife preserve, Valle de Cocora, where other rare and endangered species, like the Yellow-eared Parrot, also live. Andean cloud forests are the origin of many of Californians’ favorite ornamental plants, like angel’s trumpets (Brugmansia species) and fuchsias. We think this palm would look beautiful as an allée or a grove in a park. In habitat it becomes the tallest of all palms, at nearly 200 feet. Its cousins within the genus Ceroxylon vary in size, and some smaller species are exquisite palms for home gardens in the San Francisco Bay Area and coastal California. We carry a limited supply of five-gallon youngsters here at Flora Grubb Gardens.

Two Andean wax palms (Ceroxylon quindiuense) growing at the San Francisco Botanical Garden in Golden Gate Park

We’re loving the attention paid by Burrito Justice, a Mission District blog, to neighborhood trees — including palms, of course.

One of the palms that we can grow better here in coastal California than almost anywhere else is Rhopalostylis sapida, the Nikau of New Zealand. (It’s also known as the shavingbrush palm.) It thrives in our cool, foggy climate, even tolerating the incessant summer wind of San Francisco. Here are some young trees at the San Francisco Botanical Garden in Golden Gate Park:

Rhopalostylis sapida at San Francisco Botanical Garden (Strybing Arboretum)

We found an awesome gallery on the New Zealand Palm Society’s website with lavish photos of this beautiful species in its homeland, Aotearoa (the Maori name for New Zealand).

This species grows farther from the Equator than any other palm, at 44 degrees south latitude in the Chatham Islands, 500 miles east of New Zealand’s South Island. That latitude in the northern hemisphere runs by Portland, Maine,  Toronto, Canada, Genoa, Italy, and Eugene, Oregon. Here on the California coast, specimens have succeeded at least as far north as the Mendocino Coast Botanical Gardens. There are reports of specimens surviving farther north, on the southern Oregon coast; Brookings’s microclimate, Sunset zone 17, would be a good one in which to experiment with Nikau palms.

Nikaus like some shade when young, but once they form a trunk, they thrive in full sun in the fog belt. Even moisture and mild fertilizing will keep them growing steadily; they are not drought-tolerant and won’t endure freezing below about 25 Fahrenheit (-3.9 celsius). Inland, where ocean fog rarely penetrates, dry heat and winter frost limit their usefulness, but they are worth planting in Sunset zones 17, 16, and those parts of zone 15 with protective evergreen tree canopy. They are reputed to tolerate clay soils better than most palms.

One very nice Nikau here in San Francisco is at Project Artaud, an artists’ community located in the northeast Mission/Potrero Hill neighborhood between Florida and Alabama and Mariposa and 17th streets. Our friend Benjy Young has planted many rare and beautiful palms there over the years, many of which are visible from the street. We will focus on some of their other species in future posts.

Nikau palm with red fruit at Project Artaud, San Francisco