Human Flower Project

Orrington, MAINE USA

flag flower bed

parker basket thumb
Princeton, MAINE USA

Thursday, April 10, 2008

Street Trees: Let’s Think Outside the Wires

Local Ecology’s Georgia Silvera Seamans explains why, in choosing a city’s trees, there’s a lot more to consider than power lines.


Hawthorn tree in bloom: short, showy, and nectar rich

So why isn’t it a choice of Oakland’s city foresters?

Photo: Georgia Silvera Seamans

In urban settings, human tensions arise over the selection of large stature or small stature street trees.  The “Right Tree in the Right Place” planting policy recommends that short stature trees – 25 feet or less – should be planted beneath utility lines because the canopies of these trees do not interfere with overhead wires.  But emphasis on height alone neglects larger issues—of ecosystem value. 

Large stature trees—like red oak, London plane tree, or sweetgum—do interfere with overhead wires, but they also provide greater ecosystem benefits than do small stature trees: they sequester (store) more carbon, filter more particulate matter from the air, and intercept more rainfall via leaves, trunk, and soil (and slow runoff into storm drains). And, because of their larger crown spread and evapotranspiration capacity, larger trees cool larger areas of surrounding air (cooling nearby infrastructure and buildings, too).

In a study of Berkeley’s street tree canopy conducted by the USDA Forest Service Center for Urban Forest Research (CUFR), researchers found that city trees saved $12.58 per tree in annual electricity costs. As for capturing stormwater runoff, the average street tree intercepted 1,478 gallons, a value of $5.91 per tree annually. The researchers also found that, overall, larger stature trees provided the most benefits: the average small, medium, and large deciduous street tree produced annual benefits totaling $32, $79, and $96, respectively. (Note: Author Georgia Silvera Seamans, assisted by Qingfu Xiao, research scientist at UC Davis, obtained this information as part of a research grant with Urban Releaf.)


Ginkgo (Ginkgo biloba): as with many large trees, its flowers aren’t showy

Photo: Georgia Silvera Seamans

Though not all short stature trees have showy floral displays, they tend to have larger, more conspicuous flowers. Most people think of herbaceous perennials as the plants that attract bees and butterflies, but flowering trees are definitely popular with wildlife too. As cities make tree selections, they should consider the “wildlife-value” of species that produce fruits, seeds, nuts, catkins, and acorns.  A tree’s wildlife-value in the larger ecosystem, something not usually quantified, involves its floral services for small, highly mobile species like butterflies and bees and some birds.  Hummingbirds, for example, utilize showy flowers for nectar.  As well, floral displays attract insects on which non-nectar eating birds rely.  Not only are the showy flowers of shorter stature trees attractive to birds and bees, their exuberant flowering draws “oohs” and “aahs” from us humans.  I have never visited Washington, D.C., in the spring, but I have heard the buzz about the mass blossoming of the Mall’s 3,000 cherries.  (At this year’s San Francisco Flower & Garden Show, the USDA Forest Service created an urban forest garden.  The sign below the coast live oak, interestingly enough, listed the aesthetic monetary value of the oak over 40 years as $5,210.) 

Given the dual appeal of short stature trees, I was curious to see which varieties municipal urban forestry departments selected.  A natural choice for a case was the City of Oakland.  I am an intern of urban forestry issues for the City of Oakland Mayor’s Office.  Oakland’s street trees are managed by its public works agency.  The city’s Official Tree Species List, as of November 2007, has a limited palette of small stature trees.  The list contains seven species: Strawberry tree (Arbutus unedo), Eastern redbud (Cercis canadensis), Crape myrtle (Lagerstroemia indica), Photinia (Photinia fraseri), purple leaf plum (Prunus cerasifera ‘Thundercloud’), Evergreen pear (Pyrus kawakamii), African sumac (Rhus lancea), and Water gum (Tristania laurina ‘Elegant’).  Many of Oakland’s residential streets are lined with overhead utility wires, so I expected a longer list of short stature trees.

Of these seven species on Oakland’s approved street tree species list, four have documented wildlife value.  According to the USDA Forest Service Silvics Manual of North America (1990), the eastern redbud nectar is used for honey production (and the fruit is eaten by cardinals, bobwhites, ring-necked pheasants, rose-breasted grosbeaks, white-tailed deer, and gray squirrels).  The crape myrtle attracts “beneficial insects” according to the UC Davis Arboretum plant database, but it does not give a list of insect species.  Water gum or Tristania laurina provides nectar to honey bees; these bees are common to very common visitors of the water gum flowers.  The UC Berkeley Urban Bee Garden project also observes that water gum flowers occasionally attracts small, native bees.


A powerline-centric view of urban tree selection

Image: Pacific Gas & Electric

As mentioned previously the primary limiting factors in planting the right tree in the right place with regards to overhead utility lines is height; trees should be twenty five feet or less in height at maturity.  Of the seven species listed by the City of Oakland as “small,” two can attain thirty feet in height: the crape myrtle and the purple leaf plum.  Two of the species categorized as “medium” are listed with heights of twenty feet: the bronze loquat (Eriobotrya deflexa) and the Saint Mary magnolia (Magnolia grandiflora ‘Saint Mary’).  In general, magnolias are medium-sized trees, but I gather that the Saint Mary variety is typically twenty feet at maturity.  The flower of the loquat attracts bees (and birds eat the summer fruit). 

The City of Oakland does not list the hawthorn.  I have noticed bees buzzing around and landing on hawthorn (Crataegus species) flowers in my Berkeley neighborhood.  My casual observation is supported by the UC Berkeley Bee Garden project.  Crataegus laevigata attracts five to nine honey bees every three minutes for pollen and nectar, while C. phaenopyrum (Washington hawthorn) attracts five to nine honey bees every three minutes and occasionally attracts small and medium bees for nectar.

Of course, wildlife value is not limited to short stature, showy, flowering trees, and flowers are not the only source of value.  Linden trees (Tilia species) attract bees in great numbers according to observations made by the Cornell University Arboretum.  The valley oak (Quercus lobata), according to the UC Davis Arboretum plant database, attracts butterflies, beneficial insects, and birds.  But, the valley oak does not make a good street tree.  Urban sidewalks are not designed to accommodate this large, broad-crowned California native that requires “deep soils where it can tap groundwater.” 


A coast live oak in its namesake city, Oakland, California

Photo: Georgia Silvera Seamans, Local Ecology

Actually, the City of Oakland is named for the oaks that used to cover its land area.  The coast live oak (Quercus agrifolia) is conspicuously absent from the city’s list of large tree species.  This species would require a large growing area and the majority of residential sidewalks in Oakland are six feet wide; a four-foot right of way is required by the Americans with Disabilities Act.  To see an urban mature coast live oak (and its optimal growing space), visit Oakland’s City Hall Plaza.

Posted by Julie on 04/10 at 11:22 AM
EcologyGardening & LandscapeSciencePermalink

Tuesday, April 08, 2008

Garden Bloggers Cross-Pollinate

A weekend in Austin, Texas, pitches three dozen garden writers together: let the hybridizing begin!


Writers ooh, ahh, click over the ‘Embroidery Garden’

at James David and Gary Peese’s home in Austin

Photo: Human Flower Project

Writing is solitary, whether it goes on in an ivory tower or a partitionless newsroom with a hundred jangling phones. So the Garden Bloggers Spring Fling that took place in Austin over the weekend felt strange and delightful – like an orgy.

There were 38 of us, thereabouts, gathered in the sunshine without so much as a paragraph to stretch over our private identities. Bloggers from Illinois, Louisiana, Maryland, Wisconsin, Tennessee, Idaho, New York, Indiana, Oklahoma, Georgia, and all over Texas (yes, even North AND South Austin) spent a humming two days together. We visited a public garden for $8, and several private ones for free. We hung out at a local nursery, listened to an inspiring talk over fajita lunch, let our hair down at organizer Pam Penick’s house and garden, and gorged on a family-style barbecue dinner.


Carol of May Dreams Garden discusses garden blogging at Pam Penick’s house during the Garden Bloggers Spring Fling, April 5, 2008

Photo: Human Flower Project

After all that we’re not exactly “family,” but we surely cross-pollinated in ways that only our subsequent writing, thinking and photography will bear out.

There are already loads of interesting accounts of the event on the web, with a compilation to come on Pam’s site, Digging. Here’s some pollen we picked up, from bloggers and others throughout the weekend, delivered orgy-style:

There is such a thing as too-good drainage: Frances, who gardens on a slope in East Tennessee, swears that’s so.

People aren’t making money off their gardening weblogs – or if they are, they were mighty quiet about it.

The term “live oak” is fiercely contested; we witnessed a spirited discussion between a transplanted Texan and a transplanted Georgian, both natives of England and so, by birthright, experts in such matters.

Wordpress seems the blogging software of choice, though there were lots of grumblings about it. Kathy Purdy, who has her own blogging advice site, gave a tutorial on Pam’s porch and brought along the telltale Wordpress for Dummies.

imageSnow Melt, iris hybridized by M. Sutton at the Natural Gardener

Photo: Human Flower Project

Bearded iris really can grow in Austin. Really. We met a volunteer from the local iris society who was weeding a bed of 800+ varieties at the Natural Gardener. And the American Iris Society will actually hold its national meeting here in a week.

Several of the most enchanting garden writers we met are also historians, deep in to genealogy and regional research. We especially hope that Mary Ann Newcomer follows through on her study of Polly Bemis, a Chinese-American pioneer whose Idaho garden grows on.

imageFrom poolside, gardens of James David and Gary Peese in West Austin

Photo: Human Flower Project

REVOLUTIONARY PARADIGM SHIFT: Better listeners told us that James David and Gary Peese, whose imperial gardens we visited Saturday afternoon, are not so sweet on spring. Their favorite season is late summer/early fall. Let’s say that again, another way: Their gardening year revolves around the Texas summer because it’s the one reliable season here. As in, 112 degrees. As in, hasn’t rained for four months. This is samurai gardening!! Rather than dreading, moaning, and if possible running like hell from the facts of August, they face up, figure out, and work to make that time splendid. Honestly, just the idea sounds impossible—even nauseating—to us, but the thought has been planted. And our “endure” or “cut and run” approach hasn’t even been character building.

The way to pronounce “clematis” is klem-e-tis. One of the aforementioned English experts confirmed this—as gratifying an episode as we could imagine (since that’s how we’ve always said it).


Lucinda Hutson’s purple house and wonder garden, Austin

Photo: Human Flower Project

The Virgin of Guadalupe smiles on gardens, as proven by Lucinda Hutson. Her serendipitous invitation was the icing on the orgy Sunday morning. About a dozen of us wandered around waist high snapdragons, chard and poppies, sniffing leaves from her allspice tree as images of Our Lady—in stone, paint, tile, wood and beadwork—blessed our every step.

That plant we have tried unsuccessfully to kill for nine years is actually a treasured “native” – Twisted leaf yucca (Yucca rupicola) – on display at the Lady Bird Johnson Wildflower Center. Terrific – antipathy has turned to pride, and there’s one less thing on our garden hit list.

“Tell me, what is it you plan to do

with your one wild and precious life?”

The famous last line of Mary Oliver’s poem now has a context, thanks to Tom Spencer.

imageFearless leader and ace-pollinator, Pam Penick

Photo: Human Flower Project

And despite the bluster, everything is NOT bigger in Texas. One out-of-stater looking over a patch of bluebonnets Saturday morning quietly confessed: “I thought they would be much taller.”

To Pam Penick, the prime pollinator of this whole event, thank you. We’re also grateful to organizers MSS (Zanthan Gardens), Diana (Sharing Nature’s Garden) and Bonnie (Kiss of Sun) for all the behind the scenes work. You all make orgy-hosting tasteful and heavy lifting look easy. 

Posted by Julie on 04/08 at 02:51 PM
Art & MediaCulture & SocietyGardening & LandscapeTravelPermalink

Sunday, April 06, 2008

Gardenias on the Left—Lady Day

With vocal improvisations to beat the band—and white flowers behind her ear—Eleanora Fagan became Billie Holiday.


Billie Holiday with her dog “Mister,” 1946

Photo: William Gottlieb, via Library of Congress

Athena had her helmet and Spanky McFarland his two-tone beanie. Where would The Cat in the Hat be today except for that teetering stovepipe with the stripes? Curled in obscurity.  Headgear makes for legend. Ask Monica Lewinsky.

Flowers have been accessories to myth, too. We’re thinking of Billie Holiday, born April 7, 1915. Do you even know what she looked like? Maybe not, but you know that grainy,  supple voice and recognize her beautiful attribute: the white flower she wore next to her face. Like most flower emblems, it richly suggests – sensuality, glamour, fragility – without ever pinning much down. Pins are for taxonomy, not myth.

In anticipation of “Lady’s Day’s” birthday, we hunted for the story behind her floral signature and found several. The most convincing, in its specificity and chronology, is biographer Bud Kliment’s account of the early 1940s:

“Holiday’s success at the 52nd Street clubs (New York City) was partly due to her becoming a torch singer. Many people identified with her songs about loneliness and lost love, especially at a time when the horrors of World War II were affecting everyone’s life. ‘In some ways,’ noted (historian Arnold) Shaw, ‘Billie’s tortured style, the sense of hurt and longing, may have been a perfect expression of what servicemen and their loved ones were feeling.’

imageBillie Holiday with fresh gardenia

Photo: via Maryland Civil Rights

“During Holiday’s tenure at Kelly’s Stable, Sylvia Sims, a fellow jazz singer, furnished Holiday with an accessory that was to become a lasting part of her image. One night before a performance, Holiday burned her hair with a curling iron. Sims, who was in the room with her, promptly went to a club down the street, where the coat check girls were selling flowers. Sims bought a big white gardenia and gave it to Holiday, who wore it that night to cover the burned section of her hair. She liked wearing the flower so much that she began to put a gardenia in her hair before every performance.”

As human-flowers so often manage to be, Billie’s gardenia was at once an attraction and a distraction. A come on and a cover up. “Look at me,” it says,  “but don’t look at me.”

Could this picture, taken when she was only two, also have inspired her to adopt the white flower as a personal accessory?

Holiday usually chose gardenias but not always (Here’s quite an amazing orchid). Sometimes the blossoms were real, though she wore fabric flowers, too—either up front,  above her brow, or most often cascading along the left side of her face. After the hair-burning episode (gardenia of expediency), was this a kind of code? We believe that among Polynesian cultures, a woman’s wearing a flower over her left ear means something quite different from a bloom on the right. But does a lefty flower say ”Let me take you down” or “I’m taken, buzz off”? Interpretations we’ve found devolve into a hilarious snarl. In any case, Billie Holiday’s audiences were not Polynesians. They were jazz buffs and curiosity seekers, or just lonely people looking for great music that sexuality and exoticism could enhance.

Certainly, Billie’s gardenias were only one element of her mythology. Her singing was the soul of it, and stories of rape and prostitution, her heroin habit and incarceration, though perhaps not so news-worthy these days, shocked her contemporaries and underscored her credentials as a haunted princess of the dark, jaded world called jazz. There’s been considerable doubt cast on some the details of her impoverished and violent childhood, but assuming only a tenth of them are true, she was brutalized. And in adulthood she turned to the self-degradation, first so mellow, of drugs and alcohol. She died in New York City of cirrhosis of the liver, age 44.


Billie Holiday, still from New Orleans (1947)

Photo: via youtube

Here, with flowers, she lip synchs The Blues Are Brewing with Louis Armstrong’s orchestra, from the movie New Orleans (1947)

And here, without flowers but a group of jazz all-stars, is Fine and Mellow, 1957.

Posted by Julie on 04/06 at 04:26 PM
Art & MediaCulture & SocietyPermalink

Friday, April 04, 2008

Pollution Snuffs Floral Scents

New environmental research shows how bad air is very bad news for bees, moths, and the flowering plants they visit.


After a long search for flower scent, this bee is fed up

—but still hungry

Image: Simpson Trivia

Does your life depend on perfume?

Ours does, and, conveniently, we can order another bottle of Mitsouko as needed. But many bees, moths, and other insects must rely on scented flowers—for food.  The flowers they visit also depend on their own fragrances to reproduce, by drawing pollinators in.

A study by Quinn S. McFrederick, James C. Kathilankal, Jose D. Fuentes, published in Atmospheric Environment, shows that air pollution destroys the scent signals of flowers, an effect of bad air that makes pollinators less efficient and plant colonies less robust.

The scholars set up a model to trace how specific scent-producing hydrocarbons released from flowers react with major pollutants in the air: ozone, hydroxyl, and nitrate radicals. They looked at three particular hydrocarbons—linalool, b-myrcene, and b-ocimene—“known to be common scents released from flowers.”  Introducing variables of wind and temperature, they examined how these “perfumes” would change as they encountered polluted air parcels. When the scent compounds react with the pollutants, they begin breaking down fast, becoming unrecognizable to pollinators (as when the ambergris disappeared from Dioressence).


Linalool, a common floral scent compound, breaking down as it reacts with ozone

Image: Courtesy Jose D. Fuentes et. al

The scholars, from University of Virginia’s Department of Environmental Science, write that this feature of air pollution has not previously been studied, though they note that earlier research had found another threat to plants. Floral hydrocarbons (fragrances) also attract natural enemies of herbivores; as airborne pollutants like ozone react with floral scents, the “natural enemies” do battle elsewhere and the herbivores have, as it were, a field day.


Charts showing how the range of floral fragrance compound linalool becomes smaller and smaller with increases in air pollution.

Image: Courtesy Jose D. Fuentes et. al

These charts, based on a Lagrangian model, show how dramatically interaction with air pollution limits the range of floral scents. The “scenario” at top left shows the dispersion of floral scent-compounds in a pre-industrial environment; the one at lower right shows what occurs in a highly polluted setting. The scientists write: “For highly reactive volatiles the maximum downwind distance from the source at which pollinators can detect the scents may have changed from kilometers during pre-industrial times to 200 meters during the more polluted conditions of present times.” Do you smell a problem?

Heads up, Judy Glattstein and other New Jerseyites! “These hydrocarbon–air pollution processes are likely operating in landscapes such as the eastern United States where summertime air pollution levels can become substantially higher than the ones observed in the rural atmosphere away from anthropogenic (a.k.a. human)  influences.”

The scholars note that this impact of air pollution should be harshest on those plants that depend on “specialist pollinators,” since the chemical breakdown of floral hydrocarbons tends to blur fragrances, creating a generic “smell”:  “what was a unique signal in the 1800s has become a general signal.” They also look ahead to research that might compare the olfactory receptors of insects in polluted and non-polluted environments—looking for signs of evolution. A thought: How about comparing the fragrances emitted by patches of city and country larkspur? Might flower scents be evolving too?

Many thanks to Dr. Jose D. Fuentes for sending us the paper.


Posted by Julie on 04/04 at 11:19 AM
Page 3 of 4 pages  < 1 2 3 4 >