Sunday, February 24, 2008

Sea Lavender

What’s still green: Conifers, rose stems, yuccas, rockrose, coral bell, sea pink, sea lavender, snapdragon, Saint John’s wort, yellow evening primrose, Mount Atlas daisy, chrysanthemum, some grasses

What’s gray or gray-green: Salt bush, winterfat, snow-in-summer, some pinks.

What’s red: Cholla, some pinks, small-leaved soapwort, coral and purple beardtongues, purple aster.

What’s blooming inside: Aptenia, zonal geranium, kalanchoë, Christmas cactus.

Animal sightings: Quail near cholla, smaller birds in peach and cherries; both were in scavenging bands rather than larger tribal groupings.

Weather: Snow midweek, rain Friday night, freeze and thaw continued on still frozen ground. 11:18 hours of daylight, if we’re lucky.

Weekly update: The freeze and thaw continues to take its toll. My sea lavenders kept their leaves until the heavy snows in December, when all but a few turned brown. When the snows disappeared and the cold remained the first of January, more died. This past week, all but a few hidden under other plants turned leathery with dessication. This is the third time since I planted these perennials in 2000 that some leaves have remained this long.

Chance has always played an important role in their lives. When I designed my garden, I simply said, I don’t have the instincts needed to plan an herbaceous border, so everything pink will go on the east side of the house, the blues on the west, and the gaudy reds, yellows and oranges in the center.

The size and shape of the beds followed the way a backhoe driver had carved, then leveled land from a hillside. On the east, there was only a foot between a retaining wall and the four feet clearance I wanted for the house. On the west a little more that two feet existed before the ground began sloping away.

Once I made my plans, such as they were, I spent several years compiling an impressive list of plants that wouldn’t grow here. Some things were obvious, like the failure of lupines which apparently won’t tolerate clay. Others, seemed more random: red morning glories, bachelor buttons, and larkspur grew to the east, but the more common blue varieties wouldn’t germinate in the west.

Eventually, some large catmints, a caryopteris, and Russian sage established themselves and I needed something to fill gaps between them that was more predictable than the ever migrating flax. Sea lavenders seemed perfect. The taproot could draw water from the narrow strip near the soaker hose, while the foot high branching flower heads could fill the dry space with tiny blue flowers in late summer.

Now, when I look at the surviving leaves, and the still green, grey or red leaved plants to the east, I wonder if my random acts haven’t revealed some hidden order in nature. Most of the plants that still have leaves fall into a few plant families: the Plumbaginaceae of the sea lavender and sea pinks; the Caryophyllaceae of snow-in-summer, pinks and soapworts; the Scrophulariaceae of the beardtongues and snapdragons, and the Saxifragaceae of the coral bells.

Ever since Darwin, scientists have been trying to detect patterns implied by such chance happenings as the survival of leaves on herbaceous plants in climates like mine. However, botanists have never fully agreed on what that taxonomy should be. In 1891, Otto Kuntze angered many of his German peers when he simply renamed many existing plants to clarify problems he found with Linnaeus’ original scheme. Sea lavender went from Statice latifolia to Limonium latifolium.

In 2003, the Angiosperm Phylogeny Group issued its own definitions based on recent findings in molecular biology, especially the characteristics of two chloroplast genes and another gene that coded ribosomes. They grouped Limoniums with the other plants surviving this winter on the east into the order Caryophyllales, which Mary Campagna and Stephen Downie had already discovered had chloroplast rpl16 genes that lacked the usual intron region associated with the development of RNA and protein.

Dolores Lledó’s team noted all the Caryophyllales were adapted to "extreme environments." Her group believes Limoniums developed about six million years ago when the Straits of Gibralter were opening and closing the Mediterranean and creating saline flats to the east. Sea lavenders, which now are associated with Bulgaria, Romania and parts of the former USSR at the eastern end of the sea, developed chalk glands which eliminated the salt they absorbed from the soil.

Ernst Benary tells growers the seeds still need low soluble salt levels in a slightly acid medium to germinate. However, the company suggests nurseries then grow the seedlings in sandy loam. I have the required loam that supports the plant in winter, but I wonder how a seedling sprouted this summer under a dripping spigot.

It wasn’t just the existence of water. When I had my well tested I discovered that the part of the aquifer which I tapped is still very salty from some ancient sea, with 78 units of sodium. Filters have reduced the count to 12, but salts no doubt collected in the area near my hoses before I acted in another random action that supports an unlikely plant within the constraints on unseen rules of natural causality in an extreme environment.

Campagna, Mary L. and Stephen R. Downie. "The Intron in Chloroplast Gene rpl16 is Missing from the Flowering Plant Families Geraniaceae, Goodeniaceae, and Plumbagaceae," Illinois State Academy of Science Transactions 91:1-11:1998.

Ernst Benary Samenzucht GmbH. "R1680 - Limonium Latifolium, Sea Lavender, Statice," available on-line.

Kuntze, Otto Carl Ernst. Revisio Generum Plantarum, 1891.

Lledó, M. Dolores, Manuel B. Crespo, Michael F. Fay and Mark W. Chase "Molecular phylogenetics of Limonium and related genera (Plumbaginaceae): biogeographical and systematic implications," American Journal of Botany 92:1189-1198:2005.

Photograph: Sea lavender leaves, 24 February 2008.

Sunday, February 17, 2008

Braford Pear

What’s still green: Conifers, rose stems, yuccas, coral bell, sea pink, Saint John’s wort, yellow evening primrose, Mount Atlas daisy, some grasses

What’s gray or gray-green: Salt bush, winterfat, snow-in-summer, some pinks.

What’s red: Cholla, some pinks, small-leaved soapwort, coral and purple beardtongues, purple aster.

What’s blooming inside: Aptenia, zonal geranium, kalanchoë; Christmas cactus in bud.

Animal sightings: Sharp-clawed, four-toed paw prints in driveway mud.

Weather: First part of the week I drove out when it was 20 degrees and returned home after temperatures had risen to 50; the ground continued to harden at night, and soften during the day. Night temperatures warmed late in week when a predicted storm didn’t materialize. Some ice remains above bulbs in the garage drip line. Last snow 2/4/08; 10:59 hours of daylight.

Weekly update: In the past few weeks I’ve noticed greater color differences between the small twigs at the tops of trees and their trunks. The variations are most obvious with the Bradford pears growing at the post office, where smooth cinnamon limbs arise from vases of furrowed, gray bark.

Part of the difference is simply age. The outer edge of woody stems accumulates dead cells as the inner tissues continue to produce new layers. Younger brown stems simply haven’t acquired the patina of age.

Weather, like that of the past few weeks, introduces more changes when moisture gathers in crevices between branches, then freezes to pressure brittle limbs until one splits away. The trees build scar tissue necklaces around the breaks, which expands the gray bark up into the more golden branches.

The freeze-thaw cycle also affects the outer water-bearing cells of the woody stems. After enough expansion cycles, the inelastic bark shucks off, exposing the smoother layer behind the outer cork. On some trees at the post office, those exposed cells have whitened, while other tree trunks still have red inlays.

The damage is invisible in April when the trees are covered with five-petaled white flowers, and remains hidden under shiny-topped green leaves in summer. However, trees rarely reach their ultimate age of thirty because the constant splintering kills them.

The problems weren’t foreseen when the USDA released the sterile, fast-growing, pollution-tolerant, narrow, upright trees to nurseries in 1960. It no doubt spread as a replacement for elms that were being devastated in city and city. Some nurserymen later developed new cultivars with more open branches, but some of these went to seed and produced thornier problems.

The agriculture department originally imported Pyrus calleryana seed from China for Frank Reimer, who had discovered it was resistant to the fireblight bacteria that was then destroying Oregon orchards. It eventually became a popular rootstock for the edible fruit tree, Pyrus communis.

It wasn’t until the expansion of suburbs around Washington in the 1950's that department growers saw the callery pear’s potential for beautifying raw, barren streets. According to Theresa Culley and Nicole Hardiman, they selected one tree growing in Glenn Dale, Maryland, from seed collected by Reimer in 1919 near Neijing for cuttings to graft onto other callery pear stock.

When it was released, the USDA recommended that home buyers look for trees that nurseries had pruned and trained into open forms. However, some nurseries may have saved costs by avoiding that pruning, and others may have deliberately trained saplings to a tighter upright form. Still others may have done poor grafts which sprouted scion pears that could pollinate the Bradfords.

Meantime, landscape designers are abandoning the Bradford pear, because it becomes unsightly before it self-destructs and leaves clients unhappy with maintenance problems that lead to replacement costs. I have no idea if the post office will replace these trees when they die. My guess is one has already died and its space been left empty.

However, it is striking that someone here in the valley made a decision to plant white flowering trees on government-controlled land in the first place. The April-blooming Bradford pears are on the north side of the parking lot, while northern catalpas flower in June on the east end. A large bittersweet holds forth in May by the front door. The trees aren’t tall enough to provide summer shade, but right now the just opened sun burnishing red wood at 9am justifies the weekly trek into town to empty junk mail from my PO box.

Culley, Theresa M. and Nicole A. Hardiman. "The Beginning of a New Invasive Plant: A History of the Ornamental Callery Pear in the United States," BioScience 57:956–964:2007.

USDA, Plant Science Research Division. Growing the Bradford Ornamental Pear, Home and Garden Bulletin 154, 1968, revised 1971.

Photograph: Bradford pear at post office, 16 February 2007.

Sunday, February 10, 2008


What’s still green: Conifers, rose stems, yuccas, coral bell, sea pink, Saint John’s wort, yellow evening primrose, Mount Atlas daisy, some grasses

What’s gray or gray-green: Salt bush, winterfat, snow-in-summer, some pinks.

What’s red: Cholla, some pinks, small-leaved soapwort, coral and purple beardtongues, purple aster.

What’s blooming inside: Aptenia, zonal geranium, kalanchoë; Christmas cactus in bud.

Animal sightings: Wherever it is the birds and rabbits are eating, it hasn’t been my yard this past week.

Weather: Snow Monday, very cold Wednesday morning, freeze and thaw ever since; 10:41 hours of daylight today.

Weekly update: Monday, several inches of snow fell on thawed ground. The rest of the week, my boots sank through snow and mud to the freeze line when I trudged in from the drive at night. When I left in the mornings, I negotiated ice-filled, foot-shaped craters. The only consolations for simultaneous thaw and snow was slowly lengthening days and a kalanchoë that’s back in bloom.

A friend brought me the houseplant at work in October 2004. I gave her a smile, gave it a baleful stare, and kept it watered in a florescent-lit office until it went out of bloom. Then, superstitious about living things, I brought the succulent home, and dumped it in with the aptenia on the covered porch. Suddenly, in February it was back in bloom.

The following year it started to bloom in mid-January and continued to produce four-petaled dark-fuschia-colored flowers until September. Last year, the Crassulaceae sent out loose umbrels of color from mid-February to mid-July. This year, it put out its first flowers on January 11.

Kalanchoës are so sensitive to long hours of darkness that growers routinely manipulate the light in their greenhouses to produce flowers for specific market dates. They also follow complex feeding regimens and use growth retardants to keep the flowering stems short. No doubt, perfectly mounded scarlet kalanchoës are being shipped at this very moment for Valentine’s day.

However, it’s not simply the absence of light that matters, but the nature of that light. When I was in grade school, physics was simple: the earth rotated every 24 hours, and orbited the sun every 365 days.

Rainbows represented the full spectrum of visible light and the sun continuously sent the full range of possibilities. However, we only received the full package at noon, which made the skies blue. At dawn and dusk, only the red side of the spectrum could travel the additional distance. The change of seasons was simply a magnification of this pattern: more blue in summer, less in winter.

Understanding physics and light got more complicated after that, but some researchers ignored waves and particles to posit the decline in blue light in winter was what depressed people. Long after I left school, Sterling Hendricks and Harry Borthwick discovered a protein, phytochrome, was the pigment that controlled how plants responded to the far red light between the extreme end of the rainbow and the more famous, invisible infrared light.

No doubt, mathematicians can run calculations that determine the exact amount of darkness required to generate the necessary amount of red light at 6,000' in this part of New Mexico to stimulate kalanchoës to convert from producing dark-green, scallop-edged leaves to reproduction. Botanists have already determined the ratio of far red to in-fared light needed to force a flower to open, close, or remain open despite its circadian rhythms.

On the Tsarantanana massif of northern Madagascar where Perrier de la Bathie found Kalanchoë blossfeldiana growing at 6,666' in 1924, they simply bloom when conditions are right. Mine apparently has reverted, as much as any cutting from a hybrid can revert. Its blooming schedule varies with the kind of November and December we have. Its stems get too long and reach for the light, a sure sign of white to far-red light; the leaves sometimes turn red, signifying too much light; it doesn’t put out as many flowers as it would if it got more blue light. But, it blooms on its own, where in other parts of the country experts tell people to place boxes over their pots to simulate long days or suggest they buy new plants.

So, however much I’ve been complaining about the dreariness of this winter, I have one plant, albeit one indoors, that acts like Pollyanna living in the best of all possible worlds.

Engelmann, Wolfgang, Anders Johnsson, H. G. Karlsson, R. Kobler, M.-l. Schimmel. "Attenuation of the Petal Movement Rhythm in Kalanchoë with Light Pulses,"Physiologia Plantarum 43:68-76:1978.

Pérez, M., M.T. Lao, G. Scherer. "Influence of Different Lamps on the Growth and Development on the Short Day Plant Kalanchoe blossfeldiana," Acta Horticulturae 711 (2006).

Photograph: Kalanchoë growing on my east-facing, inside porch, 5 February 2008.

Sunday, February 03, 2008


What’s still green: Conifers, rose stems, yuccas, coral bell, sea pink, Saint John’s wort, yellow evening primrose, Mount Atlas daisy, some grasses

What’s gray or gray-green: Salt bush, winterfat, snow-in-summer, some pinks.

What’s red: Cholla, some pinks, small-leaved soapwort, coral and purple beardtongues, purple aster.

What’s blooming inside: Aptenia, geranium, kalanchoë; new leaves at top of dried coral honeysuckle stems.

Animal sightings: Small birds, usually alone, in the garden or along the fence.

Weather: Rain Monday, snow Tuesday, cold temperatures and intermittent high winds since; 10:35 hours of daylight today.

Weekly update: This has been one of those weeks that culls the weak and tries the strong. Monday’s rain fell on ground so soft my small car plowed 3" ruts in the drive. The next morning, northwest winds were too strong for me to close my front door from the outside. Since, night time temperatures have fallen to the low teens and the days have resoftened the drive. Even my neighbor’s arborvitaes have shriveled into themselves, turning their brownest faces to the elements.

In summer I look across the road at those evergreens with envy. The one near the back porch drip line has the pleated symmetry of party decorations that store flat, then open into honeycombed paper valentines or pumpkins. The younger two in front flourish with yuccas on the edge of a lawn he sodded in the center of his circular drive.

I’ve hesitated to plant my own, because someone in Texas told me they killed other plants, much like black walnuts. But I look at his vigorous shrubs and yuccas, and wonder what possible damage they could do here.

Anecdotes about plants’ bad habits are difficult to confirm. Where once writers followed standard etiquette that it was better to say nothing than say something critical, now publishers prefer subjects with product tie-ins. In either case, negative qualities were overlooked; if they couldn’t be ignored, plants were discretely dropped from texts. Information is left in the netherworld of rumor and the internet.

One reason for the confusion about arborvitae, commercially sold as Thuja occidentalis, is that it is commonly called white cedar. Red cedar, Juniperis virginiana, does suppress the germination of lettuce seeds in the standard test for allelopathy. Stipe and Bragg found it also inhibited or delayed the growth of finger coreropsis in unburned tall-grass prairies while Ferguson and Rathinsabathi found southern red cedar (Juniperis ciliciola) slowed red root pigweed and hairy crabgrass.

Neither cedar is actually a member of the cedar family; arborvitae is a cypress and the others are pines. The term cedar bark mulch can mean anything, and mulch is intended to suppress weeds. So the world of raw experience, unleavened by controlling theory or systematic experimentation, thrives.

Since I have no intention of growing lettuce - the local rabbits would be far more effective than any shrub in eliminating seedlings - it sounds safe enough to grow along a drive where only weeds and añil del muerto thrive.

However, now that I’ve learned a bit about white cedar, I’m surprised it grows here. Arborvitae’s native range is the Laurentian shield south through the Great Lakes where it thrives in swamps. There, it begins heavy seed production when it’s 30 years old and continues until it’s 75; it can easily live for another 300 years. If anything keeps it in control, it’s hungry white-tailed deer and bagworms.

Evidence from Alaska’s north slope suggests Thuja itself had evolved by the late Cretaceous, 65 to 97 million years ago, when limestone was forming. The genus still tolerates cold. In the wild, it can adapt to drought conditions, and its genetic structure has made it easy for nurserymen to create more than 100 cultivars attuned to different markets. However, the only thing I see I have that it likes is calcareous soil; my neighbor’s shrubs have certainly been highly offended by the recent cold spell.

Whether or not I experiment with arborvitae this spring depends on factors I can’t control: the amount of moisture left in the ground in the spring and the buying habits of companies that supply the local garden centers. One thing I can predict: I won’t be able to try southern red cedar mulch in the area where pigweed sprouts because the winds will blow it away within a week.

Ferguson, James and Bala Rathinsabathi. "Utilizing the Weed Suppression Capacity of Selected Tree Species in Weed Control in Woody Ornamental Species," Florida Nursery, Growers and Landscape Association report, available on-line.

LePage, Ben A. "A New Species of Thuja (Cupressaceae) from the Late Cretaceous of Alaska: Implications of Being Evergreen in a Polar Environment," American Journal of Botany 90:167-174:2003.

Nesom, Guy. "Northern White Cedar," USDA plant guide, 2003, available on-line.

Stipe, Dan J. and Thomas B. Bragg. "Effect of Eastern Red Cedar on Seedling Establishment of Prairie Plants," North American Prairie Conference Proceedings 11:101-102:1988.

Photograph: Neighbor’s arborvitae, 2 February 2008, growing under a drip line where household debris collects.