Sunday, March 04, 2007

Honeysuckle

Signs of spring: Leaf buds visible on tea roses; tumble mustard growing in my neighbor’s drive; purple aster leaves more obvious. Home Depot and Lowe’s have shipments of trees, bareroot shrubs, bulbs and Ferry-Morse seeds.

What’s blooming inside: Aptenia, zonal geranium; kalanchoë; honeysuckle buds.

What’s green and visible in the area: Some honeysuckle leaves; unidentified grasses: agave, yucca, yew; arborvitae, piñon, juniper and other pines.

What’s green in my yard: Columbine, rose stems, Apache plume, thrift, rockrose, coral bells, hollyhock, winecup, yellow evening primrose, horseweed, Mount Atlas daisies, black-eyed Susan, Mexican hat, chrysanthemums, some yellowbrush. Moss growing on the west side of the garage where ice lingered.

What’s gray: Four-winged salt bush, snow-in-summer, pinks; Greek and fern-leaf yarrow, golden hairy aster.

What’s red: Cholla, pinks, small-leaved soapwort; coral, blue and white beardtongues.

Animal sightings: Horses in the village. The other local hardware, the one that sold sonar devices to repel gophers, now has traps instead.

Weather: Ground remains frozen; cold winds, sometimes strong; light dusting of snow before dawn Saturday; full moon.

Weekly update: Linnaeus lived in a Manichaean world where things were either annual or perennial, coniferous or deciduous.

Here in New Mexico we have semievergreens that lose their leaves farther north, but keep them here most winters. Last weekend many of the remaining coreopsis and vinca leaves were killed by cold winds that followed the disappearance of their protective snow cover. Leaves of pinks, columbines, and beardtongues remained dark maroon.

Dark, weatherbeaten leaves on Japanese honeysuckle vines in the village looked greener on a coyote fence behind protective boulders where Queen Anne’s Lace bloomed last summer. The fence fronts a ditch. Behind it lies an orchard and French-influenced territorial style farm house on grass flats that stretch back towards the river.

After watching those vines bloom year after year, I bought a honeysuckle plant last spring for my inside porch where the more common philodendron and pothos wouldn’t grow. When I got home, I discovered I’d bought coral honeysuckle by mistake.

Honeysuckle has two species diffusion centers: one in northeast Asia of Manchuria, China, Korea and Japan that begat the village vine, Lonicera japonica, the other in the eastern United States that produced my Lonicera sempervirens. Some 65 genera share this bipolar distribution.

The honeysuckle family emerged during the late Cretaceous, some 65 to 97 million years ago when polar water temperatures were some 35 degrees higher than today. Arctic sea temperatures rose 3 degrees during the Eocene when forests spread to the poles some 55 million years ago and the primary Caprifolia genera began to evolve. Many believe the temperature spike was caused by an increase in carbon dioxide.

Forests that had spread through the northern hemisphere receded when northern ocean temperatures dropped to current levels 25 to 34 million years ago. Glaciers reformed and disrupted the forest corridor, thus isolating plant communities.

Temperatures rose to levels slightly less than those at the end of the Eocene 5 to 25 million years ago, and species again diversified during the resulting Miocene as plants adapted to changing conditions. Many plants’ DNA shows they now share more with surrounding plants than with their ancestral genera. The village honeysuckle has sweet, night blooming flowers that attract pollinating insects. The native has odorless red funnels to lure hummingbirds.

When the two honeysuckles compete for resources, Japonica is more successful. It apparently has retained more of its Eocene heritage. It remains active so long as predawn temperatures don’t fall below 26 degrees. The stems begin elongating when soil temperatures are between 37 and 46 degrees. New growth appears when air temperatures are between 42 and 85.

More important, it tolerates higher levels of carbon dioxide, a trait that may be traced to surviving the global warming that ended the Cretaceous. Cold-tolerant leaves use the gases released when other plants die in the fall to maintain their color during the winter. In the valley, more gases are released when people use wood stoves and burn weeds.

At the moment my plant is the more precocious. Last weekend, it put out new leaves. This week the stem began lengthening and Friday the leaves spread to reveal flower buds.

My porch shares many characteristics with the outside environment, including the quality of light, longer hours of daylight, changing sun angles and drafts. However, the porch is warmer, with a minimum temperature in the low 40's and highs last week in the mid-80's. Plants also get more reliable water.

It won’t be long before outside temperatures rise, and Japanese honeysuckle growth will be visible from the road. Soon after, temperatures on my porch will increase, and my plant will retard its growth to protect itself.

In the meantime, I watch the two wintergreens recover from winter and think about that other Asian-American disjuntion archeologists want so badly to explain: the movement of Clovis people to Curry County 10,000 years ago when temperatures were reaching modern levels.

Notes:
Bell, Charles D. and Michael J. Donoghue. "Dating the Dipsacales: Comparing Models, Genes, and Evolutionary Implications," American Journal of Botany. 92:284-296:2005.
Schierenbeck, Kristina A. "Japanese Honeysuckle (Lonicera japonica) as an Invasive Species; History, Ecology, and Context," Critical Reviews in Plant Sciences 23,:391-400:2004.
Wen, Jun. "Evolution of Eastern Asian and Eastern North American Disjunct Distributions in Flowering Plants," Annual Review of Ecology and Systematics 30: 421-455:1999.

Photograph: Coral honeysuckle on inside porch with new leaves opening to reveal flower buds, 2 March 2007.

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