Sunday, June 27, 2010

Baby's Breath

What’s blooming in the area behind the walls and fences: Tea roses, Spanish broom, silver lace vine, honeysuckle, trumpet creeper, red yucca, Russian sage in town, larkspur, datura, Shasta daisies, alfalfa, onions; buds on tall yuccas; peas for sale.

Outside the fences: Tamarix, Apache plume, cholla, Queen Anne’s lace, tumble mustard, fern-leaf and leather-leaf globemallows, velvetweed, scarlet beeblossom, white evening primrose, milkweed, bindweed, bush morning glory, Dutch and purple clover, buffalo gourd, Indian paintbrush, goat’s head, wooly plantain, alfilerillo, silver-leaf nightshade, native dandelion, goat’s beard, hawkweed, paper flower, strap-leaf and golden hairy asters; buds on white sweet clover.

In my yard looking north: Catalpa peaked, miniature roses, daylily, red hot poker, golden spur columbine, Harweig evening primrose, butterfly weed, chocolate flower, blanket flower, coreopsis, Parker’s Gold yarrow, Mexican hat, black-eyed Susan, anthemis, orange coneflower; reddening sour cherries.

Looking east: Dr. Huey rose, hollyhock, winecup, sidalcea, coral bells, Jupiter’s beard, baby’s breath, Bath’s pink, snow-in-summer, bouncing Bess, coral beardtongue, last year’s pink snapdragon, sea pink, Maltese cross, pink salvia, pink evening primrose.

Looking south: Blaze, prairie and rugosa roses, sweet peas; first ripe raspberry.

Looking west: Catmint, blue speedwell, blue salvia, spurge, blue flax; buds on lilies, sea lavender and ladybells.

Bedding plants: Moss rose, nicotiana, tomato.

Inside: Aptenia, zonal geraniums.

Animal sightings: Red snake, humming bird, geckos, cabbage butterfly, bees on catmint and columbine, small grasshoppers, large black harvester and small red ants.

Weather: All week it’s wanted to rain, but all the clouds produced were high winds and occasional droplets; last rain 05/14/09; longest day was 14:37 hours; 14:36 hours of daylight today; the fire in the Jemez has now burned more than 16,000 acres.

Weekly update: Baby’s breath is always described as delicate or dainty or airy. If the plant is noticed, the leaves are described as sparse or gone by the time it blooms. These are people who go to the ballet and watch the pas de deux, but never see the calves of the male dancers.

The thing I’ve noticed most since I put some Bristol Fairy plants in the wind blown pseudo-alpine bed is the muscularity of the plants. They aren’t at all like the sea lavenders with their wide tutu of green leaves that hug the ground, so narrow stems can rise from the center to support their myriad sprays of flowers in high open second.

Baby’s breath’s in the carnation family and it looks like the florist’s plant when it emerges with narrow grey leaves that look too much like heath asters. When the stems do appear, they’re thick and swollen at the joints where the leaves peel back. It’s only after the heads have fully expanded that the tiny, double white flowers dominate the scene.

Garden guides tell the unwary how simple they are to grow from black bean-shaped seeds in limey soil. Seed companies imply they’ll bloom the first year. Notes to professional growers warn seedlings are highly variable and they should rely instead on grafted plants or cuttings of some kind.

As children many of us were seduced by the promises of annual recitals staged by local mall dance studios. When I walked into a class in Philadelphia and the instructor showed the first combination, it all look quite familiar and doable - until the better trained dancers lead the line and I realized the difference between my childhood experience and dancing.

My baby’s breath is a triumph of engineering and adaptation. Gypsophila paniculata grows from Siberia west through the Caucasus and up into eastern Europe where, Maria Shahgedanova says, it’s adapted to the open steppes by turning its stalks into tumble weeds. The root can reach down more than ten feet to both anchor it and find water.

On this continent, James Pringle says that while it can naturalize in the east, it has become abundant in parts of the west where it’s treated as a noxious weed. In Saskatchewan, the perennial has invaded disturbed areas dominated by bunch grasses.

Bristol Fairy is a double form of the five-petaled flower that was introduced in 1928 and became the trade standard, even though it still behaves like a wild plant. Only a quarter of its seeds will produce fully double plants, it will only bloom when it’s grown in conditions that ape its original habitat, and the flowers refuse to all open at the same time.

The roots need to be chilled each winter, the flowers only appear when days grow longer, and won’t appear if they get too warm. In Florida in the 1970's, growers dug the roots every summer and knew incandescent lights at night would speed their bloom, even though they couldn’t afford the electric bills. In Japan, Motoaki Doi’s team found different strains of Bristol Fairy respond differently to the same stimuli so it can be a waste to run the generator.

Fortunately, after three years of settling in, New Mexico’s highly variable weather produced naturally what all those professionals seek. I first noticed buds on my plant on June 5. The flowers didn’t start to appear until four days before the solstice. In this week of the longest days of the year, the tiny stems holding the separate flowers are widening and new flowers are appearing to replace those already spent in a net of tulle.

Sometimes, watching an amateur or provincial company do Swan Lake is more satisfying than more famous professionals exhausted by touring and bored by repetition. And sometimes, nature shares its bounty with anyone willing to put something in the soil, add water and wait in the wings.

Notes:
California Department of Food and Agriculture. "Baby's breath [Gypsophila paniculata L. var. paniculata]," weed info website.

Doi, Motoaki, Eiko Morita, Nobuyoshi Ogasawara, Yasuka Takeda, and Tadashi Asahira. "Growth and Flowering of Gypsophilla paniculata L ‘Bristol Fairy’ Selections as Influenced by Temperature and Shoot-Rate Interactions," Japanese Society for Horticultural Science Journal 60:119-124:1991.

Pringle, James S. "Gypsophila paniculata Linnaeus," efloras website.

Raulston, J. C., S. L. Poe and F. J. Marousky. "Cultural Concepts of Gypsophila paniculata L. Production in Florida," Florida State Horticultural Society Proceedings 423-428:1972

Shahgedanova, Maria. The Physical Geography of Northern Eurasia, 2003.

Photograph: Looking up at Baby’s breath from the leaves before the flowers are fully open, 23 June 2010.

Sunday, June 20, 2010

Garlic

What’s blooming in the area: Tamarix, tea roses, Apache plume, Spanish broom, silver lace vine, honeysuckle, red yucca, onions, Queen Anne’s lace, tumble mustard, few hollyhocks, larkspur, fern-leaf globemallow, velvetweed, scarlet beeblossom, milkweed, bindweed, datura, alfalfa, Dutch clover, purple loco, native dandelion, goat’s beard, hawkweed, paper flower; brome, rice, and three-awn grasses; corn up a foot; first alfalfa cut; buds on Virginia creeper; few native sunflowers up; cottonwood cotton blowing.

In my yard looking north: Catalpa, miniature roses, daylily, red hot poker, golden spur columbine, Harweig evening primrose, butterfly weed, chocolate flower, blanket flower, coreopsis, Moonshine yarrow, Mexican hat, black-eyed Susan, anthemis; nasturtiums up; yellow cosmos producing second leaves; red sour cherries.

Looking east: Dr. Huey rose, winecup, coral bells, Jupiter’s beard, baby’s breath, Bath’s pink, snow-in-summer, bouncing Bess, coral beardtongue, pied and last year’s pink snapdragons, sea pink, Maltese cross, pink salvia, pink evening primrose; buds on sidalcea; Sensation cosmos coming up reluctantly.

Looking south: Prairie and rugosa roses, sweet peas.

Looking west: Rumanian sage, purple salvia, catmint, Husker’s Red beardtongue, spurge, blue flax; buds on sea lavender and speedwell.

Bedding plants: Zonal geraniums, moss rose.

Inside: Aptenia.

Animal sightings: Rabbit, birds in cherry, gecko, cabbage butterfly, bees on catmint, large black harvester and small red ants.

Weather: Some mornings cooling off to mid-40's, others staying warmer; fire in the Jemez has been burning more than a week, sending pink smoke across the valley; last rain 05/14/09; 14:37 hours of daylight today.

Weekly update: Garlic is one of those plants I never could grow. Both here and in Michigan, I was too cheap to order something from a catalog, so planted bulbs I bought loose in the supermarket. A few would come up, but die in the heat. I finally stopped trying.

Then, about the time I started this blog in the spring of 2006, I was being invaded by grasshoppers. When someone suggested garlic oil, I dropped cloves around the garden thinking maybe evaporation would work More practically, I bought a pesticide at the local big box.

Two years later, in 2008, I saw something that looked like garlic leaves in the back drip line in March, near the cherry and apples in May. In June, the quail kicked up something that looked like a bulb under the locust. I dismissed the similarity. I’d scattered the cloves on the surface, not buried them.

Last February, I saw something under the cherry. This year, there were suspicious leaves in back in February, under a sand cherry in April, and under some apples in May. Last weekend I looked out the window and saw, from above, what definitely looked like a garlic bulb partly uncovered under the cherry. The lower leaves were browning and the stalk tipping.

Allium sativium is one of those plants that’s become so cultured by man, it no longer can reproduce itself by seed. Botanists believe the original may have been Allium longicuspis that produces seeds between the Kopet Dag and Tien Shan mountains in central Asia. A form that no longer develops seeds, but still flowers on a looping stem and produces tiny bulbils is found in eastern Europe and parts of Iberia. The Mediterranean garlic we eat today no longer bolts, produces more cloves and stores longer.

Garlic is sensitive to differences in soil, temperature, moisture, altitude - in short, all the elements in its habitat. Plants that bolt in Spain won’t in Japan. Cloves grown for cooking in southern California weren’t likely to do well in Michigan in the 1980's. Since the early 1990's, most inexpensive garlic comes from China, and isn’t any more likely to thrive in New Mexico.

Seed catalogs offer garlic in the spring, and imply it should be planted early in the season. I tried. A few will germinate. However, garlic is a lily that prefers to be planted in the fall when it develops roots to winter over. When late winter temperatures climb into the low 40's, garlic loses its dormancy and grows best when temperatures are in the mid 60's. When days grow longer and temperatures rise, the leaves begin to die and the bulbs ripen like the one outside my window. It doesn’t follow normal farm and garden planting cycles.

The best know area garlic grower is Stanley Crawford, who moved to the Dixon area in the late 1960's when artists and "hippies" were gentrifying villages on the roads to Taos. His first plants came from some dug in the spring by a friend from an apple orchard in the early 1970's. Another gave him some garlic tops to try from another orchard.

Nothing much happened with either. Then, a few years later, he discovered them growing. It takes bulbils around three years to grow large enough to sprout.

He noted that his rocambole garlic resembles that sold in braided clusters from México, and wonders if his came with the conquistadores. It’s certainly true, Spain is the origin of New World garlic. Eugene Lyon has found shipping records that show garlic was included in the food supplies of the Nina on Columbus’ third voyage in 1498. By the time Hernán Cortés arrived in México in 1519, it was being sold in the Aztec markets of Temixtitan.

The bulb is one of the plants Gaspar Pérez de Villagrá thought the Santa Domingo could grow when he arrived here with Juan de Oñate in 1598. Alonso de Benavides reported it growing in Santa Fé in the late 1620's. However, by the time the interior department was surveying the area in the depression, no garlic was mentioned, although Don Usner did find two women who remembered ajo growing around Chimayó when they were children.

Between Benavides and Amada Trujillo and Tila Villa, the Spanish had been evicted and returned, famines had come and gone, and trade with northern México had been disrupted. Seed stock could have been eaten, new bulbs that could grow here could have become unavailable, and people may simply have forgotten how to grow it.

The common diet still included the conquistadores’ wheat, but the rest was adopted from the pueblos, corn and beans with chile as the primary spice. What garlic plants were grown or bought might have been medicinal and too few to be noticed by outside observers.

Dixon was organized as a land grant in 1725. Any crops were either brought from another settlement in the Española valley after the reconquest or came from México with the annual cordones to Chihuahua, just north of where garlic grows today from Zacatecas south to Puebla.

The Embudo Land Grant, that includes Dixon, was nullified by the federal government in 1898, throwing land ownership into question about the time Stark Brothers’ Delicious apple was stimulating the development of large orchards in the west.

It’s just as likely, someone in the recent past bought one of those riastras from the mountain valleys of México, broke out the cloves and planted them in a Dixon orchard.

It doesn’t really matter. His garlic is one that grows in the rio arriba, not in full sun as the guides all say, but under trees and in grasses, like mine which came from a grocery that caters to local Spanish speakers and grows unaided where it pleases.

His customers tell him his tastes much better than what they buy in stores. I’ll never know the taste of mine; when you have only a few plants you tend to think of them as pets.

Notes:Benavides, Alonso de. Memorial que fray Juan de Santaner de la orden de S. Francisco presenta a la Magestad Catolica del Rey don Felipe Quarto, 1630, republished 1996 as A Harvest of Reluctant Souls, translated and edited by Baker H. Morrow.

Cortés, Hernán. Letter to Charles V, published as second letter in Hernan Cortes Letters from Mexico, translated by Anthony Pagden, 1986 edition.

Crawford, Stanley. A Garlic Testament, 1992.

Etoh, Takeomi, Hideki Watanabe, and Sumio Iwai "RAPD Variation of Garlic Clones in the Center of Origin and the Westernmost Area of Distribution," Kagoshima University, Faculty of Agriculture Memoirs, 37:21-27:2001, compares Iberian and central Asian garlic.

US Department of Interior, Tewa Basin Study, volume 2, 1935, reprinted by Marta Weigle as Hispanic Villages of Northern New Mexico, 1975.

Usner, Don J. Sabino’s Map: Life in Chimayó’s Old Plaza, 1995.

Villagrá, Gaspar Pérez de. Historia de la Nueva México, 1610, translated and edited by Miguel Encinias, Alfred Rodrígue and Joseph P. Sánchez, 1992.

Photograph: Garlic, 15 June 2010.

Sunday, June 13, 2010

Baptisia

What’s blooming in the area: Tea and double pink shrub roses, Apache plume, silver lace vine, tumble mustard, few hollyhocks, fern-leaf globemallow, oxalis, velvetweed, white evening primrose, scarlet beeblossom, nits and lice, milkweed, bindweed, datura, alfalfa, Dutch and purple clovers, purple loco, sweet pea, native dandelion, goat’s beard, hawkweed, paper flower; brome, rice, and three-awn grasses; buds on Virginia creeper.

In my yard looking north: Catalpa, daylily, red hot poker, golden spur columbine, Harweig evening primrose, chocolate flower, blanket flower, coreopsis, Moonshine yarrow, Mexican hat, anthemis.

Looking east: Dr. Huey rose, winecup, oriental poppy, coral bells, Jupiter’s beard, first coral beardtongue, bouncing Bess, pied snapdragon, Maltese cross, pink salvia, pink evening primrose; snow-in-summer, Bath’s pink and sea pink peaked; buds on sidalcea; zucchini seeds up.

Looking south: Prairie and rugosa roses.

Looking west: Rumanian sage, purple salvia, catmint, Husker’s Red beardtongue, blue flax; buds on sea lavender and speedwell; daffodil, tulip and grape hyacinth leaves disappearing.

Bedding plants: Zonal geraniums, moss rose.

Inside: Aptenia.

Animal sightings: Gecko, cabbage butterfly, bees on pink evening primrose, large black harvester and small red ants; hear crickets.

Weather: High temperatures and bad air during week, high winds yesterday; another fire in the Jemez; last attempted rain 05/28/09; 14:36 hours of daylight today.

Weekly update: Whatever was I thinking? Any gardener who hasn’t uttered those words, simply hasn’t been at it very long.

I planted the bare root of a Baptisia australis in May of 1998. Most guides say it reaches its flowering prime in three years, even if grown from seed. I had no flowers until 2007, and this is the first year I can say that it begins to resemble something one would encourage.

Only now, I can’t remember why I wanted it.

Looking back at the pictures of the plant in the catalog I used to order the plant, the false indigo looks like a large clump of lupine. What I have is something closer to a cluster of dark blue sweet peas standing atop tall, single stems of clover.

Looking at another catalog from that time, I see the perennial described as "native prairie." I’ve never been interested in developing the west side of my house as a natural garden, but I may have been looking for plants that could survive prairie conditions.

I’ve since learned, the word prairie is used both to refer to a general environment that spreads west from the Appalachians to the Mississippi valley and to the grasses and their associated plants growing in that area.

This Baptisia is native to the waterways of the prairie, not to the grasslands. To survive the variable conditions of its home range, it has a deep taproot which allows it to survive drought. As a legume, it also attracts microorganisms that fix nitrogen.

However, when the climate is dry and the soil sandy, it takes time for the root and its supporting environment to develop. It was only after the peculiar weather of the past two years that the woody crown put up more than a few stems.

Conservationists who want to use its seeds in tall grass prairie restoration projects have been frustrated by their unpredictable germination. Tony Avent noticed fresh seed emerges quite easily, a sentiment echoed by eastern gardeners who constantly pull out seedlings. However, as soon as the yellowish-brown kidney shaped beans dry, Avent found he had to treat them with boiling water to break their dormancy.

Thomas Boyle and Kristen Hladun tried every scarification method known to botanists and found sulphuric acid works best. Researchers at the Chicago Botanic Garden reasoned that since the local prairie was maintained by fire and not chemists, maybe smoke would help conservationists with their restoration projects. Baptisia australis was one of the plants they tested that did indeed respond to aerosol smoke.

The grey green plant found other ways to survive the grassland habitat, including developing bitter tasting alkaloids that deter grazing. Still, the seed pods are invaded by weevils and the flowers are eaten by blister beetles, two pests that keep it in check in its home range but are missing in those lush gardens overrun by the tiny seedlings each spring.

The large pods are another of its defensive tricks. When the seeds mature, they rattle inside the blackening case. Some have suggested the sound, especially along a river, would startled people into thinking a snake was present. However, the Cherokee weren’t fooled long, They used the roots and leaves for a dye and medicine.

The other phrase I saw in the old catalog that might have attracted my interest is "bushy, shrub like habit." While I didn’t want a prairie garden on the west side of my house, I did want a row of shrubs with blue colored flowers that would make the narrow area that snaked along the irrigation hose look larger.

When I think of a shrub, I think of a plant that has many branches like the Russian sage and the caryopteris growing there, or that produces a great mound like the Six Hills Giant catmint. My Baptisia instead is a narrow clump of stalks that rise several feet before spreading into a foot wide canopy of subdividing trifoliate leaves that disappears every winter.

One would get the effect of a copse in its native riparian environment when multiple plants or the rhizomatous offspring of the parent stretched along the water. Indeed, it was a clump of plants that were used to create the how the photograph that tempted me to order.

As my plant emerged the beginning of May and started blooming the end of the month, I began to wonder if it had finally matured, or if it was one of those plants that slowly build to a climax, then die. When Avent went looking for members of the genus, he found plants were still growing where they were spotted decades before and others have said australis clumps have lived more than 20 years without dividing.

If it returns next spring, and it is always one of the last things to break ground, I’ll know that it has finally become established. If I don’t see it, I won’t know if this weather finally did it in or if it had reached the end of its natural life.

I also don’t know if I would replace it. I’ve gotten used to its tall summer presence, but I’m not sure purple sweet peas and clover leaves are worth waiting a decade.

Notes:Catalogs from Milaeger’s Gardens (1993) and White Flower Farm (1998). Comments on "Indigo Baptista - Transplanting" and problems with seedlings at gardenweb.com.

Avent, Tony. "Baptisia - Revenge of the Redneck Lupines," Horticulture Magazine, June 2002.

Boyle, T. H. and K. Hladun. "Influence of Seed Size, Testa Color, Scarification Method, and Immersion in Cool or Hot Water on Germination of Baptisia australis (L.) R. Br. Seeds,"
HortScience 40:1846-1849:2005.

Forsberg, Britt, Lara Jefferson and Karyi Havens. "Effects of Smoke on Prairie Seed Germination," Chicago Botanic Garden.

Hamel, Paul B. and Mary U. Chiltoskey. Cherokee Plants and Their Uses -- A 400 Year History, 1975.

Photograph: Baptisia australis in front of Six Hills Giant catmint, 6 June 2010, just before the heat finished it off for the season.

Sunday, June 06, 2010

Weigela

What’s blooming in the area: Catalpa, Russian olive, tamarix, Austrian copper and double pink shrub roses, Apache plume, yellow potentilla, silver lace vine, narrow-leaved yucca, red hot poker, peony, tumble mustard, hollyhock, fern-leaf globemallow, oxalis, white evening primrose, scarlet beeblossom, nits and lice, bindweed, datura, purple locust, alfalfa, Dutch and yellow sweet clovers, purple loco, sweet pea, purple salvia, native dandelion, goat’s beard, hawkweed; June, brome, needle, rice, and three-awn grasses; buds on milkweed and stickleaf; lamb’s quarter up; needle grass seeds letting go.

In my yard looking north: Spirea, iris, golden spur columbine, Harweig evening primrose, chocolate flower, blanket flower, coreopsis, perky Sue, Moonshine yarrow; buds on daylily and anthemis.

Looking east: Dr. Huey and Persian yellow roses, winecup, oriental poppy, coral bells, Jupiter’s beard, snow-in-summer, Bath’s pink, sea pink, pied snapdragon, Maltese cross, pink salvia, pink evening primrose; buds on raspberry and coral beardtongue; pods on Siberian pea.

Looking south: Miniature rose, beauty bush; bundle weed and zinnia seeds planted last Sunday up.

Looking west: Rumanian sage, catmint, baptista, blue flax, vinca, chive; buds on sea lavender; perennial four o’clock up.

Bedding plants: Zonal geraniums.

Inside: Aptenia.

Animal sightings: Jack rabbit in arroyo, hummingbird, gecko, cabbage butterfly, bees on catmint, baby grasshoppers, large black harvester and small red ants, mosquitoes, flies; hear crickets.

Weather: Smelled Jemez fire Tuesday night; temperatures getting into 90's in afternoons; last attempted rain 05/28/09; 14:31 hours of daylight today.

Weekly update: This is the time we should be looking at our roses and watching vegetables germinate. Instead, everyone’s complaining the iris didn’t bloom and wondering when they should have put out their tomatoes.

Shrubs have had a particularly trying year: winter cold killed branches on any that were weak or tender, but icy moisture encouraged the roots of some to put out new growth. The reasons depend on the plant: buddleias are herbaceous in much of the country, but the spirea that died back has never done well.

My weigela’s problems are both genetic and historic. I planted something called "pink flowering" in 1997 that never did as well as the nearby beauty bush. The leaves were killed by cold in late April of 2000 and the wind battered and wilted them in May of 2003.

Then the grasshoppers hit the summer of 2005 and not only ate the leaves, but apparently any latent growth that had formed. The next spring, lots of stems were still alive but had no leaves. New leaves did finally come up from the base. It's limped along since with a few stems surrounding a clump of pealing, dead wood I never had time to prune out. Last year the flowers were pale, almost white.

Now, this year, no flowers, and after a month, there are leaves on only four stems. However, last weekend there was lots of new growth at the crown.

The caper family member should do better here. Weigela florida grows from Inner Mongolia through northeastern China into Korea. However, a group at Iowa State found plants grown from tissue culture were more like to produce branches than those grown from cuttings which tended to let the primary stems dominate.

Sydney Waxman found the length of day light was also important in producing good shrubs from cuttings. If the weigela stock was growing in long day conditions, it produced more roots if the cutting was also grown in long days.

That may sound somewhat self-evident but it means nurseries producing commercial plants can only make cuttings at certain times of the year, and those times may not coincide with their production schedules. Since I bought my plant at the local hardware, I assume the least expensive, most conventional propagation methods were used, and the plant I got was inherently weak.

At the time Waxman was doing his research at Cornell, the Nitsches in France determined weigela’s sensitivity to daylight was located in the youngest leaves. Normally, when days grow shorter, the shrub begins to prepare for winter. However, if the leaves are removed the plant ignores day length and continues producing new growth.

That year the grasshoppers attacked, they fooled by plant into continuing growing into the fall, making it even more vulnerable to winter injury than usual.

Last year’s conditions were much like this year: a short period between chilly morning temperatures and a hot June, with an early drought. Last year the monsoons failed to maintain normal plant health and the winter had colder, wetter stretches than usual. Last year’s new growth, which would produce this year’s flowers, probably didn’t develop or died, and the older, grey stems are having problems producing leaves.

But, now that the days are longer, those scarce first leaves are able to send messages to the plant’s nerve center, and new vegetative growth is appearing. I may not get to see any pink funnels this year, but I am, once again, able to watch nature adapt to unexpected problems with biological mechanisms developed for another world.

Notes:
Ghrist, Angela C., Loren C. Stephens, and Jack L. Weigle. "Growth Habit of Weigela florida as Affected by Stock Plant Propagation History," Journal of Environmental Horticulture 9:123-127:1991.

Nitsch, J. P. and Colette Nitsch. "Photoperiodic Effects in Woody Plants: Evidence for the Interplay of Growth-Regulating Substances," Conference on Photoperiodism, 1957, proceedings published as
Photoperiodism and Related Phenomena in Plants and Animals.
Waxman, S. The Development of Woody Plants as Affected by Photo-Periodic Treatments, 1957, described by Nitsch and Nitsch.

Photograph: Weigela coming up from roots, 31 May 2010.