Sunday, April 24, 2011

Crab Apple

What’s blooming in the area: White and pink flowered trees, including apples and choke cherry, iris, moss phlox, donkey tail spurge; honey locust and grapes leafing.

Beyond the walls and fences: Cottonwood, western stickseed, hoary cress, tansy mustard, alfilerillo, goat’s beard, native and common dandelions, June and cheat grass; buds on fernleaf globemallow; tree of heaven and Virginia creeper leafing.

In my yard: Sour and sand cherries, Siberian pea tree, lilacs fragrant, tulips, grape hyacinth, baby blue iris, vinca, yellow alyssum, oxalis, small-leaved saponaria; buds on spirea, snowball, peonies and Bath pinks; black locust, catalpa, snowball, forsythia and rose of Sharon leafing; red hot poker, baptisia, sidalcea, Rumanian sage, Saint John’s wort, Maximilian sunflower, chocolate flower and coreopsis coming up; planted sweet alyssum, California and Shirley poppy seeds.

Bedding plants: Pansy, sweet alyssum.

Inside: Pomegranate, zonal geranium, aptenia.

Animal sightings: Heard bees around lilacs; small brown birds were mining seeds under the sour cherry after they decided the flowers weren’t to their liking; gecko ran from the sprinkler; cabbage butterfly, grasshoppers, harvester and small black ants.

Weather: Windy days and warm nights; arroyo bottom bleached out last Sunday; snow remains in Sangre de Cristo; last rain 3/8/11; 14:05 hours of daylight today.

Weekly update: The season for white and pink flowering trees is passing. Some I knew, the apples, the choke cherries, the purple leaf plums. The rest could have been anything I’ve seen sold locally, white flowered plums, sweet or sour cherries. Apricot and Bradford pear flowers came and went.

The pinks are a mystery. In other parts of the country they would be Japanese cherries or flowering crab apples. Here peaches arrive late in the season, and already are leafing, perhaps skipping reproduction this year.

I’ve seen more crabs in local stores than ornamental cherries. When I went to the local hardwares early this week, only one had anything pink, and they were the unlikely eastern redbud and crape myrtle. Either the stock was picked over, or the big boxes have driven the smaller retailers to offer less from fewer suppliers.

Crab apples are the hardest to identify from the road. Although a few varieties are pink, many have pink buds that open white, while others have pink flowers that fade to white. Many species and cultivars that are white from start to finish merge into the general background of anonymous flowering trees.

Thomas Jefferson planted Hewe’s crab apples at Monticello. The juicy fruit, widely used then for cider, is thought to have been a hybrid between the domestic apple brought from England, now simply called Malus domestica, and the native Malus angustifolia.

George Washington asked to have crab apples planted with other trees beyond the south end of his house at Mount Vernon in a grove whose main intent was aesthetic. It’s not known if he meant the pink flowered angustifolia or Hewe’s, which opens pink before turning white. He only specified flowering trees.

The distinction between useful and ornamental crab apples was well established when I was growing up in Michigan. The native Malus coronaria, which grew on the feral land between the housing development and the farms, had nasty thorns. The hard fruit was too sour to eat fresh, although it supposedly produced good jelly. The flowers changed from rose to white.

Flowering crab apples grew in town and were descended from species imported from northeastern Asia. The Siberian crab apple, Malus baccata, with white flowers, was introduced to westerners in 1784. After Perry forced open Japanese ports, nurseries offered Malus floribunda which has rose flowers that turn white. They’ve since been crossed and recrossed to produce the trees currently sold.

The distinction we had between useful and decorative Malus varieties exists here, but is maintained between apples and flowering trees. Orchards lie near the ditches in the front or side yard, often serving as a barrier between the house and the road. Pink crab apples, for only the pink can be distinguished when white flowers abound, usually are grown near the house, often behind a wall that protects their roots and trunks from the hostile winds and unrelenting sun.

While boundaries between ornamental and edible apples exist to most people, there are those who ignore the classification. Some believe flowering trees pollinate their orchards. In Yugoslavia, researchers found they got heavy fruit set on Golden Delicious with floribunda, baskatong and robusta crab apples, but that floribunda’s natural flowering time was earlier than the apple’s. In India, a group found floribunda bloomed with Red Delicious but didn’t produce as much fruit as Snowdrift and Manchurian varieties. Golden Hornet worked best for them with Golden Delicious.

Baskatong is a Malus baccata-adstringens hybrid developed in Canada with rosy purple flowers that fade pink. The pinkish flowered adstringens resulted from crossing a baccata with a domestic apple. Robusta is probably a Malus baccata-prunifolia hybrid from China with pink or white flowers.

Snowdrift was bred by the Cole nursery, perhaps from a white flowered sargentii, while the Manchurian crab apple is a subspecies of baccata with pink buds and white flowers. The white flowered Golden Hornet is probably a Malus zumi selection made by John Waterer and Sons. Zumi itself is possibly a baccata-sieboldii cross from Japan with pink buds and white flowers while sieboldii, sometimes called the Toringo crab, is a Japanese dwarf with pink buds that turn white.

Red and Golden Delicious are the most common apples grown today. Both were introduced by the Arkansas Stark Brothers, the one from an Iowa tree.

Plant breeders have gone farther in eroding the distinction between large sweet and small acrid species. They introduced a crab apple gene into domestic apples to create resistence to the apple scab fungus. Ironically, they only know they used the floribunda clone 821; they don’t know if it was a pure floribunda from Japan or some hybrid spawned by the collectors at Arnold Arboretum who sent them the original seed.

The distinction between an apple and a crab apple may be as much an artifact of culture as the one I grew up with between wild and domesticated crab apples. They’re all members of the same genus of the rose family.

The thing that has always stopped me from using crab apple as the generic term for any unknown pink tree here is that I was always told crab apples prefer acidic soil like that found east of the Mississippi. Either the soil is different closer to the river than it is where I live or hybridization has produced lime tolerant cultivars, or the pink trees remain a mystery.

Notes: For more on the two Delicious apples, see entry on orchards for 14 December 2008.

Cultivar and species information from Liberty Hyde Bailey and Ethel Zoe Bailey, Hortus, 1934; Harrison Leigh Flint and Jenny M. Lyverse, Landscape Plants for Eastern North America, 1997; and Alfred Rehder, Manual of Cultivated Trees and Shrubs, 1947.

Dalzell, Robert F. and Lee Baldwin Dalzell. George Washington's Mount Vernon: At Home in Revolutionary America, 2000.

Gautam D. R., D. D. Sharma and Ali M. Rashil. “Evaluation of Crab Apples for Pollination,” Indian Journal of Plant Genetic Resources 13(2):2000.

Gvozdenovic, D., Z. Keserovic, J. Ninic-Todorovic, and L. Vujic. “Wild Apple Species as Pollinators for Golden Delicious Clone B,” Savremena Poljoprivreda 44(

Hokanson, S. C., W. F. Lamboy, A. K. Szewc-McFadden and J. R. McFerson. “Microsatellite (SSR) Variation in a Collection of Malus (Apple) Species and Hybrids,” Euphytica 118:281-294:2001; on clone 821.

Thomas Jefferson Foundation. “Hewe's Crab Apple,” information and tree available on-line.

Photograph: Pink flowered tree grown lacy under Siberian elms behind a wall outside the village, 17 April 2011.

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