What’s happening: First flush of green from bases of needle grass and my neighbor’s globe willow; Russian thistles on the move; Russian olive, juniper and pyracantha berries persist.
What’s still green: Evergreen, yucca, grape hyacinth, Jupiter’s beard, gypsum phacelia, pink evening primrose, broom senecio, snakeweed, chrysanthemum leaves; some grasses; new leaves in black-eyed Susan rosettes; winecup, tansy and tumble mustard germinating.
What’s grey, blue-grey or grey-green: Piñon, four-winged salt bush, yellow alyssum and winterfat leaves; stickleaf germinating.
What’s red/turning red: Cholla, Madonna lily, golden spur columbine, small-leaved soapwort, beardstongue, yellow evening primrose, creeping mahonia leaves; rose and young tamarix stems.
What’s yellow/turning yellow: Globe and weeping willow branches.
What’s blooming inside: Zonal geraniums.
Animal sightings: Hornet on inside porch; small birds out early on peach.
Weather: Warm afternoons chased off by cold winds; snow lingers in Jemez and Sangre de Cristo; last snow 2/4/11; 11:18 hours of daylight today.
Weekly update: Pink evening primroses fit the expectations of Spencerian ecologists who believe species are inherently aggressive and only kept in control by equally aggressive competitors.
Oenothera speciosa is native to tall grass prairies that stretch from Kansas and Missouri down through Texas into Coahuila and Chihuahua. Its branch of the Onagrace family developed in the Madrean Floristic region of today’s intermontane southwestern deserts during the Eocene when the Rockies were first being formed and grasses were evolving some 34 to 54 million years ago. The Oenothera diversified later to the east.
The five-petaled, cup-shaped flowers are white in the northern part of their range, but rosy purple with twice the chromosomes from central Texas south. In particularly hot summers here, they stop blooming in July, but resume with the monsoons and continue even after morning temperatures fall below 32.
The red anthocyanin pigments may be part of their defensive strategy against hostile conditions. The leaves turn burgundy in autumn. This past year some turned color the end of October, just before the hard freeze. More were red after temperatures fell below 20 in mid November. The stems connecting leaves to the crowns of some plants still have a reddish tint.
Despite the frigid winter, my plants kept some green leaves all winter under the protection of dead hollyhock leaves. They contain moderate levels of crude protein which deer and cattle don’t find particularly interesting in the summer. However, come winter, when little else is available, they’re palatable.
Buffalo don’t tend to eat them in summer, but they kill so many other plants with their hooves and mouths that the plants thrive. Their rhizomatous roots spread out into the newly barren areas which they quickly stabilize against the winds. They probably are choked out when the grasses reestablish themselves.
The ability to expand vegetatively is probably another adaption to life on the prairies. Grasshoppers eat the petals, sometimes before the flowers, which only live a day, can attract bees to pollinate them. As it is, the effectiveness of the bees decreases as they move from flower to flower, and the plants must be cross-fertilized to reproduce.
Temperature and day length controls their lives. Jelitto Seeds reports they germinate rapidly at about 68 degrees, then should be moved to a cooler location to grow. Beth Fausey and Art Cameron found nursery plants that spent five weeks at 40 degrees bloomed quickly, while those that weren’t vernalized would only bloom when days were 16 hours long.
For true Spencerians, the most dangerous thing anyone can do is introduce a species into a new environment where there are no natural predators. In the middle 1980's nurserymen were looking for new perennials for the new McMansion suburbs. Wayside Gardens offered its first Mexican evening primrose, Rosea, in 1987, while the more specialist Lamb Nurseries was already selling one as Berlandieri. In the early 1990's, Weiss Brothers added Siskiyou and Woodside White.
When the pink evening primroses were planted in areas where there’s more water like California and east of the Mississippi, the plants became pests. Garden websites are filled with complaints from people who treated them like other herbaceous perennials, only to have them overrun their beds and choke out the peonies, hostas and other more expensive, more cherished plants.
Before the complaints became loud, the species had become so popular with nurserymen, they were sold in the local hardware store in the early 1990's. One person in the village was able to nurture a row on the slope between a chain link fence and a dirt drive that got more than a foot high and were covered with pink flowers from mid May through summer.
I had more problems getting them established in my harsher environment. All the plants I bought, from whatever source, died. Most of the seeds I planted either didn’t germinate or were stolen by ants or birds. The fact my flowers are light pink with deeper colored veins may come from the climate or from the selection sold by Jelitto, the likely German source for the seeds I bought in 2004 and 2005. In 2006 seeds came from Oregon, the home of the Siskiyou mountains. Other years their origin was listed as Holland or the US.
The corollary to the theory of ecological balance is that plants, no matter how successful they may be, usually are unprepared for new threats. In 2003, some kind of metallic green beetle arrived in June. Hordes appeared after I got home in the evening and covered the wood fence, where I tried spraying them. Of course they moved off as soon as I appeared. My only hope was that the residue on the fence would kill or deflect them.
The only thing they ate was the evening primroses. The native white ones never came back, while the cultivated pink ones have only begun to stick their wiry stems up through the bearded iris since 2008. The planting by the village was decimated: a few flowers appeared in 2006 and 2007, then nothing since.
The neon ladybugs were probably primrose flea beetles. Around 2000 Altica litigata began to be reported in large numbers in the southeast. They invaded Dallas in 2002, and were here a year later. Some think they always existed in the wild in weedy Oenothera species that grew around nurseries. One group found, given a choice, they preferred Siskiyou to the natives.
The more confident Spencerians who believe man is the ultimate competitor think the only way to control an invasive species is to introduce its natural predator, preferably after some tests for unintended consequences. The army has been sponsoring research into the use of flea beetles against another member of the Onagraceae, the water primrose. The Uruguayan native has naturalized in the southeast, spread to Europe, and more recently been reported clogging inland waterways in New York and Washington.
One wonders if, when they were reading Principles of Biologu, they also chanced to read Oedipus.
Notes: For complaints, see comments at Dave’s Garden and Garden Web websites, or type in the plant name with the word invasive.
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Photograph: Pink evening primrose leaves surviving under dead leaves, 27 February 2011.