What’s blooming outside: Nothing.
What’s blooming inside: Aptenia, zonal geranium; kalanchoë buds formed.
What’s green and visible in the area: Some honeysuckle leaves; needle grass and other unidentified grasses: agave, yucca, yew, and juniper. Pines and arborvitae are more brown than before; piñon more gray.
What’s green in my yard: Columbine, rose stems, sweet peas, thrift, rockrose, hollyhock, winecup, vinca, Saint John’s wort, coreopsis, horseweed, dandelion, some yellowbrush. Looks like new Mount Atlas daisy seedling; coral bells are turning green.
What’s gray: Buddleia, Greek and fern-leaf yarrow, golden hairy aster, four-winged salt bush. Snow-in-summer and pinks look more alert.
What’s red: Cholla, pinks, small-leaved soapwort; coral, blue and white beardtongues.
Animal sightings: Small birds flitted between peach, cherries and cholla yesterday.
Weather: Some rain Sunday; 3-4" of snow on ground Thursday morning, melted by Friday afternoon, except in shadows. Ground continues to freeze and thaw.
Weekly update: It’s apple pruning time in the valley.
Last Sunday, a man on the back road stood on a short ladder to trim his trees in the mist. Another cut his the last week of January, three weeks ago. Others are probably waiting for thawing ground to stabilize.
My trees are too young. I assumed from the varieties sold at farmers’ markets that Red Delicious was the most commonly cropped apple here. In 2003, I planted three Bisbee cultivars, along with another variety for pollination. They didn’t grow much the first two years, but overcame transplantation shock and developed better roots. Two years ago grasshoppers stripped them, and they put out no new growth in the fall. Last year, they had scattered leaves that began the recovery process.
When I bought two year saplings, they had been trimmed and pruned to leave one strong stem and a few smaller horizontal branches. The central trunk, or leader, does not bear apples. Instead, it functions as a pump, bringing sap up to leaves that fortify it with nutrients created by photosynthesis. Sap returns through the horizontal
branches where it deposits those nutrients in the flowers and fruit.
After apples form, Malus Pumila trees begin their regeneration by forming small leaf and larger bloom buds along the sides of branches. Adolescent trees produce only leaf buds, and concentrate on producing branches, including the small spurs that bear fruit.
When water levels in the soil drop in autumn, roots produce abscisic acid to prepare the terminal bud meristems for winter. Ethylene, another inhibiting growth hormone, prepares the branches to drop their leaves.
When temperatures fall below 55 degrees F, critical processes continue beneath the protective cover of hardened bud scales. When temperatures fall below 35, activities necessary to bud development all but stop.
Scientists aren’t sure exactly what occurs during winter. They only know if the weather warms before trees experience 1,000 hours of cool temperatures, apple buds open later and over a longer period of time, and so miss the flowering time of their pollinating cousins. Poorly formed flowers produce little fruit.
When farmers prune their trees, they take spurs down to three buds, and remove any branches that look like they’ll only produce leaves. Coincidentally, auxin, a growth hormone, is synthesized in terminal buds; when those tips disappear, the tree transfers development energy to the remaining lateral buds.
Red Delicious is notorious for vertical branches that compete with the leader. You can identify unpruned trees in the local orchards by the mantles of 1' to 2' spikes rising from the branches.
If an apple tree remains unclipped, it may lapse into a biennial cycle to only produce fruit every other year. Pruning helps a tree balance its competing requirements. It’s done now, after the worst of the winter cold to prevent freeze damage to the cuts. It needs to be completed before the tree blooms. Exactly when depends on individual growers, and the weather.
Orchards have probably nearly accumulated their chilling time. I think we had over 800 hours between October 16 and the end of November, and have had more than 200 scattered hours since temperatures fell before the solstice.
An experienced eye can see right now, in the cusp of winter, what the crop may be in September. Weather, insects, disease, irrigation, sprays and fertilizer may improve the fruit, but they can’t increase the yield beyond the potential of the existing buds.
As for my trees, I can only hope for good weather to keep them growing to maturity. They have recovered enough to produce the rudiments of spurs. Patience and water are all I can provide, along with snipping the dead tips some sunshiny day.
Photograph: Branches of Red Delicious apple tree, Bisbee cultivar. 10 February 2007.