Orchard Care
What's wrong with the apricot orchard?
There are Many Possible Problems
Gleaning from these publications:
What are the possibilities?
Were there blossoms? Yes!
Was there bad weather that prevented the fruit to form? We did have rain on and off, but problems were probably not due to weather. Apricot trees nearby have a bumper crop.
Was it lack of pollination? Probably not. There is a hive on the east side of the Roeding property. Bees were observed in the orchard.
Was there sufficient water the summer before? No! Lack of water interferes with the bud set for the next year. There were buds. However, it's stressful for the tree.
Is it "Biennial Bearing"? No, it has been many years since the trees bore fruit.
Was there fruit set? No, the blooming branches withered before the fruit set.
Plant Pathologists at the UCB sick plants clinic looked at some of the dieback. They said that it wasn't fire blight (apricots don't get fireblight), but some other disease and there was no need to know exactly. Because the solution for most apricot diseases is to prune only in the dry season. Pruning during the wet season causes all kinds of problems. During the winter the various fungi and bacteria get into the pruning wounds and the trees cannot fight them off.
Retired farm advisor, Janet Caprile, visited the orchard some years back and suggested that we might need to spray a fungicide to prevent the blossom rot. In this case, we need to know what exactly is the pathogen responsible?
Remove the diseased wood
We need to cut out the diseased wood in the orchard. Some major branches are failing and need to be cut out. All the little twigs need to go.
The time to do this is after the last rain and after harvest. This can be done in June, July, and August. We may need to paint the trunks with diluted white paint to protect from sunburn.
There was a lovely bloom in 2018, with bees from a nearby hive pollinating the blossoms.
Pedestrian Height Trees?
Can we reduce the size of some of the trees to "pedestrian" size? Over time, the branches have gotten quite long and out of reach of the park visitors. "Pedestrian" trees are trees that have fruit within reach of your normal height visitor.
More and more orchardists are growing shorter trees - at pedestrian height - so they can be more easily harvested and pruned. No ladders means safer working conditions.
UC's "The California Backyard Orchard" has several links under the "Big Picture": "Pruning and Training" - Reasons to prune, the two types of cuts (thinning and heading), training and pruning deciduous trees, ten basics of when/how, pruning abandoned and neglected trees, and more.
For home orchards, some people are recommending very small fruit trees. Grow a Little Fruit Tree is a new book with some old ideas. Pruning in the summer is a method for reducing the vigor to a more manageable level. For apricots summer pruning is strongly recommended, because it reduces the exposure to disease.
Pruning Tips
We will collect some tips here.
Alex Shigo's book helps you understand how your pruning cuts help or hurt your trees.
Pest Prevention by Design (From Kate Nowell, Filoli)
Pest Prevention By Design - Landscapes: Authoritative guidelines for designing pests out of landscapes is the product of a two-year project led by the San Francisco Department of the Environment. The project's goal is to assemble design features and planning considerations that can prevent pest infestations - including weeds - in managed landscapes, and ultimately reduce both labor inputs and pesticide use.
Online tool: The online version contains allows access to all of the details, including downloadable attachments, references, and links to various product examples. Use this version to get the most complete and up-to-date information. [Latest update: 2/6/2020]
Downloadable manual (PDF, 93 pages): We also created a more readable PDF version that can be downloaded and printed. [Latest update: 2/6/2020] May not load properly, so here is the link https://sfenvironment.org/sites/default/files/fliers/files/sfe_th_ppbd-landscapes_030320.pdf
Equipment?
There is an antique tractor and a ring-roller (at Shinn Park).
Water issues
Several gatherings of fruit experts concluded that unless the orchard is irrigated, the trees will be too stressed to provide fruit. Some suggestions:
Dry farming. If the apricots have more space for their roots, they can possibly manage on their own. The suggestion was to remove every other apricot tree.
Mulching with chips or with cover crop. Much experimentation is being done on the advantage of mulching with a cover crop, but the irrigation needs to allow for ring-rolling the cover crop.
Plant different trees that are drought tolerant and have historic value loquat, fig, persimmon, chestnut, and olive. These trees are already on the park property and managing to survive without much irrigation. The loquat and persimmon would probably do better with some irrigation. There is a persimmon near the Roeding residence that provided a good crop a couple years back. The nursery rows of persimmons are starting show stress. The 2020 crop has very tiny persimmons.