Pacific Crabapple Project
The Pacific Crabapple Project
Native Apple Rootstock Research and Development
With support of the Western Sustainable Agriculture Research and Education (SARE) program, we are excited to announce the launch of an on-farm research project that could hold the promise of new rootstock options for apple production – including options with greater disease resistance, tolerance for wet soils, and climate adaptability! Watch this page for regular updates on this project.
(Photo by Gordon Leppig and Andrea Pickart)
Why We Need a Rootstock Revolution
October 29, 2017
Grafting apple trees onto specific rootstocks for size control, early bearing, and pest and disease resistance has been practiced for hundreds of years. Ultimately this practice was formalized in Europe during the mid-1800s with the selection of specific named (or more accurately, numbered) rootstock cultivars. By the 1970s and 80s apple rootstock development peaked with research programs in new regions including Russia and the United States (notably from the Cornell/USDA research station in Geneva, NY).
Despite this work, today the diversity of commercially available rootstocks remains
extremely limited. Practically speaking, the most widely available options are the Geneva selections, the Malling (England) rootstocks, or the Russian BUD rootstock series. This represents rootstocks selected at only 3 locations, optimized for 3 climates, 3 soil types, and common production challenges found in 3 regions.
While good efforts have been made to evaluate the adaptability of rootstocks beyond the original research stations where they were selected, additional screening usually takes place within regions where the apple industry is already well established (and where previous Geneva, Malling, and Russian rootstocks were already successful). This process does little to expand the range of rootstock options for new regions and new climates.
The result is that aspiring apple growers are often forced to artificially re-create optimal growing conditions for the rootstocks available to them. Irrigation systems, drain tile, even the placement of apple trees on elevated beds are just a few of the common ways farmers modify land to sustain non-locally adapted rootstocks.
We believe this approach is fundamentally flawed. Rather than altering land and water to meet the needs of a crop, an agro-ecological approach should call for planting crops that are already adapted to the local landscape and the local climate. This project was launched as with the intention of developing precisely such an option for the maritime Pacific Northwest.
Six species in the Malus genus are native to North America. In the western United States this includes Malus fusca (the Pacific crabapple), a species that is abundant in maritime climates extending from Alaska to Northern California. Unique among apple species, Malus fusca exhibits a wide-range of adaptability to common maritime site conditions: thriving in hydric and wetland soils (including saltwater estuaries), as well as in heavy clay soils, and poorly drained upland sites. It is considered a keystone native species in both high rainfall climates such as coastal mountain rainforests, and in lowland rainshadow environments such as the Puget Sound ‘banana belt’ where local rainfall averages may total less than 20 inches annually.
For at least two decades a handful of amateur pomologists and backyard orchardists in the Northwest have dabbled with the use of Malus fusca as a rootstock for table apple varieties. Anecdotally, these novelty grafts have been largely successful, apparently thriving even in conditions where traditional apple rootstocks do not, such as wet meadows. Unfortunately there is no actual research demonstrating how widely compatible Malus fusca is with various apple varieties.
Through this project we are establishing a replicated research block of Malus fusca rootstocks, testing more than two dozen apple varieties for grafting compatibility over a three-year period (with additional traits, such as suckering, evaluated in future years).
Continue to watch this page for more project details, updates, and extended information on the ecology of Malus fusca.
Orchard Block Site Preparation Begins
October 30, 2017
We’ve been working diligently at the farm to prep our research block planting area. The first step was some extensive brush hogging and mowing of an abandoned pasture area. In the weeks and months ahead we will be getting the deer fence installed, laying out the rows, and removing the existing vegetation (replacing it with a native grass/forb understory to support beneficial insects, pollinators, broader biodiversity).
Interestingly, there are several wild Malus fusca in the hedgerow around the planting area so we know the species is well adapted to the site. This removes one variable from the study, although we will maintain a control group of non-grafted Malus fusca trees in the orchard block which will allow us to compare the growth potential against the grafted trees.
Site Preparation Continues
December 20, 2017
Our BCS tractor has been putting in lots of hours prepping ground for the new orchard block. We don't have a huge range of implements but have been successful at prepping the site using an Italian-made R2 Rinaldi Stone Burying Plow. The tool is a reverse tiller (the blades spin in counter rotation to the tractor's direction of travel) with a fence of heavy gauge metal bars that separate rocks, vegetation, roots, thatch and other debris from the soil and pushes it all to the bottom of the plow pan -- leaving a smooth fluffy bed of soil that is rolled by the trailing packing wheel. It's definitely not a plow for ongoing use, but so far it has been good for breaking and prepping new ground.
We should note that we could just plant the new orchard block in the existing pasture vegetation except for a couple of things: The pasture is heavily invaded with wild rose, snowberry and other shrubs to the point that mowing alone wasn't giving us good control of the competing woody vegetation. We really needed a cleaner slate to give small transplanted apple trees a competitive edge. Second, we want to establish a higher quality/higher diversity understory for the orchard consisting of native grasses and native wildflowers such as camas. The aggressive non-native forage grasses dominating the pasture are a barrier to that goal. With the use of a native rootstock for the apple trees and a native seed mix for revegetating the understory, we hope to have a mostly native plant community with all of the associated benefits to soil health and soil biodiversity.
Scion Wood Selection
January 9, 2018
(Photo by Ed Scheenstra)
With gracious support from our technical advisor Dr. Carol Miles and her technician Ed Scheenstra at Washington State University's Northwest Research and Extension Center, we've been able to secure scion wood for the following varieties: Amere de Berthcourt, Blanc Mollet, De Bouteville, Brown Snout, Brown Thorn, Bulmer’s Norman, Cimetiere, Court Pendu Rose, Dabinett, Domaines, Frequin Rouge, Jouveaux, Medaille D’Or, Mettais, Michelin, Muscadet de Dieppe, Muscat de Bernay, Peau de Vache, Reine des Pommes, Vilberie, and Zabergau Reinette.
Additionally, we are expecting a second batch of scion varieties from Dr. Thomas Chao, the USDA's apple genetic resources horticulturist (sort of a librarian of apple varieties!). Those scion varieties include: Sangre de Toro, Raxao, Blanquina, Teorica, Xuanina, Vedialona, Coloradona, Solarina, De la Riega, Collaos, Perico, Maria Elena, Reineta do Caravia, Repinaldo do Liebana, Pepa, Peil de Sapa, Bedan des Parts, Manchurian, Wickson, Binet Rouge, Calville Blanc, Nehou, Dolgo, Kerry Pippin, and Irish Peach.
In the weeks ahead grafting will begin at a feverish pace when our shipment of 500 rootstocks arrive from the nursery. We are aiming to do 10 or 12 replicated grafts of most varieties, but in some cases limited scion availability will result in fewer grafts of some varieties.