“Marketable nut and kernel yield of ‘Yamhill’ exceeded ‘Barcelona’ in all years of testing.” –Oregon State University extension publication
About the nuts: Huge Yields Yamhill is a heavy yielding cultivar producing small, round kernels well-suited for the blanched kernel market. Its small kernels are an ideal product for the chocolate and baking industries. Kernels are attractive, of high-quality and overall show very few defects. Yamhill also boasts a very high shell-out rate of 49%. Like Dorris, Yamhill is a much smaller tree than most of the other cultivars planted in the Northwest. However, its small size doesn’t compute to small yields. In fact, cumulative marketable nut yield per tree exceeded Barcelona in every year even though the trees are 30% shorter and 50-60% smaller in cross-sectional area. Overall, Yamhill is a very efficient producer.
Mature Yamhill Hazelnut Tree at the OSU test plots in Corvallis
About the Tree
Yamhill is the most compact of all the widely planted varieties. However, due to the tree’s spreading habit, its canopy is only 12% smaller than Barcelona. The shape of the canopy allows for very good light penetration. The smaller size of the tree might offer growers the opportunity to plant Yamhill trees closer together and further increase their per acre tonnage. Although the smaller Yamhill trees be less vigorous than other cultivars, once established their yields surpass most other cultivars, according to both growers and researchers. Yamhill’s lower level branches have caused issues with harvesting and general tree care. To remedy this situation, we choose the most upright scaffold branches we can to encourage more upward growth.
Pollination, Bloom Time and Harvest
Yamhill female flowers bloom very early with both Sacajawea and Wepster. Alleles 8 and 26 are expressed in the flowers. Oregon State reccomends the following for pollinizers: Sacajawea (25%), York (50%), Gamma (25%). Dorris, Wepster and Jefferson are also suitable pollinizers for Yamhill. As a pollinizer, Yamhill is almost too short to be a viable option. It expresses allele 8 in its pollen. Yamhill has an early harvest, typically 10-15 days before Barcelona. Since early nuts are often paid a premium by processors, Yamhill’s early timing should make it an even more attractive option for growers.