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WSU Cold Hardiness Data In Blueberries

Volume 10 Issue 2

February 12, 2021

For several years, the WA Blueberry Commission has funded WSU research to collect bud hardiness data and create a model. Our research team is still in the process of developing the model but we do collect, freeze, and cut buds to assess mortality of individ-ual flower initials. Below is the data for lethal temperatures. Important considerations when looking at the numbers are:

Date assessed and stage: If your buds have progressed in development since our date of assessment, the buds will be less cold hardy.
Location: Preceding and local temperatures are influential in the level of cold hardiness. Warmer sites will likely be less cold hardy with possibly more advanced buds.LT10oF: This is the Lethal Temperature in which 10% of the floral initials will die. This can vary by cultivar, site, temperatures, and stage.

Date assessed Location Cultivar Stage LT10oF
2-Feb-21 Whatcom Co. Aurora dormant -5
2-Feb-21 Whatcom Co. Draper dormant 3
2-Feb-21 Skagit Co. Aurora dormant -2
2-Feb-21 Skagit Co. Draper dormant 7
8-Feb-21 Prosser Aurora dormant and early bud swell -2
8-Feb-21 Prosser Draper dormant and early bud swell -0.4
8-Feb-21 Prosser Duke dormant and early bud swell -4
8-Feb-21 Paterson Aurora dormant and early bud swell -2
8-Feb-21 Paterson Draper dormant and early bud swell -4
4-Feb-21 North Prosser Aurora dormant and early bud swell -9
4-Feb-21 North Prosser Draper dormant and early bud swell -2
Please note that in all prior years of studying cold hardiness, we have seen buds at bud swell reacclimate to cold weather within 24 hours. The 3 cultivars here are all highbush blueberries. Other cultivars with more southern highbush in the germplasm (e.g. Legacy) will have lower hardiness.

 

For more information:
AgWeatherNet (http://weather.wsu.edu/) has grape and cherry cold hardiness models. Log on and go to crop models.
Blueberry concerns:
Eastern WA, Gwen Hoheisel (ghoheisel@wsu.edu) Western WA, Lisa DeVetter, Lisa Wasko (lisa.devetter@wsu.edu)
Michigan Cold Hardiness Bud Chart (https://www.canr.msu.edu/blueberries/growing_blueberries/growth-stages)

This work was funded by the Washington Blueberry Commission