Compound bud, showing the leaf scar from the previous season. The bud scales encapsulate the primary and secondary bud that already have the preformed shoots and floral organs that were developed in summer 2015. -Photo by John Thull

 

Compound bud has been cut open to reveal the two whorls of primary and secondary buds. In this case both of the buds have survived. Notice green tissues. -Photo by John Thull

Damaged primary bud but surviving secondary buds. Notice no green tissue remains that would become the shoot in 2016. -Photo by John Thull

On 2/19/2016, buds were chopped for winter survival measurements on 7 sentinel varieties at the University of Minnesota research vineyards at the Horticultural Research Center.  The data represented here are just an example using a small sample number of canes, buds, and cultivars.  Only 4 canes, 8 buds each were evaluated (32 total buds).  We urge you to begin sampling your own vineyards as there is some evidence of damage. At this point, no changes would be needed to pruning based on these results at this location.  More complete data will be presented in coming weeks.

Cultivar    Primary Bud Survival

Brianna 94%

Frontenac 84%

Frontenac gris 97%

Frontenac blanc 84%

La Crescent 91%

Marquette 88%

St. Croix 91%