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Cold Climate Grapes by Tom Plocher

Timeline and history of Tom's grape breeding work

1983-1996   Evaluation of breeding material
  • Cultivated and evaluated hardiness of over 100 interspecific hybrids, including French-American hybrids, and experimental  selections from Elmer Swenson, David Macgregor, and the University of Minnesota. 
  • Wine samples produced and evaluated for wine quality potential. 
  • Breeding strategy developed for hardy red wine grapes.

1996-1998  Controlled freezing tests
  • Bud and cane hardiness of promising cold hardy hybrids compared to local Vitis riparia. (Plocher and Rouse, 1998)
  • E.S. 10-18-06, MN 1094, and David Macgregor’s Riparia x St. Croix #5 identified as elite hardy cultivars.
  • Tests validated field observations of these selections during -40 degree winters of 1993-94, 1995-96, and 1996-97.

1996-2015  Controlled crosses, seedling evaluation
  • Seedling evaluation for hardiness and disease resistance
  • Produced and evaluated test samples of wine produced from promising seedlings.

1998  USDA sponsored evaluation of hardy, early ripening cultivars in The Baltics and Belarus.

2003-2005  USDA and PRC-sponsored evaluation of Chinese Vitis amurensis, and and large-clustered cultivars in Inner Mongolia, Jilin, and Heilongjiang.

2003-2005 Elmer Swenson Preservation Project evaluates dozens of advanced Swenson selections for use in breeding.

2009  T.P. 2-1-24 named and released as ‘Petite Pearl’.

2009  First selection for spring freeze resistance, T.P. 3-1-3-N, made after severe freeze of 17 May, 2009. 
  • T.P. 3-1-3-N was the only vine in the vineyard with surviving primary buds owing to its slow spring growth.
  • Slow spring growth derives from its pollen parent, Vitis palmata. Seed parent is E.S. 10-18-06.

2013  Petite Pearl and T.P. 1-1-12 certified virus-free by Foundation Plant Service, UC-Davis.

2015  T.P. 2-1-17 named and introduced as 'Crimson Pearl'.

2015  T.P. 1-1-34 named and introduced as 'Verona'.

2016  Crimson Pearl and Verona certified virus-free by Foundation Plant Service, UC-Davis

2017 First commercial wines produced from Crimson Pearl and Verona.

2017  Tom named Wisconsin wine industry person of the year.  Wisconsin has the largest planting of Petite Pearl vines in the US.

2019   New cold hardy selections identified after record cold in January, 2019.


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