grapes in a vineyard

Research Importance

MSU WARC is conducting research in cold-hardy grapes that are adapted to favorable sites in Montana to support the growing vineyard and winery industry in the state. There are currently 53 vineyards planted in Montana, with over 25,000 vines. WARC, in partnership with the Montana Wine and Grape Association, is studying pruning, control of canopy vigor, vine nutrition and irrigation practices in vineyards throughout the state, to help growers determine how these practices affect fruit chemistries (sugars and acids) for the optimal fruit quality and wine flavor.


The cold-hardy wine grape varieties that are grown in Montana and other USDA plant hardiness zone 4-6 areas are French-American hybrid grapevines, created by crossing French wine grapes (Vitis vinifera) that are only hardy to -5⁰ F with American native grapes, most commonly Vitis aestivalis (the Summer grape); Vitis riparia (the Riverbank grape), and Vitis rupestris, (the Sand grape). Breeding programs continue to improve hybrid grapevines, with active programs at Cornell University, the University of Minnesota and North Dakota State University that have created thousands of new varieties. In addition to cold tolerance, French-American hybrids are more resistant to common vineyard diseases like downy and powdery mildew, nematodes and phylloxera. French-American hybrids can produce quality wines when there’s sufficient heat during the growing season to ripen the grapes (~2000 growing degree days base 50⁰ F). Site selection is critical to ensure good ripening conditions and the most favorable areas in Montana include the Yellowstone River and Clark Fork of the Yellowstone valleys and warmer sites west of the continental divide.

Research Summary


MSU WARC current research vineyard was planted in 2014, with an additional planting in 2016. The varietals chosen at WARC are Marquette, Frontenac, Petite Pearl, Frontenac Gris, LaCrescent, and St.Pepin as wine grapes, with Somerset Seedless and Bluebell for table grapes. The 2016 planting included Crimson Pearl, Verona, Baltica, and three yet unnamed Tom Plocher varietals, TP B-3-40, TP 1-1-12 and TP 2-3-51 (http://www.petitepearlplus.com/). These vines are studied for their cold hardiness and winter survival rates, as well as their phenology, to monitor bud burst, fruit set, and harvest in this area of the state.


Results

The most popular red wine varieties currently planted in Montana include Marquette, Petite Pearl, Marechal Foch, and Frontenac, while the most widely planted white variety is St. Pepin, followed by Prairie Star. Some of the many other cold hardy varietals include Frontenac Gris, Crimson Pearl, St.Croix, Verona, LaCrescent, Leon Millot, Louise Swenson, Itasca, and Sabrevois. In our research vineyard, all varieties planted in 2014 have grown well. Among the red wine varieties, Frontenac has larger clusters (Table 1) and is very vigorous and productive (Table 2). Marquette has experienced higher mortality (Table 2, as seen in other vineyards in the state), but produces quality juice. Petite Pearl has lower sugar content and lower total acidity (TA, Table 2).

Our results also emphsize the balance between production and quality in grapes. In 2018, an average of 128 clusters per vine were left to ripen (more than twice the number compared to the year before). The increase in production was associated with a large increase in total acidity (Tables 2 and 3).

Table 1. Cluster and berry weights for grape varieties in trials planted in 2014 at WARC
Type Variety Cluster Wt (g) Berry Wt (g)

 

 

Red

Frontenac

70.8

0.9

Marquette 44.6 0.9
Petite Pearl 44.7 0.9

 

Table

Bluebell 64.4 2.5
Table/White Somerset Seedless 25 0.9

 

White

Frontenac Gris 73.3 0.9
LaCrescent 52.9 1
St. Pepin 66.3 1.8
Table 2. Performance of three cold-hardy, red wine grape varieties planted in 2014 over 3 years at WARC.
Variety Year % Fruiting Harvest Date Clusters per vine Yield (lbs/plant) Yield (lbs/acre) Brix pH TA
Frontenac 2016

83

9/27

5 0.4 285 30.7 3.0 2.4
2017

100

9/21

50 9.2 5995 23.8 3.0 1.9
2018 100 10/3 149 19.3 12645 18.0 2.9 3.6
Marquette 2016 50 9/27 7 0.4 287 29.0 3.1 1.8
2017 67 9/21 63 6.3 4157 23.7 3.0 1.7
2018 67 10/3 126 12.1 7939 22.5 3.0 2.6
Petite Pearl 2016 92 9/27 7 0.6 384 21.9 3.1 1.3
2017 92 9/29 72 7.6 4961 19.1 3.1 1.0
2018 92 10/3 123 11.2 7368 17.0 3.0 2.4

 

All white wine varieties have been hardy and productive (Table 3). La Crescent and St. Pepin have had lower total acidity than Frontenac Gris when production is lower than 10 lbs/vine.

Table 3. Performance of three cold-hardy, white wine grape varieties planted in 2014 over 3 years at WARC.
Variety Year % Fruiting Harvest Date Clusters per Vine Yield (lbs/plant) Yield (lbs/acre) Brix pH TA

Frontenac Gris



2016

67

9/27

3 0.3 185 29.9 3.0 2.3
2017 75 9/21 41 7.3 4784 25.5 3.0 2.0
2018 83 10/3 124 17.8 11658 18.4 3.0 3.2
La Crescent 2016 75 9/27 5 0.4 291 25.4 3.0 2.3
2017 100 9/29 63 9.0 5867 24.4 3.0 1.8
2018 100 10/3 143 13.0 8530 21.7 3.0 3.0
St. Pepin 2016 58 9/27 2 0.2 101 23.7 3.1 1.2
2017 83 9/29 51 7.3 4812 21.3 3.1 1.2
2018 83 10/3 103 15.2 9981 18.1 3.1 2.4

 

Both table grape varieties have grown well, although Bluebell experienced higher mortality rates in the first few years. Both are productive and have excellent flavor. Bluebell has large purple grapes (Table 1) with a Concord grape flavor. Somerset seedless has small, peach colored grapes with a flavor reminiscent of peach and raspberry that ripen 3 to 4 weeks before Bluebell (Table 4).

Table 4. Performance of two cold-hardy, table grape varieties planted in 2014 over 3 years at WARC.
Variety Year % Fruiting Harvest Date Clusters per Vine Yield (lbs/plant) Yield (lbs/acre) Brix pH TA

Bluebell



2016

50

9/19

2 0.2 142 22.1 ND ND
2017 50 9/21 44 6.7 4381 21.3 3.1 0.9
2018 86 10/3 76 10 6531 16.7 3.1 2.3
Somerset Seedless 2016 50 9/19 4 0.2 139 25.6 ND ND
2017 100 9/6 42 4.0 2651 23.3 3.2 1.0
2018 100 9/9 161 9.0 5870 22.9 3.4 1.5

Conclusions

Quality table and wine grapes can be grown in warmer sites in Montana. MSU-WARC will continue to work with growers and winemakers to exploit the agro-tourism opportunities in the state.

Additional Grower Resources

Northern Grapes project: a collaboration of multiple universities to support grape growing and wine making in colder regions of the U.S.

Montana Grape and Winery Association

University of Minnesota Grape Program

An Iowa State University review of cold climate grape cultivars.

Minnesota Grape Growers Association-information on hardy wine and table grapes.

University of Wisconsin-Grape growing guide.

North Dakota State University Grape growing guide.