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.

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Program Overview

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 emphasize 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.