LSU AgCenter Horticulturist
Grapes are one of the oldest and most extensively cultivated food crops in the world. The earliest archaeological evidence of the domesticated grape comes from an area between the Black Sea and Iran. Cultivated varieties were spread by humans through southern Greece to the Mediterranean region and on to Europe and the Americas.
Grapes are typically consumed as fresh fruit, dried as raisins and as wine. Every year, 7.2 trillion gallons of wine are produced worldwide, and 800,000 tons of raisins are produced using 3.2 million tons of grapes. Fresh grapes account for less than 12% of the world’s total grape production.
In the United States, the grape industry contributes about $125 billion dollars annually to the economy, and the average American eats about 8 pounds of grapes each year. Grapes are an excellent source of vitamins C and K, dietary fiber and minerals. In addition, grapes are high in a substance called resveratrol — a polyphenol that can provide powerful antioxidants, protecting the body against damage by free radicals associated with disease.
Grapes belong to the Vitaceae family, which contains 11 genera of 600 different species. The genus Vitus is the only food-bearing genus in the Vitaceae family and contains about 60 different species. Grapes are grouped into one of four different categories: European grapes (Vitis vinifera), French-American hybrids, native grapes and muscadine grapes (Vitis rotundifolia).
Native grapes were found in North America by the first European settlers and are prized for their cold hardiness and disease resistance. Muscadine grapes are what Louisianians are most familiar with, as they are native to the Gulf States and are profuse native growers here. Muscadines have a bold, musky flavor and large seeds.
Botanically speaking, grapes are berries. They can live up to hundreds of years, with the most productivity occurring in the first 50. The oldest grapevine in America, a 400-year-old muscadine vine, is in North Carolina. Grapes have the ability to tolerate a wide range of soils.
Muscadine grapes are the perfect grape of the South. Wild muscadines are dioecious with male and female flowers on separate vines, meaning you need a male and female vine to produce fruit for wild muscadines. However, there are self-fertile vines. Examples of self-fruitful muscadines (you only need to plant one vine of these for fruit) are Carlos, Cowart and Magnolia. Some other commonly carried grape varieties are Niagara, Mars and Concord.
Muscadines are predominantly dark skinned, growing in clusters of three to 10 berries. Fruit ripens in August and September. Up to 120 days is needed for fruit to mature, with some varieties ripening earlier than others. Improved muscadine varieties are available through local and online plant nurseries.
Muscadines are relatively disease free. When properly fertilized and managed, vines grow vigorously, so moderate insect and disease damage usually does not affect the plant.
Muscadine grapes are resistant to a devastating grape disease called Pierce’s disease. Most European-type grapes grown in southeastern U.S. inevitably succumb to this disease, and many times, the disease kills the vines before they can even make grapes. Muscadine grapes have a thicker, tougher skin than most table and wine grape cultivars.
If you want to plant your own muscadines, select a site with full sun or a minimum of six to eight hours of sun a day. The vines also will need well-drained, slightly acidic soils (5.5 to 6.5 pH) as well as a trellis for support. Muscadine plants can be purchased as bare-root plants; this is often how they come when bought from online sources. Bare-root plants are typically planted in January and February. These usually do not have foliage and will leaf out in the spring when the weather warms.
Local plant nurseries usually have recommended muscadine plants growing in 1- or 2-gallon containers with foliage on the vines. Vines grown in containers can be planted all through the growing season. Use a 15-to-20-foot spacing between vines to allow for horizontal vine growth on trellis. Single and double wire systems are very common and are placed 5 to 6 feet up from the ground.
Fertilize vines in the spring after growth starts with a complete fertilizer at a rate of 4 ounces the first year, 6 ounces the second and 1.5 pounds per vine the third year. Established vines should receive 2.5 to 4.5 pounds each year thereafter.
Annual pruning is required for optimal fruit production. Prune while dormant between mid-January and early March. Fruit forms on new growth from buds on the previous season’s growth. When pruning, keep a 6-inch spacing between the spurs along the cordon. The previous season’s growth will be pruned back, leaving a spur with two to four buds. New growth from these buds will be the fruiting wood. You will repeat this process of pruning back last season’s growth to spurs with two to four buds each year.
Muscadines ripening on the vine. Photo by Kiki Fontenot/LSU AgCenter
Table grapes produce more grapes per cluster than muscadines. Photo by Kiki Fontenot/LSU AgCenter
Muscadine planting with trellis at the Beaumont Horticulture Unit in Mississippi. Photo by Christine Coker/Mississippi State University