Grapevines for the South

Distinction

• Muscadine grapes look different than supermarket grapes, which are also called bunch or table grapes. They grow in loose clusters instead of pendant bunches, with grapes ripening individually instead of collectively. Although muscadines grow in U.S. Department of Agriculture plant hardiness zones 7 and warmer, they are particularly adapted to the high heat and humidity found in the South. Muscadine grape skins are thicker than those of bunch grapes and are often discarded instead of eaten with the sweet pulp.

Water and Fertilizer

• Muscadines prosper when they receive 1 inch of rain weekly during their active growing season. This is generally the amount that wets the soil to a depth of 12 inches. If rain in any two-week period during the growing season does not supply this amount, muscadines must receive supplemental watering. During the first two years after planting, muscadine flowers should be removed so that vines become strongly established. Immediately after planting, 1 cup of 10-10-10 fertilizer applied in a 2-foot-diameter circle around each vine boosts healthy growth, followed by 2 ounces of ammonium nitrate applied in late May and again in early July. In the second year, growing vines respond to double the fertilizer applications at the same timing. Third-year growth responds to 2 pounds of 10-10-10 fertilizer per vine, applied in a 6-foot circle in March, and another duplicate application in May. Thereafter, established vines flourish when they are given 3 to 5 pounds of 10-10-10 each year in March, and 1/2 pound of ammonium nitrate in May.

Sun, Soil and Support

• Vines produce best when planted in full sun with rows laid out in a north-south orientation. Well-draining soil is essential to the health of muscadine roots, which may die if they become waterlogged. The optimal soil pH for muscadines is between 5.5 to 6.5. Muscadine grape vines are prolific, and they need support for optimal performance. Trellises can be constructed from a single- or double-wire system strung between sturdy, 5- to 6-foot-tall posts, with 4 feet of spacing between double wires.

Flowers and Fruit

• Muscadines produce more than four times the harvest as bunch grapes, typically yielding 35 pounds of fruit per vine instead of the 8 pounds per vine their European counterparts bear. For maximum yields, muscadines require successful pollination for abundant fruit set. Muscadine vines may be self-fruitful, which means that male and female flowers are borne on the same plant, or they may be pistillate plants, that bear only female flowers. If you plant pistillate vines, such as “Black Beauty” or “Scarlet,” they need a pollinizer planted nearby, such as “Carlos” or “Tara,” to ensure fruit set.

Pests and Diseases

• Because of their strong resistance to pests and diseases, muscadines are often grown organically or with minimal chemical intervention. Although muscadines do not prosper in Mediterranean climates, European grape vine scions are commonly grafted onto muscadine rootstocks to form a stronger plant that can better withstand pests and diseases. Pierce’s disease, phylloxera and nematodes plague other grape species, but muscadines are virtually immune to their ill effects. When there is a problem, a fungal pathogen is generally the culprit. To manage fungal diseases, such as bitter rot (Melanconium fuligineum) and angular leaf spot (Mycosphaerella angulata), the Mississippi State University Extension Service recommends using preventive fungicides.