Take a drive around Columbia County, and it seems like everyone has some type of fruiting tree or vine growing in their landscape. One of more neglected fruit-bearing plants in the area is the muscadine. Muscadines are grapes native to America, and they are a staple of home gardens all over the Southeast.
Following a few simple steps will greatly increase the health of your vines and produce bigger, sweeter grapes.
In Columbia County, muscadines should be pruned from February to early March. Don’t be alarmed if the vines start to bleed sap from the pruning cuts, especially if you prune closer to spring. This is normal in actively-growing grape vines.
Muscadines come from new shoots on last year’s growth. Severely pruning vines back to the main vine or pruning late in the growing season can hinder fruit production the following year. When pruning muscadine vines, look carefully for new wood. It is usually light brown and softer in appearance than tough-looking old wood.
Starting at the base of the new wood canes, identify three to four buds and make the pruning cut with bypass shears just above these selected buds. A good rule of thumb for fast pruning is to leave 3 inches of new wood; this will usually keep three or four buds on the cane. New shoots will arise from these selected buds. By limiting the number of buds, the muscadines from these shoots will be of superior quality.
After a few years of selective pruning, the vines will develop small masses of old wood called “fruiting spurs.” These spurs are a good reference point for selecting buds for fruiting. The fruiting spurs should be spaced out every 6 inches or so along the vines. While pruning, make sure to take off any dying or diseased canes.
If the vines have grown for several years without pruning, there may be tendrils, which are shoots the muscadine uses for attaching itself to structures. Tendrils must be pruned because they can strangle other shoots. After three or four years of production, remove every other spur cluster to prevent overcrowding. Try to leave spurs that are on the top of the arms. It is also a good idea to remove the oldest fruit stems because they can be a source of disease.
Muscadine vines that have been neglected for many years often can be rejuvenated. Prune back the old wood to the main vines on the trellis and start forming new fruiting spurs. A severe pruning will result in very little fruit the year of the pruning.
Another major requirement to ensure proper fruit production is fertilization. On new muscadine vines, apply fertilizer three times during the year. The first application is a half-pound of 10-10-10 after planting. The second application is 2 ounces of ammonium nitrate in late May, and the third application is 2 ounces of ammonium nitrate in early July.
Broadcast each application over a 2-foot circle centered over the rootball of the muscadine vine.
During the second year of establishment, the timing and method of fertilization remain the same. However, the rate for each application is doubled and the diameter of the broadcast circle is increased to 4 feet. During the third year, if the vine has grown well and has been properly pruned, a crop can be expected. Apply 2 pounds of 10-10-10 or equivalent per vine in March. In May, apply 1 pound of 10-10-10 per vine. These should be broadcast in a 6-foot circle around the rootball. For established vines, apply 3 to 5 pounds of 10-10-10 per plant in March of each year. Then apply a half-pound of ammonium nitrate around June 1.
As always, soil samples are needed before planting, and it is a good idea to check the soil pH every three years.