Grapes are among the few ornamental vines with bold, textured foliage; colorful, edible fruit; and a dominant trunk and branch pattern for winter interest. A single grapevine can produce enough new growth every year to arch over a walk, roof an arbor, form a leafy wall, or provide an umbrella of shade over a deck or terrace.
For good-quality fruit, choose a type that fits your climate, train it carefully, and prune it regularly.
There are several basic types of grapes. European grapes (Vitis vinifera) have tight skin, a high heat requirement, and cold tolerance to about 0F. These are the market table grapes, such as 'Thompson Seedless'. The classic wine grapes, such as 'Cabernet', 'Chardonnay', and 'Pinot Noir', are also European in origin. Production of European wine grapes is well established in Texas, Virginia, Maryland, Missouri, and North Carolina.
American grapes are derived from Vitis labrusca, with some influence from other American native species and also often from Vitis vinifera. These are slipskin grapes of the 'Concord' type, which have a moderate summer heat requirement and tolerate temperatures well below 0F. American grapes are used mainly for jelly, in unfermented grape juice, and as soft-drink flavoring; some wine, usually sweet, is also made from them. Most will not thrive in the Lower and Coastal South; there the grape of choice is the muscadine (V.rotundifolia), which bears large fruit in small clusters. Most muscadine selections are self-fertile, while others (females) require cross-pollination. (All other types of grapes are self-pollinating.)
Pierce's disease, caused by a bacterium spread by the sharpshooter insect, is lethal to European grapes and severely limits their cultivation in Florida and the Coastal South. They should not be planted south of a line that runs roughly from Raleigh, North Carolina, west through Atlanta, Birmingham, and Greenwood, Mississippi, to Shreveport, Louisiana, to Dallas-Fort Worth. In Texas, Pierce's disease affects only the state's southeastern corner. Most muscadine grapes and some American grapes resist Pierce's disease.
European and American grapes may also suffer from the fungal diseases black rot, which causes fruit to rot on the vine, and downy mildew, resulting in cottony white patches on the leaf undersides and shoot dieback. Control both by applying a fixed-copper fungicide. Muscadines can have problems with fruit rots but are less susceptible to a number of diseases affecting European and American grapes.
In some areas, a regular spraying program may be necessary to protect vines and fruit from insects and/or diseases.
Vines need regular applications of fertilizer to remain productive. Specific recommendations vary slightly among different parts of the South, so contact your Cooperative Extension Office to see whether additional nutrients are needed in your area. In general, however, you can begin fertilizing after the newly planted vines have been settled by a drenching rain. Before growth begins, apply 14 cup of 10-5-10 fertilizer around each plant, keeping the fertilizer at least 6 inches away from the vine. Repeat every six weeks until mid-July. Two-year-old vines need double that amount of fertilizer applied at the same six-week intervals and for the same duration. For mature vines, apply 212 pounds of 10-5-10 fertilizer per plant in March. If growth is poor, an additional pound of the same fertilizer can be applied in May.
Once established, grapevines grow rampantly. If all you want is a leafy cover for an arbor or a sitting area, you need only train a strong vine up and over its support and thin out tangled growth each year. But most people plant grapes for fruit, even if they want shade as well. For good fruit production, you will need to follow more careful pruning procedures (see illustrations on facing page).
Grapes are produced in late summer and fall on stems that develop from 1-year-old woodstems that formed the previous season. These stems have smooth bark; older ones have rough, shaggy bark. The purpose of pruning is to limit the amount of potential fruiting wood, ensuring that the plant doesn't produce too much fruit and that the fruit it does bear is of good quality.
The two most widely used methods are spur pruning and cane pruning; see chart for recommended pruning method for each selection. Either technique can be used for training grapes on arbors. Whichever method you choose, the initial stepsplanting and creating a frameworkare the same. Pruning should be done in winter or earliest spring, before the buds swell. (See facing page for planting details.)