Region Description: Upper South
Major Cities: Charleston WV, Charlottesville VA, Cincinnati OH, Evansville IN, Fayetteville AR, Huntington WV, Lexington KY, Louisville KY, Oklahoma City OK, Paducah KY, Tulsa OK
The Upper South stretches from the western half of Maryland to Oklahoma. It includes West Virginia, the Appalachian region of western Virginia, then westward down the Ohio River, including all of Kentucky, Cincinnati, Ohio, the lower quarter of Indiana, a strip along the northern edge of Arkansas, and the southern edge of Missouri, and across the northern half of Oklahoma.
This regional typically has four distinct seasons, with most of the area in zone 6, (minimum of -10F), with occasionally lower temperatures. Rain and snowfall tends to be evenly distributed throughout the seasons, with an average of 40 to 45 inches in most of the region. Oklahoma is slightly drier, and the mountain areas in West Virginia, Virginia, and Kentucky receive slightly more moisture. Spring can start in March, with hot weather coming by June. Autumn stretches into November, with vivid colors on the deciduous trees. Much of winter moisture comes as rain rather than snow, with only the occasional severe snowstorm.
The Growing Season
Most of the area has a last spring frost date sometime during April, except for the cooler mountain areas, which can get frost up to one month later. For all but the higher elevations in West Virginia, which can get frost sometime during September, the average first autumn frost is sometime during October. This gives most gardeners a growing season between 180 and 210 days. Summers throughout the region are hot and humid. The average number of days per year above 86F range from 90 to 120 in Oklahoma to 60 to 90 in southern Indiana and central to western Kentucky. Mountainous areas progressively get cooler with higher altitudes, ranging from 60 days down to only 7 days a year above 86F. Temperate trees, shrubs and perennials thrive in this warm, yet moderate climate.