Nellie R. Stevens holly is a cultivar of the Ilex species noted for its unusually high tolerance among hollies for warm weather and humid conditions, according to Texas A & M University. The tree reaches up to 40 feet in height and matures into a wide, roughly pyramid form. It is hardy in USDA zones 6a through 9b and somewhat drought tolerant when well established. Like all hollies, it prefers moist, acidic soil but cannot tolerate pooling water around the roots. Wilt most commonly stems from cultural imbalances that should be corrected first, with other possibilities pursued if the cultural corrections don't work.
Examine the soil around your wilted holly. Feel the surface of the soil and again at 6 to 12 inches down. If the soil is very wet, over-irrigation or poor drainage may be the problem causing the roots to suffocate and even rot. Refrain from watering until the soil dries out to just barely moist. If the soil is dry, the holly is suffering from drought and the soil should be drenched to a depth of 12 inches immediately to revive the plant.
Prune away surrounding trees that may be preventing your holly from getting enough sunlight. While the plants can tolerate partial shade, they prefer direct sun. Deep shade caused by upper canopy trees or structures can weaken the plant and may play into the stress the shrub is experiencing.
Fertilize your wilted holly with an organic, acid-rich fertilizer with a guaranteed analysis of 4-6-4, such as Holly-Tone. Apply according to label dosing directions all around the root zone to out past the drip line. Water in well, until the soil is drenched to a depth of 6 inches down. Don't apply high-nitrogen, fast-acting chemical fertilizers, as these can add to the stress on the holly plant.
Gather a sample of the growing soil to have it tested for nutrient deficiencies, pH level, fungal disease, insect activity, contamination or other pathogens. Test results can dictate further specific steps to take to improve the holly's growing conditions and address disease, if possible.