As the olive is a Mediterranean native, watering should mirror those climatic conditions. Summer irrigation should be deep and infrequent, becoming more substantial during the winter months. Olive trees will tolerate lawn conditions, but care should be taken to mound the soil at the time of planting in order to shed excess water from the base of the tree. Overwatering may create conditions that invite root disorders. Few pests or diseases plagued the European olive, although occasional problems with olive knot, verticillium wilt, root rot and olive scale may occur.
More frequent problems occur with trees located in areas which experience cold winters.
Extreme cold may cause damage which may predispose trees to disease. Damage may occur when temperatures dip below 15 Fahrenheit and crop damage below 28F. Young trees grow rapidly, but growth slows as they mature, eventually reaching a height of 25 to 30 feet, depending on the cultivar. Most trees naturally develop a multi-trunk growth habit. Single trunk trees require considerable training, involving judicious pruning and staking to control the natural habit. Highly revered for fruit production within the U.S., the olive is primarily grown in Europe for extracting the oil, although Spain exports large quantities of olives.