Best growth is obtained on well-drained, fertile soils and under a high relative humidity. The species are cold sensitive but tolerant of drought. The essential oil accumulates in small glands found in the foliage and flowers. Harvesting, usually done by hand two or three times annually, begins as the plant starts flowering. The herb is cut in the morning in sunny, dry weather.
Distillation begins after a few hours of field drying.
There are several types of geranium oil, the main ones being Reunion or Bourbon, Algerian, Moroccan, and French. Reunion oil is very rich in citronellol and has a heavy rose and minty odor. Algerian oil has a delicate odor. Moroccan oil is similar to Algerian oil. French oil is thought to possess the finest rose-like odor.