Rose in greenhouses, and in warmer countries they may also be grown under cover in order to ensure that the flowers are not damaged by weather and that pest and disease control can be carried out effectively. Significant quantities are grown in some tropical countries, and these are shipped by air to markets across the world. Some kind of roses are artificially coloured using dyed water, like rainbow roses. Rose perfumes are made from rose oil (also called attar of roses), which is a mixture of volatile essential oils obtained by steam distilling the crushed petals of roses. An associated product
Bergamot essential oil and furanocoumarins. The main compounds in the oil are limonene, linalyl acetate, linalool, γ-terpinene and β-pinene, and in smaller quantities geranial and β-bisabolene. The main non-volatile compounds are coumarins (citropten, 5-geranyloxy-7-methoxycoumarin) and furanocoumarins (bergapten, bergamottin). The bergamot essential oil is particularly subject to adulteration being an essential oil produced in relatively small quantities. Generally adulteration is to "cut" the oil, i.e. adding distilled essences of poor quality and low cost, for example of bitter orange and bergamot mint and/or mixtures of terpenes, natural or synthetic, or "reconstruct" the essence from synthetic chemicals, coloring it with chlorophyll. Worldwide, each year, around