Wikipedia Article About Curly Parsley on Wikipedia Two forms of parsley are used as herbs: curly leaf and Italian or flat leaf. Curly leaf parsley is often used as a garnish. Many people think flat leaf parsley has a stronger flavor, and this opinion is backed by chemical analysis which finds much higher levels of essential oil in the flat-leaved cultivars. One of the compounds of the essential oil is apiol. Another type of parsley is grown as a root vegetable.