Each of the following eight types of oregano has its own distinctive flavor, from intensely spicy to subtle and sweet. Remember that anything labeled simply "Origanum vulgare" will most likely rate a culinary zero.
Cretan (O. onites). Tender perennial growing to 18 inches tall, with pale green to gray-green woolly rounded foliage. Also sold as pot marjoram or Turkish oregano. Strong, intensely spicy flavor. USDA Plant Hardiness Zone 8
Golden (O. vulgare 'Aureum'). Golden foliage adds pizzazz in the garden as well as the kitchen. Grows from 6 to 18 inches tall. Will tolerate shade, but leaves will be more chartreuse than golden if it's placed there. Mild oregano flavor. Zone 6
Greek (O. vulgare subsp. hirtum). Vigorous and very hardy. Grows to 3 feet tall with green, slightly hairy foliage. Greek oregano is generally best for most culinary uses, with 'Kaliteri' (a strain within the species) delivering the truest of oregano flavor (see below). Zone 5
'Hot & Spicy' (O. vulgare 'Hot & Spicy'). A potent cultivar of Greek oregano growing to 3 feet in height. As its name states, this one is hot and spicy. Zone 5
Italian (O. 5 majoricum). Also sold as Sicilian oregano or hardy sweet marjoram. Italian oregano is an exquisite blend of sweet and spicy, without the bitterness of more intense types. That characteristic flavor varies, however, as Italian oregano is a hybrid resulting from crossing sweet marjoram with oregano. Plant form, leaf size, and color can vary depending on the parents, but most plants are upright in growth to 2 feet tall, with small pale green to gray-green leaves. Wonderful fragrance and gourmet flavor. Zone 7
'Kaliteri' (O. vulgare 'Kaliteri'). This Greek strain is truly among the best (kaliteri means "the best" in Greek). Grows to 18 inches tall with silvery gray foliage. Spicy and flavorful without being too bitter. Zones 6 & 7
Khirgizstan (O. vulgare subsp. gracile, syn. O. tyttanthum). More ornamental than other types, with glossy green leaves and pink flowers. Bushy growth to 18 inches tall. Pungently spicy with true oregano flavor. Excellent container variety, with stems that spill over the edge. Zones 5 & 6
Syrian (O. syriacum; O. maru). Tender perennial, sometimes sold as Lebanese oregano. Variable in foliage color from pale green to gray, with larger leaves than Greek or Italian types. Grows 18 inches to 3 feet tall. Pungent oregano flavor similar to that of Greek. Zone 8
That spicy, robust oregano taste that's so synonymous with French and Italian cuisine doesn't come from just any plant labeled "oregano." This Mediterranean native belongs to the genus Origanum, which also includes sweet marjoram. But not all plants belonging to the Origanum family taste like oregano. Nurseries and garden centers often mistakenly sell a type of wild marjoram (Origanum vulgare) that has none of the spunk we expect from culinary oregano.