Petunia is a genus of 20 species of flowering plants of South American origin. The popular flower of the same name derived its epithet from the French, which took the word pétun, 'tobacco', from a Tupi–Guarani language. A tender perennial plant, most of the varieties seen in gardens are hybrids (Petunia × atkinsiana, also known as Petunia × hybrida).
Taxonomy
Petunia is a genus in the family Solanaceae, subfamily Petunioideae. Well known members of Solanaceae in other subfamilies include tobacco (subfamily Nicotianoideae), and the cape gooseberry, tomato, potato, deadly nightshade and peppers (subfamily Solanoideae). Some botanists place the plants of the genus Calibrachoa in the genus Petunia, but this is not accepted by others. Petchoa is a hybrid genus derived from crossing Calibrachoa and Petunia.
Petunias are generally insect pollinated, with the exception of P. exserta, which is a rare, red-flowered, hummingbird-pollinated species. Most petunias are diploid with 14 chromosomes and are interfertile with other petunia species, as well as with Calibrachoa.
The tubular flowers are favoured by some Lepidoptera species, including the Hummingbird hawk moth.
Cultivation
Petunias can tolerate relatively harsh conditions and hot climates, but not frost. They need at least five hours of sunlight every day and flourish in moist soil and conditions of low atmospheric humidity. They are best grown from seed. Watering once a week should be sufficient in most regions. Hanging baskets and other containers need more frequent watering. Maximum growth occurs in late...
