Although there are thirty-five known Petunia species, most types of Petunia plant grown in the garden are hybrids.
Plants are annuals, and the genus is native to South America. As a member of the Solanaceae family it is closely related to food staples such as tomatoes, Aubergine, and peppers. Ornamental-wise, it is related to plants such as Browallia, Salpiglossis sinuate, and Physalis.
Petunia Surfinia by Joanna Papanikolaou.
Although, usually grown as hybrids some of the more known Petunia species include the Large White Petunia (Petunia axillaris, fragrant at night); the extremely rare red-flowered Petunia exserta; and Petunia integrifolia (purple flowered), which along with P. axillaris was used to create the first garden Petunia hybrid.
There are four major classifications of Petunia × hybrida: Hedgiflora (also includes the Petunia surfinia group); Grandiflora; Multiflora; and Milliflora. Cultivars can be single or double flowered.
Hedgiflora, and surfinia are low growing spreading plants, making them ideal for use as ground-cover.
Grandiflora have large flowers (4 inches (10 cm)), and a large array of colors.
Petunia Grandiflora supertunia by beautifulcataya.
Multiflora has flowers of about 2 inches (5 cm). These are more tolerant than Petunia Grandiflora, and not as susceptible to damage from heavy rains or bright sunlight. They are often grown as an hanging basket plant.
Petunia cv. Multiflora by Jim, the Photographer.
Milliflora / Floribunda have flowers of about 1 inch (2.5 cm). They can tolerate very bad weather, and make great container plants.
They are also ideal for use as edging and garden bed plants.
Petunia milliflora 'Shock Wave' by Scott Zona.
Due to the many different types of Petunia hybrida it is difficult to give an exact description of each plant. Therefore, what follows is a general guide with some information on specific cultivars.
Petunia plants range in height from 8 to 30 inches (20 to 75 cm) with spreads from 24 to 96 inches (60 to 240 cm).
Petunia hybrida by lezumbalaberenjena.
Hedgiflora Plants range in height from three to six inches (7.5 – 15 cm) with some varieties reaching above 20 inches (cv. Tidal Wave). The spread of Hedgiflora is usually in the range of 36 to 48 inches (90–120 cm).
Petunia surfinia are typically 5 to 7 inches (12.5 – 17.5 cm) in height with a spread of up to 96 inches (240 cm). Grandflora species range from 8 to 24 inches (20–60 cm) in height and spread to 36 inches (90 cm).
Leaves are simple, alternate, lanceolate to ovoid, and pale green. Stems are long and limp.
They bloom continuously from the end of spring, throughout summer, and for many cultivars until the first frost.
There are numerous flower colors available including red, white, pink, purple, blue, and yellow. Bi-colored forms are available.
Perfect flowers can be single or doubles, have five petals, are fragrant at night, and trumpet shaped. They have finger like green sepals.
I hope that you enjoyed this guide on Petunia hybrida plants. You may also enjoy the following Gardener's HQ growing guides: How to grow Fringe Flower and Apple of Peru plants.