There are several species, with various hybrids and cultivars. It is native plant of South America. Dwarf or trailing varieties are best for growing in pots, such as petunia Surfinia, now commonly called just Surfinia, which is often grown in hanging baskets. They are grown somewhere sunny or semi shaded, to enjoy at least a few hours of direct sun to encourage flowering. From May until the autumn chills, in fact, they are covered with many trumpet-shaped flowers, of various sizes and colours. The typical colour of petunia is pink or blue, but you can find them in all shades of pink and purple, and also in shades of yellow and green, including striped or spotted varieties.
They prefer soft and fresh, fairly rich, and certainly very well-drained soil, where there is no danger of stagnant water. Avoid placing them in containers that are too small, so you can provide a good amount of water, because in the summer heat these plants need watering that is regular, abundant, and quite close. Every 12-15 days throughout the growing season add fertilizer for flowering plants to the irrigating water.
Periodically remove the faded flowers, and foliage or branches that may have been broken by bad weather or wind. Check that they have not been attacked by aphids, which often lurk among the leaves.