Petunia x hybrida
Few annuals can equal the flower power of the Petunia. Whether you choose the mounding, spreading, or trailing varieties, Petunia is prepared to begin flowering with the first breath of summer and not to quit until the chill of late fall. Get your hanging baskets, window boxes, flowerpots, and sunny garden beds ready for an explosion of soft color that just won't quit!
There are literally hundreds of named petunia varieties. They fall into four distinct categories, based on flower size and growth habit. Some are more suited to container growing, while others are better for massing in the garden.
Grandiflora petunias, the most popular type, produce large flowers that are three to four or more inches across. They may be singles or ruffly doubles. Some have a pendulous, cascading habit that makes them more suitable for hanging baskets and window boxes, but most are upright plants that develop over the summer into large mounds of flowers which are twelve to fifteen inches tall.
Multiflora petunias are often more compact. Their flowers are smaller than the grandifloras, but they make up for it with the sheer number of blossoms that are open at any given time. Like grandiflora varieties, they're available in single or double forms, though the vast majority are singles. Typically, they're massed together to create big splashes of color in the garden.
Milliflora petunias are compact, miniature plants that produce abundant quantities of perfect, small flowers only an inch to an inch and a half in diameter. They make good edging plants and are also attractive when mixed with other flowering annuals in containers, where they may be viewed close-up.
Groundcover or "spreading" petunias are only about six inches tall, but spread so rapidly that they cover a huge area over one growing season, provided they're watered and fertilized frequently. This makes them ideal for scrambling down a hillside garden, or planting atop a retaining wall. They're also amazing in hanging baskets and window boxes, where they trail two to three feet or more over the summer. When grown in full sunlight, they are so covered by flowers that you hardly see any foliage.