Petunia Varieties

Choosing the right Petunia for you is mostly a matter of preference. The only class that isn’t suitable for almost any purpose is the Grandifloras, which do not tend to perform as well in some climates. There are five basic types of petunia, each with somewhat different flowers and growing habits.

Grandifloras are the largest petunias, with blooms as large as three or four inches across. They generally have an upright habit, though some tend more toward cascading. Because they have such large, tender blooms, Grandifloras are susceptible to damage and rot in hot, humid summers.

Multifloras have a more compact habit and smaller flowers than the Grandifloras, but they tend to be more durable and bloom more prolifically. They are available in both single- and double-flowered varieties.

Floribundas are somewhere between the Multifloras and the Grandifloras. They produce large amounts of medium-sized blooms.

Millifloras have the smallest blooms of the common Petunia types. These flowers are generally only about an inch to an inch and a half across. While small, the blooms are often prolific and long-lasting. Millifloras are very well-suited to low borders and smallish containers.

Ground Cover Petunias, also called Spreading or Trailing Petunias, are, as the name suggests, rather low-growing (often no higher than four to six inches). These are the newest class of Petunia (the Wave Petunias were the first cultivars available), and are quickly becoming more and more popular. Because the flowers form along the entire length of each stem, this class makes for excellent, very colorful ground covers. They also spread quickly and fill in densely. They have become the most commonly-seen Petunias in hanging baskets and window boxes in many areas, especially in the South, where Grandifloras don’t perform as well.

Growing Petunias

Petunias can be planted as soon as danger of frost is past in the spring. Plant in full sun for good flower shows. They grow well in most soils, but do best in well-drained soils of medium fertility. If overwatered or allowed to sit in water, foliage will yellow and the plant will eventually die. If over fertilized they will produce a weak show of flowers and an abundance of foliage. To encourage branching, pinch off about an inch from the top of the stem just before planting. In some varieties the plants will start to grow spindly and the flowering will stop about midway through the blooming season. Prune back to about half-length to encourage blooming again in this case. Water heavily every seven to ten days to encourage deep, healthy roots. Large or double flowers will need to be deadheaded to encourage new flowering.

Thomas Andrews is a garden writer for the Park Seed Company, proud carriers of the Wave Petunia. In a span of three generations, Park Seed Co. has grown from a one page list of seeds handed out to neighbors and friends to the largest family-owned direct-marketing horticulture company in the U.S. Park Seed offers gardeners, through its catalogs and corresponding web sites, thousands of choice seeds, plants, bulbs, and gardening aids.

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