Pruning Petunias

A Guide to Growing and Pruning Petunias

Petunias, like roses, are one of the most popular garden flowers in the world, but unlike roses, maintaining and pruning petunias is easy. People fall in love with petunias because they come in so many different varieties and colors. There are multifloras, grandifloras, floribundas, and millifloras. Not only do they come in every color under the rainbow, you can have single or double flowers and spreading varieties. Petunias are favorites because they blossom continuously from late spring until early fall.

Petunias are in the nightshade (Solanaceae) family, which includes such well-known vegetables as tomatoes and peppers. The flower has existed for centuries and was one of the first upon which modern plant genetics was used. Many advances took place at the turn of the 20th century, but the greatest leaps with hybrids occurred after World War II.

The most popular petunia in the world is the grandiflora, which has either single or double flowers. The doubled-flowered type has large, 3 to 4 inch blossoms. They all come in just about any color imaginable, whether they are solid, two-colored, striped, deeply veined or picotees, which can be edged or even striped in a contrasting color.

The multiflora petunia also has single and double flowers but has somewhat smaller blossoms than the grandiflora. The flowers can range anywhere from an inch and a half to three inches. They also come in every color and you can have contrasting colors and stripes. Spreading petunias are known as “wave petunias,” and are used for ground cover.

While you can propagate some species of trailing petunias with cuttings, wave petunias can only be grown from seed.

Wave petunias are newer and can only be purchased in either pink or magenta purple. They produce prolific flowers and you never have to be in the garden pruning petunias, because they naturally cover the stems with flowers. Another new petunia is the millifora. The “Fantasy” was the first of this type of hybrid, introduced in 1996. They are small, only growing to three-fourths the size of a regular petunia. They also have small flowers, which are at most an inch to an inch and a half across, but they produce so abundantly that the entire plant is bursting with color. They need no pruning at all.

When you plant petunias, find a spot where they will receive full sunlight, which means at least six hours of sun every day. If you live in the southern United States, where it is exceptionally hot, you might want a spot with partial shade in the afternoon. Petunias can grow in just about any soil type but light and well-drained is the best. You can start seeds inside two to three months before spring planting or for most varieties, seedlings will be available at local nurseries and gardening stores.

Petunia seeds are very small so try to spread them out as much as you can. Just plant in regular seed starter soil and make sure they are moist so that they germinate well. Plant outside after all danger of frost has passed. Most petunias can be planted ten inches apart but the spreading varieties can be as far apart as twenty inches. Most petunias grow to be a foot high but some, like floribundas, can grow to be sixteen inches tall.


Petunias are very easy to care for, needing some fertilizer applied around once a month throughout the growing season. They do not normally need any extra watering unless there is a prolonged period of drought conditions. Some petunias can look straggly in mid-summer but pruning petunias is easily done.

You can deadhead blooms when they are past for best flower production. You can also prune the petunia so that it will get bushier and grow new flowers along its stems. All you need to do is pinch off the new growth at the end of the stem, which is right in front of the flower. Sometimes it is hidden by the flower. Just look behind the flower, if this is the case. Milliflora and the trailing types of petunias need no pruning at all.

Whatever your preference for flower sizes and colors, you are sure to find just the right petunias to brighten your yard. Many gardeners use them to edge the yard or garden. They are also one of the flowers most frequently seen in window boxes. Try planting some petunias next growing season and you won’t be disappointed.