Petunias for Brilliant Color All Summer Long

Petunias are a gorgeous tender perennial that keeps giving you blooms throughout the summer.

These flowers look amazing as part of container gardens on your patio, hanging baskets on your front porch, or the splash of quick color that your garden needs.

According to the University of Minnesota Extension, petunias are among the most popular flowering annual for their gorgeous color and sweet fragrance. Plus, they are easy for anyone to grow and available in multiple colors and varieties.

What are Petunias?

Petunias front door plants to decorate withView in gallery

Petunias are a tender perennial with 20 different species and a native of South America. Petunias survive in harsh sunny climates, but will not tolerate frost.

In most climates in North America, Petunias are grown as an annual because of their delicate nature.

What Does a Petunia Look Like?

The foliage of petunias is green with small leaves. It can trail or mound depending on the variety. The petunia flower resembles a wavy-edged trumpet. There are petunia flowers that are colors ranging from red, white, purple, yellow, pink, blue, and even black. They are solid and variegated varieties that are striped, speckled, and ombre.

Botanical namePetunia spp.
Light6-8 hours of sunlight per day for the most blooms, though will tolerate partial shade
WaterKeep well-watered, but not soggy
FertilizerFertilize once a month to every 2 weeks throughout the growing season from spring to the autumn
PestsMites, aphids, thrips, caterpillars, budworms, leafminers, snails, slugs
DiseasesPowdery mildew, gray mold
SoilWell-draining acidic soil
Climate ZonesHardy in Zones 10-11
Size6-24 inches tall, 3 feet wide
FoliageGreen foliage with a trailing habitat
ToxicityNon-toxic for humans and animals
FlowersBright colored flowers with solid and variegated patterns

Petunia Varieties

There are four types of petunias which are determined by their size and growth pattern.

  1. Grandiflora – These are the oldest variety of petunias. These plants have large and showy flowers with upright and cascading growth patterns. Deadhead these plants to encourage more blooms. They do not stand up well to heavy rains.
  2. Multiflora – These are smaller plants with more compact growth. These plants self-clean better, so not as much deadheading is required. These petunia flowers stand up better to rain.
  3. Milliflora – These are a small growing petunia plant that has a myriad of small blossoms. These are good for compact gardens and small containers.
  4. Trailing or Ground covers – These petunia plants have a growth habit that spreads or cascades depending on whether you plant them in the ground or in a container.

Petunias Care Guide

Grown as annuals, tender perennial petunias grow best in areas with sunny and warm conditions. You can keep the blooms coming by maintaining their care throughout the summer.


Petunias Sun or Shade?

Petunias thrive in long hours of bright sunlight. They will bloom best with 6-8 hours of sunlight. Petunias will grow in partial shade, but they will not have prolific flowers.


Water

Along with bright sunlight, petunias need ample water to thrive. These flowers have a shallow root system that cannot reach into the deeper ground for water. Water when the soil gets dry. You may need to water more often during the hot summer months. This is even more true in containers or hanging baskets where petunias will not have access to moisture in the ground. The spreading varieties of petunias require the most water.


Soil Conditions

Petunias love water, but they need the soil to drain the water away from their roots in order to avoid common petunia diseases like root rot. Choose a well-draining soil that is on the acidic side with a pH of 6-7. If you begin with heavy soil, blend in some compost to lighten it.


Weather Conditions for Petunias

As South American natives, petunias need warm weather to thrive. Plant them outdoors after the danger of frost has passed. They will grow best in temperatures from 55 degrees Fahrenheit to 80 degrees Fahrenheit. After the summer, you can prolong the flowers by covering them during periods of frost.


Fertilizer

Petunias need fertilizer all season long to keep producing their magnificent flowers. Either fertilize once every month to every two weeks with an all-purpose fertilizer, or apply a slow release fertilizer to the soil when you plant the petunias. If petunias are in containers you will need to fertilize more often than if petunias are in the ground. Make sure to water when you apply the fertilizer as the harsh chemicals can burn the delicate roots and allow the plant to absorb the nutrients.


Petunias Pests and Diseases

According to the University of California’s Integrated Pest Management Program, the most common petunia pests are mites, caterpillars, thrips, and leafminers. Inspect the plant to see if they are falling prey to these pests. Use insecticidal soaps and neem oil for mites, prune to get rid of leafminers and thrips, and pick off caterpillars that you see.

To avoid diseases like mildew and mold, keep the air circulation around plants good by spreading plants out. Make sure that the soil is well-draining to avoid root rot.


Petunia Spacings

In order to avoid some of the common diseases for petunias, make sure your plants are spaced out to ensure air circulation.

  • Grandiflora – Space these large plants at least 12 inches apart in a sunny location. Decrease this by a few inches if you plant your petunias in partial shade.
  • Small varieties like multifloras and millifloras – Plant these about 4-6 inches apart.
  • Trailing Petunias – Space these petunia plants at least 18 inches apart to give ample room for growth.
  • Container Petunias – Plant petunias in containers closer together to achieve the most effective look.

Propagation

Most gardeners will buy petunia plants from local nurseries, but petunias can also be grown from seed. This is not an easy proposition for a new gardener, but you will have more varieties available from seed than from plants.

You can also propagate new petunia plants with cutting from your current plants. This is an inexpensive way to increase your plants from just one parent plant.


Pruning and Maintenance

Grandiflora petunias require the most maintenance as their gorgeous blossoms are more delicate than other varieties. Pinch off any spent blossoms to encourage more growth. Other petunia varieties like multiflora and floribundas are self-cleaning and do not require as much deadheading.

If your petunias become leggy, pinch off the stems to encourage bushier growth. You may also notice other problems like yellowing leaves. This means that your plants are suffering from too much water on the roots as a result of poor-draining soil. Water the plants less often.

Companion Plants for Pots

Depending on which variety of petunia you choose, choose a companion plant with a different growth pattern. If you plant trailing petunias in an outdoor pot, pair them with upright growing plants like boxwood topiaries, small ornamental grasses, or hostas. If you choose a small and compact plant, plant it with trailing plants like English ivy and creeping Jenny. 


Popular Petunias

The choice of petunia varieties is overwhelming. We have gathered some classic examples of different types of petunias that will work in most garden spaces.

  1. ‘Crazytunia Red Blues’

crazytunia red bluesView in gallery

This is a classic style petunia with deep red blossoms that lighten in color at the outer edges. It is a hybrid variety, so it stands up better to the rain and the sun. It works well in containers and hanging baskets.

  1. ‘Daddy Peppermint’

Daddy Peppermint’View in gallery

The Daddy petunia series are grandifloras of the old style. These have lush and vibrant large flowers. The ‘Daddy Peppermint’ has a light pink petunia flower with darker pink veining. It is suitable for yard as well as container planting.

  1. ‘Wave Blue Petunia’

Wave Blue PetuniaView in gallery

This petunia has stunning deep purple/blue flowers and an easy care style that works for every home gardener. It will spread in record time and provide blooms all summer long.

  1. ‘Sophistica Lime Bicolor’

Sophistica Lime BicolorView in gallery

This gorgeous grandiflora petunia has bicolored leaves that are pale lime green and rose. They are suitable for the inexperienced gardener and work well in container gardens.

  1. ‘Easy Wave Burgundy Star’

Easy Wave Burgundy StarView in gallery

This trailing petunia has deep burgundy flowers with attractive white stripes originating from the center. It works well in containers and small garden spaces.

  1. ‘Prism Sunshine’

Prism SunshineView in gallery

Prism sunshine is a grandiflora with pale yellow flowers. These flowers are easy for home gardeners and hold their color all season long.

  1. ‘Supertunia Really Red’

Supertunia Really RedView in gallery

This is a deep red mounding petunia that is self- cleaning and easy to grow.

Frequently Asked Questions (FAQ)FAQ

How do I know when to plant petunias?

If you are planting petunias outdoors and you live in USDA Hardiness Zones 9 or lower, plant petunias after the last frost. If you are starting petunias from seed, you can start your seeds 8-10 before the last frost of early spring.

Where can I find petunias for sale near me?

Petunias are a popular plant and available at almost every home improvement store and plant nursery. If you do not live near a convenient location, you can order petunia seeds from almost every nursery online.

How long do petunias last in pots?

For outdoor pots in USDA Hardiness Zones below 10, petunias will last from early spring into the fall. You can also overwinter petunias inside. Petunias in indoor pots can last much longer, up to 2-3 years, if you water and fertilize them well.

Are petunias annual or perennial?

Petunias are considered a tender perennial. They will grow as annuals in USDA Zones 10-11. For those in the rest of the country, they should be considered annuals.

Conclusion

It is easy to understand why petunias are so popular. They are easy to grow and provide wonderful summer color. Also, there are so many varieties that you can try new ones each year.

Try a trailing ‘Easy Wave Burgundy Star’ to add exciting color to your front door or porch.

Or, use a more sophisticated variety like ‘Prism Sunshine’ to add depth and texture to garden borders.

Whatever variety you choose, your petunias will earn your confidence in them all season long.