Growing Petunias

How to Plant, Grow, and Care for Petunias

Often grown as annuals, petunias are one of the most popular flowers because of their long flowering period. As with most annuals, they get leggy by midsummer, so you’ll want to prune the shoots back to about half their length. See how to plant and take care of your petunias to keep them blooming.

Pretty petunias are treated as annuals in most areas but also as tender perennials in Zones 9 to 11. The flowers come in many colors and patters, and bloom from spring until frost!

These colorful annuals can really add pop to a front lawn and often used as borders, containers, hanging baskets or even seasonal groundcover. Some even have a slight fragrance.

Height can vary from 6 inches to 18 inches. Spread can be from 18 inches to 4 feet.

Petunias are divided into different groups, mainly based on flower size:

Multiflora petunias are the most durable and prolific. They have smaller, but more abundant flowers and are ideal for summer bedding or in a mixed border (because they are more tolerant to wet weather).
Grandiflora petunias have very large flowers and are best grown in containers or hanging baskets (because they are more susceptible to rain damage). Theese large petunias often do not fare as well in the south because they’re prone to rot during humid, hot summers.
Floribundas: Floribundas are intermediate between the grandiflora and the multiflora groups. They are free-flowering like the multiflora varieties and produce medium-sized blooms.
Millifloras: Milliflora petunias are much smaller than any other petunias on the market. The flowers are only 1 to 1½ inches wide, but they are prolific and last all season!
Spreading or Trailing Petunias: These are low-growing but spread as much as 3 to 4 feet. They form a beautiful, colorful groundcover because the flowers form along the entire length of each stem. They can be used in window boxes or hanging baskets.

Planting

Petunias need full sun or they will become spindly. They don’t tend to flower in the shade.
They are quite versatile, growing in different types of soil, but it is important that the soil drains well and doesn’t stay wet.
You can grow petunias from seeds, but it is easier to grow them from transplants. If you are going to grow from seeds, start them indoors about 10 weeks before you want to set them outside. Petunia seeds are very small (dust-like!) and needs lots of light in order to germinate. Remember to water them. When the plants have three leaves, you can plant them outside.
It’s best to buy young plants from a nursery which often sells petunias in flats. Look for plants that are short and compact, not leggy and not yet blooming and they’ll settle in faster.
Plant after the last spring frost. (See your local frost dates) in a place that is sheltered from wind exposure. Keep well watered.
Space the plants about 1 foot apart.
If you’re planting petunias in containers, use a soil-less mix.

Care

Petunias are tolerant of heat so you don’t have to water them regularly. A thorough watering once a week should be sufficient (unless there are prolonged periods of drought in your area). Avoid watering shallowly as this encourages shallow roots.
Note: The spreading types of petunias and those in containers require more frequent watering.
Fertilize petunias monthly with a balanced fertilizer to support their rapid growth and heavy blooming. Double-flowered cultivars like a biweekly dose of fertilizer.

Getting Leggy in Midsummer

By midsummer, most petunias get leggy, producing blossoms at the tips of long, leafless stems. To keep petunias tidy and flowering, we prune the shoots back to about half their length. This will encourage more branching and flowers.
After pruning, fertilize and water the plants well to force out new growth and flowers. The plants may look raggedy at first but they’ll rebound with more color and blooms.
- Older garden petunia plants can be pruned prune hard (within a few inches of the base) to re-encourage vigor, especially in cooler climates, but keep the remaining leaves.
Also, remove faded, old, or dead blossoms to both improve blooms and attractiveness, especially for the larger-flowered petunias. Dead-heading prevents seed pods from competing for the plant’s food supplies. Clippings can be added to a compost pile to be recycled.

Pests/Diseases

Petunias have few serious insect or disease pests. Avoid wetting the foliage and flowers when watering to help prevent disease.

Aphids
Slugs

Recommended Varieties

Multifloras

‘Carpet Series’ is very popular. They are compact, early blooming with 1½-to 2-inch blooms that come in a wide variety of colors, and ideal for ground cover.
‘Primetime’ series stay compact and uniform, covered with 2¼-inch flowers.
‘Heavenly Lavender’ is an early, compact, double, deep lavender blue with 3-inch blooms on 12-to 14-inch plants

Grandifloras

‘Sugar Daddy’ (Petunia Daddy Series), which sports purple flowers with dark veins.
‘Rose Star’ (Petunia Ultra Series), whose flowers look striped because of its rose-pink flowers with a white center.

Floribundas

‘Celebrity’ series petunias are compact and rain-tolerant. The flowers reach 2½ to 3 inches across.
‘Madness’ series petunias have big, 3-inch flowers in many veined and solid colors. They are compact and bloom until frost. They bounce back well after rain.
‘Double Madness’ petunias are compact and floriferous with big, 3-inch flowers all through the summer. Like their single counterparts, ‘Double Madness’ petunias bounce back within hours of a rainstorm.

Millifloras

‘Fantasy’ forms neat, compact’Fantasy Pink Morn’, a milliflora type petunia.

Trailing Petunias

‘Purple Wave’ was the first cultivar in the class of spreading petunias. It produces large blooms of deep rose-purple. It is tolerant of summer heat, drought and rain damage. ‘Purple Wave’ remains under 4 inches tall.
‘Wave’ series petunias are available in a multitude of colors. Most are not quite as ground-hugging as the original. They are weather-tolerant, disease resistant and heavy-blooming.

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Reader Comments

Surfinias are the best for

Surfinias are the best for hanging baskets and for trailing .4plugs should be enough for a 12 inch basket.

Thank you so much Lesley, i

Thank you so much Lesley, i can't wait to see them blooming. It's officially spring but the temp here still under 30F at night.

I love growing petunias of

I love growing petunias of differen colors. they normally grow and bloom beautifully. I have bought new seedlings and planted them into the ground. prior to this i prepared the soil with a good classic fertiliser. however, much to my dismay i found that after planting there was bugs in the soil, so i treated this with a solution of rosecare3, and now i find that all the leaves have been eaten. I then mixed a mixture of classic plant food and sprayed them with it. Please help, what do i do.

Insecticidal soap, neem oil

Insecticidal soap, neem oil or horticultural oils will rid the petunias of many insect pests. You can make your own insecticidal soap or buy it at a garden center. Neem and other oils can be found at garden centers.

when is the best time for

when is the best time for plant outdoor flowers in dubai?

Petunias in dubai

Usually they bloom best mid November to Mid March - I am talking about petunias specifically - in fact they only appear in the shops once its season.
In summer , use vincas - though they flower much less than petunias...

I have an abundance of wave

I have an abundance of wave petunias in my garden. I plan on entering them in a fair. The judges have asked for 3 sprays. What is a spray? Is it 3 stems? A quick reply would be nice as I have to enter them in 2 days! Thanks in advance!

A spray can be a "decorative

A spray can be a "decorative flat arrangement of flowers and foliage." It can also be "flower arrangement consisting of a single branch or shoot bearing flowers and foliage." We'd recommend that you contact someone from the fair, to be sure that you are fulfilling their requirements for the show. Good luck!

I have beautiful yellow and

I have beautiful yellow and "black" petunias flourishing in my zone 3 garden, but even though it's still August here, it's starting to get colder, would Petunia's survive if I transplanted them from my garden, into a large pot and brought them inside or are they going to die anyways after their full season? Thanks!

Hi, Shanda: It's possible to

Hi, Shanda: It's possible to overwinter petunias, but not easy to get good results. The main things are to make sure they are pest- and disease-free after you (re)plant them in good soil, and that they get enough water and especially light. You can try planting cuttings from petunias, too. Give it a try, and good luck!

I have a large pink potted

I have a large pink potted petunia purchased from a nursery. It flowered well and now has buds but they just fall off. Can find no evidence of aphids or caterpillars. Weather in Brisbane, Australia is spring - currently around 70 degrees F., cooler in evenings. Some rain and plant is watered regularly. Any ideas? Thanks.

Hi, I moved into a new home

Hi, I moved into a new home in early spring and have been allowing the yard and garden to grow so i can see what surprises may pop up. So sometime in June I noticed a beautiful purple flowering plant next to the house on the edge of the grass. It looks like a petunia. It has grown and continues to bloom but the stems are now about 16 inches long. I propped them up on a stone. How do I know if they are trailing? They have stopped blooming at the moment. Any advice would be greatly appreciated. Thanks

When petunia branches start

When petunia branches start getting long and you can see where all the previous flowers were along the stem, it’s time to prune it back. This will refresh the plant at you will see new growth soon. You can spread any dried seed pods in the soil around the plant and you may get new plants popping up.

I have been trying to grow

I have been trying to grow petunias from stem cuttings but unable to do so . Have been following the procedure of cutting 3-5 inches of top stem , dipping in root hormone and then putting in the potting mixture in shade .

Hi. I found that stems work

Hi. I found that stems work best in water, but if you want to plant in soil then make sure it is very fine soil so the roots can grow (like seed growing soil). Put it in the sun, that may help too :)

I love my petunias. Bought 5

I love my petunias. Bought 5 hanging pots and they've thrived all summer with beautiful small deep purple flowers.
Had little spider mites but I use this recipe which not only helps control the mites but fertilizes as well.

In a quart spray bottle put one teaspoon
dishwashing liquid, 1 teaspoon ammonia and 1 teaspoon of rubbing alcohol. Then fill quart bottle with water.
Spray each plant about 20 times, then spray fresh water over them. That will help the mites to fall off.
Do this 2 times per week.

Enjoy your plants-They seem to attract hummingbirds(not moths) as well!!!!

Windex works as well. Then

Windex works as well. Then sprinkle with water to flush. Works aphid too.

The foliage of my petunias

The foliage of my petunias here in Myrtle Beach has been dying off the last few weeks. I still have a fair amount of flowers still but very little green leaves. Any solution or suggestion?

In Florida, petunias simply

In Florida, petunias simply grow best in early spring, winter, and fall seasons because they need cool night temperatures (45-65°F).

My new flowers wilt before it

My new flowers wilt before it blooms?

Wilting is due to uneven

Wilting is due to uneven watering. When you water the plant, do it thoroughly and then allow the soil to the dry out--close to the wilting stage but do not allow to wilt.
If you continue to have problems, it may be that the roots or crown beneath the soil is rotted. Make sure you provide good soil conditions and mix in lots of organic material and provide mulch. Water at the base of the plant, never on the plant itself.

Do I pinch off the ones that

Do I pinch off the ones that have little pod looking things inside the bloom ? Or are those the beginnings of a flower ?

Those pods will turn

Those pods will turn tannish-brown and will open and drop out little black seeds. These seeds can be used next spring to start your own plants. Start them 10-12 weeks prior to planting outside. If they have at least 3 leaves, then you are good to go!

My petunias got damaged by

My petunias got damaged by hail. A LOT of hail. There was a ton water in the pots so I poured off the excess standing water but the soil was still very wet. It has now been 4 days and my plants are starting to loom unhappy. The green stems and leaves are actually limp and not as bright green as what they have been the past month and a half. Any ideas? I am concerned that maybe there was too much water and it is drowning them?? Please help! Any ideas?

Petunias don't like to sit in

Petunias don't like to sit in wet soil. If the soil is still wet we suggest that you carefully remove the plants from the pot keeping some soil around the roots and spread them out on newspapers to dry. When soil and roots look dry plant them in fresh soil. Good luck!

Thank you. I took them out

Thank you. I took them out of their pots. Soil was still soaked with water. Thanks for your advice. They were Mother's Day gifts so I don't want them to die.

I planted petunias from the

I planted petunias from the nursery on May 29. Today is June 22 and the plants are getting taller but not bushing out. What should I do to make them look and grow better. We get very little rain and I water nearly every evening. If the soil feels dry at the end of my longest finger then I water heavier.

Hi, Louise: It sounds like

Hi, Louise: It sounds like you are on top of the watering situation. Hopefully, they are getting enough sun. Try cutting them back, which will encourage bushier growth. Also try giving them a shot of fertilizer once a week... just a little. Good luck!

Wanting to join this site

This is in memory of my sweet

This is in memory of my sweet neighbor, Alma. Alma had lovely lavender petunias all around in house in beds. There were also some plants that grew along the curbside. We are in central Alabama and each February, she would get out with her hoe and gently turn the soil over along the curb. In the spring the petunias would emerge and grow all summer. An interest note, we live in a small town and when the street sweepers came along, they would skip Alma's curb and leave the flower filled soil there. She explained to me the importance of turning the soil.