Planting, Growing, and Caring for Petunias
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Pretty petunias are popular because of their exceptionally long flowering period. As with most annuals, they get leggy by midsummer, so you’ll want to prune the shoots back by half. See more tips on planting and caring for petunias to keep them blooming.
About Petunias
Petunias are treated as annuals in most areas but can be grown as tender perennials in Zones 9 to 11. The flowers come in many colors and patterns and bloom from spring until frost!
These colorful annuals can really add pop to a front lawn and are often used in borders, containers, hanging baskets, or even as seasonal ground covers. Some even have a slight fragrance. Their height can vary from 6 inches to 18 inches, and they can spread along the ground anywhere from 18 inches to 4 feet.
Types of Petunias
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). These 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 multiflora groups. Like the multiflora varieties, they are free-flowering 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 and can spread as much as 3 to 4 feet. Because the flowers form along the entire length of each stem, they form a beautiful, colorful ground cover. 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 well in shade.
The soil should drain well and not stay overly wet, especially in containers. It should also be moderately fertile to promote the best growth. Amend poor soil with finished compost prior to planting.
When to Plant Petunias
- It’s easiest to buy young plants from a nursery that sells petunias in flats. Look for plants that are short and compact. Leggy petunias with tons of flowers already won’t settle in as fast.
- If you want to grow petunias from seed, start the seeds indoors 8 to 10 weeks before your last spring frost date. (See your local frost dates.)
- Plant young petunias outdoors after your last spring frost date, but keep a close eye on the weather forecast and protect young plants from late frosts.
How to Plant Petunias
- Petunia seeds are very small (dust-like!) and need lots of light in order to germinate.
- When the young plants have three leaves, plant them outside.
- Space the plants about 1 foot apart.
- If you’re planting petunias in containers, use a container potting mix that will drain well.
Types
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 are 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 mounds.
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.
Catherine Boeckmann
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Annuals life cycle is: from seed, grow, flower then produce seed pod and die.
To keep basket healthy remove pods and fertilize every week because the soil will Leech out fertilizer very fast as you water once a day. Basket will firm a round ball with blooms to brag about. Keep baskets moist all the time. When putting out new plants use a root stimulator water seedlings from the bottom, this encourages roots to form. When ready to plant roots maybe growing in a circle so gently spread bottom with your fingers in order for root to spread instead of continuing to grow in a ball. Roots will spread faster.
As the page above mentions (see right column), petunias prefer full Sun. However, they’ll grow in partial shade, too.
In purchased 2 hanging baskets from Lowes. They were beautiful and now as the flowers are blooming out..some of the vines/plantnt is dying..is there something i can do to prevent this#feeling concerned
What do the dead parts look like? If they're soft and squishy, then you could have rot due to overwatering and/or infection; if they're dry and hard, then it's more likely to be due to lack of water, or it could be due to an insect infestation - mine had an attack of whitefly (which is quite hard to spot on petunias because they're naturally sticky) and started to die off similarly, but they recovered after a spray.
I've been told to pinch off the dead blossoms to enhance more growth of blooms.
But should I only pull off the wilted blossom or should I pinch off the green cup and stem it is in?
Please help.
Thank you.
I just planted a variety of "Proven Winners" of Petunia's in containers that will hang from plant hangers or placed on a table.. and, the question above regarding pinching off the dead blooms... are they pulled off with the green cup or just the bloom....also I live in Florida and the sun gets
quite hot...can these small petunia blooms tolerate this sun for at least 5 hours? Thank you.
Susan, I am no expert but (well known fact) that just removing the dead flower head is pointless. You MUST also remove the green cup - this is where the plant will grow it's seeds! Failing to remove this cup the plant will think it is going to seed and will stop producing further flowers.
Pinch off the blossom only, and this should keep your petunia plant healthy for a longer period.
Everything else I have read states to pinch off plant about 1/4” beyond blossom. If blossom only is removed, the plant grows a seed which hinders regrow this. This sounds logical. Comments?
What is happening with the petunias when you see the leaves looking half dead and like it going to die. What can I do?
