How Long Do Petunias Last? (The Flowers and the Plants Themselves)

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The stunning color of petunias can be the crowning glory of your flower garden, but it’s a shame they can’t be permanent.

There are two ways to answer the question “How long do petunias last?” The first is to look at the lifespan of the actual plant, while the second is to consider how long the flowers themselves will last.

As for the first question, the quick answer is that petunias can live between 2–3 years. During that time, they generally behave as annuals.

The second question is more challenging to answer because it’s difficult to put a timeline on each individual blossom. However, the general consensus is that they’re not particularly long-lived, but the plant puts out so many of them that you may not really notice.

How to Make Petunias Last Longer

There are two ways to help your petunias last longer than their intended 2–3-year lifespan. Take a look.

Move Them Indoors

When you want your outside petunias to live longer than a single season, your first instinct should be to protect them from the cold. The most effective way to do this is to bring them indoors.

You can plan ahead by planting them in portable containers to make the transition quick and easy.

On the other hand, if they’re already growing in the ground, you’ll need to carefully dig them up and repot them in early fall before the cold weather affects their health.

Once inside, you can treat them like typical houseplants until spring. This should extend the life of your petunias for an extra year or two.

Although, as I’ve previously pointed out, they do have a natural limit to their lives and will eventually wilt and die after an average of around three years, maybe more.

Save the Seeds

Saving the seed from your petunias isn’t quite the same as getting them to live longer. However, it’ll allow you to plant new petunias each spring without having to completely start from scratch with store-bought seed.

Not only do you save a little money by not buying new seeds, you can develop your own strain of petunias when you choose between the plants that thrive best in your garden.

Keep in mind that the next generation of petunia blooms may not look exactly like the originals because many of today’s petunias are hybrids, and not a ‘true breed.’

For best results, follow these steps:

1. Start by choosing a healthy, robust plant with lots of bright, colorful blooms.
2. When the blooms begin to wilt, avoid deadheading. Instead, give the dying flowers time to set their seed pods.
3. Then, once the blooms drop off, you’ll see a little bulb develop in its place. At this point, you need to keep a close eye on the plant or you might miss the seeds.
4. That little green bulb will turn brown and start to crack open. When it eventually opens up, that means it’s time to harvest the seeds.
5. Carefully snip off the pods and lay them out on a dry cloth or paper towel.
6. Then, place them in a cool, dry area away from direct sunlight for about a week.
7. Once they’ve fully dried, give the pods a light shake. If you can hear the seeds rattling inside, they’re ready to break open.
8. Next, gently crush the pods, and pick the seeds out of the debris.
9. Finally, store the seeds in a paper envelope to help keep them safe and dry until next spring when you can plant them and start growing a new batch of petunias.

How to Make Petunia Blooms Last Longer

Just as you can help your petunia plant last longer, you can do the same with their blossoms by providing them with proper care and maintenance.

Deadheading

The most obvious is to pluck off dead or dying flowers. Known as ‘deadheading,’ this technique is well-known among horticulturists and works to encourage flowering plants to produce more buds.

Light

The most important thing you can do for your annual flowering plants is to place them in an area that gets plenty of indirect sunlight. Remember, they’re not succulents, so they won’t be able to handle staying in the direct sun for too long.

Water

Petunias need to be watered whenever the soil starts to feel dry to the touch. Unless you live in a particularly dry climate or are just having a bit of a drought, you probably won’t have to concern yourself much with watering these low-maintenance plants.

The regular rainfall in your area should be enough to keep them happy.

Diet

All those luscious, vibrant flowers can come at a price. Petunias are quite the ‘heavy feeders.’ In other words, they require plenty of nutrients in the soil to keep them healthy and thriving.

When your petunias are outdoors, they need a dose of compost or aged manure once a month starting from late March until early July.

For those that have been moved indoors, the same rules pretty much apply. This means buying a standard houseplant fertilizer geared towards flowering plants and feeding it to your petunias once a week.

Types of Petunias

Petunias are among the most popular flowering plants. They’re a genus of nearly 35 species, all of which belong to the nightshade family of plants, Solanaceae, that are native to South America.

There are four different varieties of petunias to choose from. Longevity-wise, it won’t matter which one you grow as they all have a similar lifespan as well as similar flowering habits. The major differences between them are the range of colors within each series and the size of their blooms.

Grandiflora

The oldest and most common type of petunias are the grandifloras. They usually boast of large plants that grow up to 15 inches high and spread out between 10 and 12 inches wide.

Their blooms are bright and lively, but they tend to wear out by mid-summer, especially in areas that get excess heat and humidity.

Popular varieties in the grandiflora petunia series include:

• Daddy
• Dream
• Supercascade
• Supermagic
• Ultra

Milliflora

Milliflora petunias produce clusters of 1–1.5-inch blooms. The plants are smaller than their counterparts and can grow to a full adult size of about 8 inches tall.

Plants of this variety require minimal care, which makes it easy to grow them in hanging baskets or containers. Their blooms appear early and typically require no deadheading.

Two popular milliflora petunias include varieties in the Picobella and Fantasy Series.

Multiflora

The multiflora petunia plant is more compact in shape, but it’s still capable of producing quite a lot of small, delicate blooms. This particular type of petunia is known for its strong stem, making it suitable for windy climates.

Plus, the blooms are longer lasting compared to the Grandiflora petunias, particularly during the cold and rainy seasons.

As the name suggests, multiflora petunias are available in both double and single varieties, with the most popular being:

• Carpet
• Celebrity
• Horizon
• Mirage
• Primetime

Spreading (Wave)

If you want an area of your garden to pop with color, then planting some spreading petunias is the way to go. The blooms can grow to about 2 inches and generally don’t require any deadheading, while the plants themselves can spread up to 4 feet by the end of the growing season.

Wave petunias look great when planted in containers. Plus, because they’re better at tolerating heat and drought compared to other varieties, you can plant them outdoors underneath shrubs, flower beds, or vegetable patches.

The Avalanche, Easy Wave, and ShockWave are the three most popular varieties of Spreading petunias.

Final Thoughts

Now that you know how long petunias last, it’s time to pick out your favorite variety. No matter which one appeals to you, you can be sure that they’ll produce a range of rich, colorful blooms. 

Unfortunately, petunias are simply not going to last forever. Regardless, with a bit of extra work and attention, you can make them last longer and liven up your space, whether indoors or out.

You can also get spreading petunias for those spots where you want to really cover your space with color. Only 6 inches high, these ones can spread out several feet, still putting out flowers all the way.

No matter which variety appeals to you, there will be a whole rainbow of colors you can work with, in either solid hues or bi-color.

Unlike some plants that can easily outlive a person, petunias are simply not going to last forever. A little extra work and attention can make them last longer, and add a few more colorful years to your garden space.

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