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Do Petunias Spread? (All You Need to Know)

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Petunias are considered one of the prettiest flowers that have this exceptional bloom that lasts for a long period.

They are commonly considered as annuals in most regions of the world. Furthermore, they can also be grown as perennials in Zones 9 to 11.

As with most annual flowering plants, the petunias also can get leggy by the mid-time of summer. This is why we should take some extra steps to take care of them and prune the tips back to at least their half-length.

There are hundreds of different variants of the flowering plant and none of them will disappoint you with their colorful blooms.

They will always put a show for anyone passing by your garden or front lawn. Furthermore, some of the variants of petunia also have a slight fragrance as a bonus.

Keep reading below as we discuss how to take care of them and about some of their different varieties as well as if they will spread or not once planted.

Do petunias spread?

Petunias do spread. It only takes about five to fifteen days at room temperature for the petunias to spread. They spread at such a rate that they will cover a huge area in just one growing season. Although they need to be watered regularly and be well-fertilized too for the spread to happen.

There are about 35 species of Petunias in the wild. They can come in various colors and shapes that are both vibrant and awestriking.

People can be overwhelmed with which petunias to get if they are looking for something that will only stay in the backyard or something that will cover their yard.

We have taken a few of the petunias that are very frequent and common and briefly talked about their spreading behaviors below.

Mexican Petunias:

Mexican petunia also goes by the name desert petunia. They can easily spread from a nursery seedling or even from a young plant. Generally, they produce 3 feet tall stalks that are semi-woody within a month or two.

The Mexican petunia has shrubs that can carry purple or sometimes blue flowers on dark stems that stay for a long period of time.

This variant of petunia can self-seed easily and overwhelm the garden if not taken control of. Each flower of this species lasts a day.

Wave Petunias:

These petunias are a favorite ground cover among gardeners. They can bloom profusely and they spread in areas as wide as 3-4 feet.

Wave petunias also go by the name of trailing petunias, as they spread several feet even in large open areas such as outdoor floors. Normally petunias do not spread that aggressively from their plantation spot.

Regular Petunias:

These petunias can take from 6 to 8 weeks to flower after they are planted. It is recommended to start them in a moist environment with fertilized soil.

After that, we are able to move them outside, which can be around 10 to 12 weeks later. It is not advised to put the regular petunias outdoors before it at least has 3 leaves.

Do all petunias spread? What kind of petunias spread?

No, petunias might have a reputation for spreading. Not every petunia is like the trailing or more commonly known as the wave petunia. Petunia such as the Grandiflora petunia can have large blooms that can reach up to even five inches.

However, they do not do well in large spaces and do not spread like the wave petunia. They thrive well in enclosed spaces or flowering pots. There are other similar petunias out there that also do not spread that much.

On the other hand, the aforementioned wave petunia needs to be planted in the ground within a vast area for it to spread.

These types of petunias are commonly known as ground cover petunias. Petunias like wave petunia will spread easily outdoors too.

How fast do petunias spread? How long does it take for petunias to spread?

A regular petunia will germinate within the first two weeks at normal indoor temperatures. However, this process can be faster by using a heat mat for the plant.

If we want the best results, we would need to place the sprouts under fluorescent lights for at least 12 hours daily. Doing so will create a spring-light environment for the plants.

Furthermore, after receiving such growth catalysts the plant will flower 6 weeks to 8 weeks in. It will not take long after the flowers have started to bloom the petunia will start to spread. Once they start spreading, they can cover vast areas sometimes.

How far do petunias spread? How much will petunias spread?

When it comes to how much a petunia can cover, the wave petunia has all the other petunias beat. They are called the groundcover or spreading petunias. They spread as much as space they get.

They can only be six inches tall, but the amount of ground coverage they get in one growing season is astounding.

However, the wave petunias do need proper care for them to spread so much. The spread can be from 18 inches to 4 feet. This makes them perfect for planting atop a retaining wall or scrambling down a hillside.

There are other petunias whose height can vary between 6 inches to 18 inches. The petunias are usually divided mainly based on the flower size. Among them, the multiflora petunias are the most prolific and resilient as well as spread the most.

Why are my petunias not spreading?

Imagine us getting a bunch of different petunias for our backyard garden or indoor decorations. We expect the plant to spread as per their reputation.

However, if that is not the case with us and the petunias do not spread, then we can understand it could be one of the reasons we list below.

Overuse of Water:

We understand that plant life needs water to promote its growth. In the case of petunias, it’s also prevalent. However, the amount of water we give them matters a lot.

If we happen to overuse the water, we risk potentially drowning the plant itself. Therefore, the petunia will stop spreading.

Lack of Fertilizer:

Aforementioned overuse of water also is similar in the case of fertilizer too.

However, in this case, if there is a lack of fertilizer then the growth of the petunia is hampered significantly as they require a lot of nitrogen.

Lack of Space:

If we insist on keeping the petunia in an enclosed area with a deficit of space then that’ll in turn make the plants unable to spread. An adequate amount of open space is needed for the spreading of petunia.

Lack of Sunlight:

All plant life needs sunlight. The same goes for the petunia.

Regardless of them not needing the sunlight the first few weeks are not how we are supposed to keep them when they bloom. The lack of sunlight will not allow the plant to spread.

How do you get petunias to spread?

Even though petunias are resilient and some of them can profusely spread, there is the case of sometimes they will not spread as they are intended to.

This happens when they are neglected and not taken care of properly. Here is a list of things that we can do in order for them to spread.


Sometimes we have to use fertilizer on the plants multiple times because once is not enough for them to spread.

Few of the new hybrid species of petunias that spread profusely need a lot of nitrogen to meet the requirements for spreading.

Thus, having a water-soluble fertilizer with a formula of 20-20-20 nitrogen can extensively promote the growth of the plants.

Pick/Snip off old flowers:

To promote the growth of the petunias we need to trim or pick off the old flowers from the plant from time to time. This will result in more spreading.

Provide Space:

Space is very important for the plants to spread and have growth spurts. If adequate space is not available the petunias will not spread so providing them with the required space can help them spread easier.

Keep them watered:

The addition of water along with adequate fertilizer will enrich the plants to promote the growth of the spread. So, make sure to regularly water the petunias.

Final Thoughts

Petunias are one of the most popular perennials. There are hundreds of different petunias. Even though they can spread naturally, there are new hybrids of petunias that spread profusely. If they meet the requirements of water and fertilizer as well as adequate sunlight, they will spread all over.

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