Propagate Petunia Cuttings: How To Root Petunia Plants

by johnah on November 5, 2020

How to Root Petunia Plants?

Rooting plants is one of the most difficult tasks for gardeners. There are many varieties of plant which need rooting, but not all of them have the same requirements. For example, some plants like roses require a very high level of moisture in order to grow well, while other types such as lettuce do not require much moisture at all.

There are several methods for rooting plants, but they all involve using a special type of soil called ‘root zone’ or ‘soil’. The method used depends upon the species of plant being rooted. Some roots require a low level of moisture and others require a high level. Soaking the root with water will make it easier to root, but will not guarantee success.

If you don’t soak your root before planting, it may rot if left out too long without water.

The best way to root a plant is to place it into a container with moistened soil and then cover it with another layer of moistened soil. After the first week, the roots should start growing through the top layer of soil. Then you can remove the second layer of soil and continue until your desired size is reached. You can also use plastic wrap over your plant’s pot so that no air gets inside the container during watering time.

While rooting plants requires a great deal of patience and attention, the reward is more than worth it. A single rooted plant can become an entire garden full of beautiful flowers.

How to Root Petunia Cuttings?

Petunias are a type of flower that can be easily grown from cuttings. In fact, growing them from seed can sometimes be difficult. This is a guide about growing petunia cuttings.

You will need:

sharp knife or pair of scissors (depending on cutting method)

rooting hormone (depending on cutting method)

paper towel or SeedStartingMix (depending on cutting method)

cup or other small container (depending on cutting method)

Take a cutting from your petunia plant, making sure you have at least two nodes (the areas where the leaves are attached).

There are several ways to take a cutting:

With a sharp knife or pair of scissors, cut off the petunia plant. Be careful not to damage any of the nodes. (See pictures 1 and 2)

Use your finger or a pencil to pull up the top layer of soil, and then carefully cut through it. You can use the same method as above depending on which one you are more comfortable with. (See pictures 3 and 4).

Once you have your cutting, it is time to decide how you would like to root it. If using the paper towel method, wet it thoroughly and place the cutting about half an inch under the damp paper towel. Place this inside of a cup or other small container (such as a plastic Easter egg) that has holes in the bottom for drainage. This keeps the cutting from sitting in water and allows the soil to dry out quicker.

(See pictures 5, 6, and 7)

Fill your cup about 1/3 full with your soil of choice. (I use a mix of 50% regular potting soil and 50% perlite.) Make sure that you do not fill it too high or the water could run over the top when you water it!

Once your cup is filled, place your cutting into the soil. The top of the stem should be at or just below the soil. (See picture 8) Water it well so that the soil becomes evenly moist.

Place the cup in a warm, sunny location such as a windowsill. Check on it every day or two to make sure that the soil has not dried out. Add water as necessary. In a week or two, you should start to see new growth.

Once this happens, you can transplant your new petunia into a larger container and treat it as an established plant.

How to Root Petunia Cuttings in Water

In this method, a cup or small container is needed for each cutting you are rooting. A sharp knife, or pair of scissors can be used to cut the petunia cutting depending on what you feel comfortable with. The bigger the cutting, the better as long as you have at least 2 nodes with leaves (more nodes is even better).

Fill your containers 3/4 full with lukewarm water. Be careful not to get the water too hot!

Add a couple of drops of liquid plant food to each container.

Place your cutting into the water about 1/2 inch down. The leaves should be just above the water. (See picture 1)

Set the containers in a sunny window or some place where they can get lots of bright light. Check them daily and make sure that they stay watered and don’t dry out. Add more water as necessary. In 2 weeks your petunias should start to show new growth.

By the time the roots are 1 inch long, they can be transplanted into a soil mix. This is also when you can decide whether they are true petunias or some other kind of flower that has been seeded randomly in a pot of petunia that someone didn’t take the time to eliminate.

When they are ready, transplant them into pots using your potting soil mix. Place them in a sunny area and make sure to water them on a regular basis. They should be ready in a couple of weeks to a month.

The advantage to this method is that it allows you the freedom to start rooting several cuttings at one time since the containers can be assembled very quickly.

How to Root Petunia Cuttings in Soil

This method is less predictable than the above but can still produce good rooting results if you follow the directions.

You will need one or two pots (one for each cutting) and some potting soil mix.

Fill your pots 1/2 full with potting soil mix and water it well until it is evenly moist throughout.

Take your petunia cutting and prepare it as mentioned above. Make your cut one node down from a node that has a leaf on it. (See picture 2)

Sink the cutting into the soil about 1/2 way and firmly pack in around it so that there are no air pockets. Water it well.

Place the cutting in a sunny location and check it every day to see if it needs more water. In a week or two, you should start to see new growth and roots beginning. When this happens, transplant your new petunia into a larger container and treat it just like an established plant.

You can also do this with any other kind of flower that will root from cuttings. Just make sure to take a cutting from a node that has at least 2 leaves on it. (see picture 2)

How to Propagate Petunias from Seeds

Fill a container with potting soil mix and make shallow indentations (holes) in the soil. The number and size of holes will depend on the size of the petunia seeds you are planting. You should plant 2 to 3 seeds in each hole and cover them with soil.

You can also plant 4 or 5 seeds per hole if you want to get all of them. If more than one seedling comes up, then you can transplant the extras to other pots or plant them in the garden later.

The seeds should begin to sprout in a few days and will need to be watered when you water the rest of your plants.

They should be ready to transplant into individual pots or the garden in 4 to 6 weeks.

If you are growing them for cut flowers, they should be ready to bloom in about 3 months.

When planting your seeds, place them in a sunny location and keep the soil moist but not soggy wet.

Once they are large enough to handle, kids love to plant their own seeds and watch them grow.

By following these directions, you should have happy healthy petunias blooming all summer long.

These colorful flowers do best in full sun and in rich fertile soil that drains well.

When planting in the garden, you should space them about 12 to 18 inches apart. This will allow enough room for them to grow without becoming overcrowded, which can lead to diseases.

You can also grow them in pots or containers on your patio or deck. Just be sure to give them plenty of sunlight.

In addition to their beauty, petunias are a great source of nectar for hummingbirds and butterflies. Their sweet fragrance also attracts bees, which help with pollination.

So not only do they make a colorful and long-lasting addition to your landscape, but they are also good for the environment around them.

When it comes to deadheading or removing spent blossoms, this really is a matter of personal preference. Some people like to keep their petunias tidier and will remove the old flowers as they go.

Others will let them do their natural thing and only remove the finished blossoms before they ADD new ones.

Either way, your petunias will continue to bloom all season long if you keep deadheading them regularly.

Leave the spent flowers on until they turn completely brown or dry up before removing them to keep the bees and other pollinators coming.

If you aren’t sure what to do in your situation, try doing a little of both.

Deadhead some of them and let the rest go until they are finished. You can then collect all the seed pods that form afterwards and scatter them around next year.

Starting petunia seeds isn’t really that difficult, but they do have a bit of a long germination period.

It takes anywhere from 2 to 8 weeks before you should even see the first signs of sprouting.

Once they do start growing quickly, so be sure to keep them watered because they don’t like to get dry. (But don’t keep them soggy either or they may become diseased.

Also, don’t overwater them or they may get root rot. It is better to err on the side of less watering than more.

When growing petunias from seed, you can start them in peat pots, Jiffy Pots, or even newspaper pots. Whatever you use, just be sure to transplant them into larger containers once their roots begin growing through the bottoms of the starter containers.

As I mentioned earlier, petunias are fairly heavy feeders. You can give them a decent amount of plant food every couple of weeks during the growing season. Just follow the instructions on the fertilizer and water them in well after applying.

You can also top dress your petunias with some compost or potting soil when you transplant them into their final containers. A little now will save you from having to fertilize them as much later.

You should stake or cage large growing varieties to keep them from bending or breaking in the wind. They can also benefit from some shade when it’s extremely hot.

Other than that, there isn’t much else to growing petunias. They are a hardy flower and will thrive just about anywhere you planted them as long as they get what they need.

So give them a try this year and see for yourself why we have loved them for so long.

Happy Flowering!

Sources & references used in this article:

Dark exposure of petunia cuttings strongly improves adventitious root formation and enhances carbohydrate availability during rooting in the light by Y Klopotek, KT Haensch, B Hause… – Journal of plant …, 2010 – Elsevier

… daily light integral during propagation influences rooting and growth of cuttings and subsequent development of New Guinea impatiens and petunia by RG Lopez, ES Runkle – HortScience, 2008 – journals.ashs.org

Root formation in ethylene-insensitive plants by DG Clark, EK Gubrium, JE Barrett, TA Nell… – Plant …, 1999 – Am Soc Plant Biol

Piriformospora indica promotes adventitious root formation in cuttings by U Druege, H Baltruschat, P Franken – Scientia Horticulturae, 2007 – Elsevier

Carbon assimilation of petunia cuttings in a non-disturbed rooting environment: response to environmental key factors and adventitious root formation by Y Klopotek, E George, U Druege, HP Klaering – Scientia horticulturae, 2012 – Elsevier

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