Mexican Petunias: How To Grow & Care [Guide]

Mexican petunias are evergreen flowering plants. They are referred to as flower factories because they produce lots of flowers. Flowers are mainly available in three colors white, pink, and purple.

Growing these plants is extremely easy. If you plant them somewhere and forget then also they will manage to grow. In this article, you will learn about how to grow and care for Mexican petunias.

So, let’s start:

Quick Guide

Common NameMexican petunia
Scientific NamePetunia spp.
Plant typeAnnual flower
Mature Size6 to 24 inches taller and 36’’ wider
Sun ExposureFull sun 
Soil Typefertile, well-drained soil
Soil pHSlightly acidic 
Bloom TimeSpring, Summer, and Fall
Flower ColorPurple, pink, yellow, white, red, orange, green
Hardiness Zones10 to 11 USDA (can be grown annual anywhere)
Native AreaSouth America

How do Mexican petunia look like 

They have long, strip-like leaves that are green in color. Flowers are trumpet-shaped with five petals. Just like daylilies, the life of their flowers is only for one day.

You will be able to see a clump of blooms in the early morning which will fade till afternoon.

However, this cycle repeats every day, meaning they bloom and fade regularly. Flowers start coming from early spring and keep coming till winter. 

Mexican Petunia

They are very hardy perennials, once planted they keep growing for years. Makes them one of the easy-growing flowering plants.

When to plant

Plant them after the frost or in the fall (a few weeks before frost). In frost, they go dormant. 

Do they grow in water?

Mexican petunias can grow easily in any kind of soil but they do not grow in water.

Where to plant

You can plant pots, containers, or directly in the garden. they are hardy plants that can survive in any condition. If you are growing in the pot, place it in the spot where they get direct sunlight. 
Do not relocate the pot frequently, they bloom in the direction of sunlight by replacing you may disturb their blooming process.

How to grow Mexican petunia in pots

They can be grown by division or seeds. You can choose any method, they grow very rapidly if you plant them at the right time. Plus they do not need extra caring.

Mexican Petunia

In fact, Mexican petunias are invasive, if not monitored they can spread all around the garden.

To grow in the pot:

  • Take a medium-sized pot around 11 inches wide. The roots like to spread deep so it is always better to have a wide and deep pot.
  • Make sure that the pot has adequate drainage holes, good drainage is a must for healthy growth.
  • Sow 2-3 seeds in the center of the pot. Do not need to sow seeds too deep, just press seeds against the soil.
  • Spray water to keep the soil moist, this plant requires more water as they bloom regularly.
  • Seeds take nearly 14 days to germinate, keep patience and let them get established.
  • Do not change the place of the pots frequently, it might disturb their growth cycle.

Related post: How to grow and care for wax begonias indoors

How to Propagate Mexican Petunia from cuttings

The division is an easy and fast method to grow multiple child plants. For division take stem cutting. You can cut any node branch, do not tear or crush the stem. It might leave permanent damage.

Clear all the buds and flowers from the stem cutting. Also, pluck all leaves from the bottom half of the plant. 

Mexican Petunia

Dip the bottom end of stem cutting in the soil and make it stand in the soil. You may dip in root hormones however this is totally optional, plants also thrive without any supplement.

Spray water to make the soil moist and leave it alone. After a couple of weeks, the stem cutting will get established. They generally self-grow and do not need to care much.

Mexican petunias

How to care for Mexican petunia

This flowering plant does not need special care. However, some conditions are beneficial for their growth.

Let’s see:


Mexican petunias are sun-loving plants, the more they receive sunlight the more they produce blooms. 

mexican petunia

Their petals open in the direction from where sunlight is coming so do not change their spot. They can withstand in the shade spot but will produce fewer flowers and might get wilt.

The color of flowers and stem will vary depending upon light condition- if planted in a more lighted area, more bright and shiny flowers will produce. 

Stems are more purple in light condition and solid green in shadier areas.


They are drought tolerant and survive if watered occasionally in a dry climate. However, for regular bloom, you have to keep the soil moist.

Their roots are tender so do not add much water, adding excess water might melt their roots.

When watering, always pour or spray water directly in the base, avoid wetting their flowers and stems. Its wet parts attract fungal diseases.

Related post: How to grow and care for marigold flowers from seeds


Mexican petunia can grow in different types of soil, but they preferred to be planted in well-drained, fertile soil. They grow and spread quickly in marshy soil, the soil which is found near lakes and rivers.

Then it comes about pH level, they can grow in alkaline soil type but most preferably in neutral or slightly acidic soil.

Temperature and humidity

If you live in a cold region then you may not be able to enjoy their beauty. 

These flowers do not thrive in cold or low-temperature climates but can grow in summer and behave like annual plants. 

Grow best in dry or desert conditions but may also grow in humid climates.


Pruning encourages more bloom since new flowers grow every day. You can pluck flowers that get wilt.

Mexican petunias produce flowers in the morning which get dry till evening, this is a continuous cycle. Pluck wilted flowers, so that new buds can grow.

Ruellia simplex

They do not grow much taller, just 3-4 feet high. So you do not need any ladder to prune them.

Mexican petunias are very invasive, if you have planted them in the garden you have to monitor them occasionally, else they can cover the whole garden.

You can control their growth by pruning, if you want to get rid of or remove small unwanted successors then just pull them out from the soil.


It is not mandatory to add fertilizer in Mexican petunia plants, generally, they are self-grown and do not need any supplement. However, you may feed them with fertilizer in growing months. 

purple flower

You can use a garden rake to mix in fertilizer of choice into the top two inches of the soil of surrounding plants.

If you are planting Mexican petunia for the first time, you can add organic compost or manure to the soil. This will help to boost the plant’s growth and produce a lot of flowers.

When to transplant

If you have planted in pots they may need to be repotted more frequently than other plants. As they are fast-growing shrubs. They grow well as long as planted in sunnier spots.

How to Winterize Mexican Petunia

Overwintering Mexican petunia is very easy, though they are perennial plants they do not produce flowers in the winter and like to go dormant.

If you have planted it in the pot, you can simply winterize them by Snipping off its leaves and cutting branches.

After Pruning, Placing the pot in a dark room or where light is less. On some days they will go dormant, do not water in this dormant period. It might feel like they die, but it will come back in the next growing season.

Bring pot out in the early spring, when there is no threat of frost. Mexican petunia will start growing normally with regular care in a few weeks.

Did I Miss Anything?

Now I’d like to hear from you: which tip from today’s post are you going to try first?

Or maybe, I didn’t mention your favorite plant growing tip. Either way, let me know by leaving a comment below right now.

P.S. I myself reply to every comment.

Before going if you want to grow beautiful flowers in your garden? Then click on these articles also.

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2 thoughts on “Mexican Petunias: How To Grow & Care [Guide]”

  1. Should I leave my potted Mexican petunia in the pot and transplant it in spring? Thanks for all the information in the article.

    • Hey Candy, Glad you found this article helpful.
      Yes, you can transplant it in spring. To protect from winter bring the pot inside, place it in decent light, and do not water. In early spring transplant it, with 1-2 weeks of regular watering and sunlight. It will return to normal.


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