Mexican Petunia – How to Grow, Propogate and Protect (2022)

If you live in Mexico, the Caribbean, or the southwestern part of the US, you may have come across Mexican Petunias. This perennial shrub is one of those plants gardeners both love and hate for different reasons. For example, many gardeners love their tolerance for harsh weather conditions. Conversely, some others dislike their easy and often uncontrollable spread.

Mexican Petunias of the Ruella simplex species are also popular for their different names. Some call it the Mexican bluebell or Britton’s wild petunia. A typical Mexican Petunia grows to about three feet with lance-shaped leaves. Another critical feature of this ornamental is its petunia-like flowers.

Sadly, these flowers that can be blue or purple last for only a day. This isn’t a cause for worry though, as the plant produces fresh, beautiful flowers daily. Unfortunately, there’s some controversy surrounding the Mexican Petunia. Some will have nothing to do with the plant, while others want to continue its propagation.

If you’ve always admired Mexican Petunias then this article is for you. We’ll explain how to grow and care for Mexican Petunias, and you don’t even need any prior knowledge or skill with the plant. If you’re interested then continue reading to find out more.

How to Propagate Mexican Petunia

Growing the Mexican Petunia is a pretty straightforward process. In fact, this plant often self-multiplies. Therefore, many gardeners consider it invasive. Notably, you can propagate the Mexican Petunia through seeding, division, and cutting.

Below, we’ll explain all processes:

1. By Seeding

Propagating the Mexican Petunia by seed is the cheapest and least technical means. As we’ve already mentioned, Mexican Petunia seeds often grow by themselves. The steps below can help you establish Mexican Petunias in your garden through seeding.

  • Get a garden pot and fill it with moist, rich soil
  • Plant the seeds and cover with the soil
  • You can plant multiple seeds for each desired plant
  • Keep these pots in a warm area, away from direct sunlight
  • Ensure the soil is moist, and monitor its progress daily
  • After ten days your Mexican Petunia seeds should germinate

Then you can gradually acclimate them to the outdoors, before transferring them outside full time.

2. By Cutting

You can also propagate the Mexican Petunia by cutting from already grown plants. Here, you’ll need garden snips, a sizable pot, and good potting soil. Follow this process to ensure you get it right:

  • With your garden snips, cut a stem of about five to seven inches below a node
  • Shed the leaves from the bottom side of the stem
  • Now, dip this stem into powdered rooting hormone, and remember to shake off the excess powder
  • Put some rich potting soil into your pot and plant the petunia stem only a few inches deep
  • You can then place your potted Mexican Petunia stem into bright, indirect light
  • Once the stem develops roots, you can transplant it into your garden

3. By Division

Finally, you can propagate the Mexican Petunia by division. All you need to do is loosen the soil around the plant. With a shovel, slice the plant into different pieces. Now, transplant these divided plants into their new holes. These new planting locations must be of adequate size as well. After this, water your Mexican Petunia until it fully grows.

How to grow your Mexican Petunia 

After learning how to propagate the Mexican Petunia, the next step is to know how to grow it properly for the best returns. Below are the crucial points to note.

Site selection and preparation

As we’ve already stated, Mexican Petunia growing sites don’t require elaborate preparation. This site could be anywhere from pots to garden beds. In addition, you can plant the Mexican Petunia in loamy or sandy soil.

However, whichever one you choose must be rich and well-drained. Furthermore, the planting site should have neutral to acidic soil pH levels. Like many other plants, you should never transplant the Mexican Petunia in very hot weather.


Full sun exposure is good for Mexican Petunias. However, this doesn’t mean that they don’t do well in partially shaded areas. Notably, though, such shade can affect their beautiful flower production. Suppose you choose full sun exposure; your petunias will have purple stems. Conversely, they’ll have green stems in shades.


Mexican Petunias need just the right amount of water. They’re very adaptable to water conditions, surviving droughts and floods just fine. Watering is more crucial during the growing period. After that, you can reduce their water intake. Finally, it’ll be best to reduce watering during the winter until the soil dries.

Temperature and humidity

Mexican Petunias are hardy plants that are heat and drought-tolerant. So, they can survive in places with high humidity and heat. Conversely, they don’t handle cold climates well at all. They aren’t frost-hardy, so you must protect them in these conditions.


Mexican Petunias don’t need many nutrients to thrive. Therefore, they can do well even without fertilizers. So choosing naturally rich soil will be sufficient.

How to care for your Mexican Petunia 

Mexican Petunias are some of the easiest plants to care for. Once you plant them with the steps above, you don’t have much left to do. Now you just have to occasionally water the plant. The Mexican Petunia will survive well in most weather conditions.

Two important care activities for your Mexican Petunia include:

Pruning and deadheading

The Mexican Petunia’s flower dies daily. So, you have to pick off these dead flowers. It’s this process that’s called deadheading. You can also prune your plant if you don’t want it spreading indiscriminately. For example, you can cut off the seed pods to prevent spreading via seeds.

Potting and repotting Mexican Petunias

Mexican Petunias do well in pots. However, since they grow quickly, they can soon outgrow their pots. You have to re-pot your Mexican Petunia often. This means that you need a pot that’s 2 inches larger than your current pot. Then, remove the plant from its pot and transplant it into the newer garden pot. Finally, it would help if you exercised the same care you would during the initial planting.

How to protect your Mexican Petunia from pests 

Most plants are susceptible to pest attacks. However, not all pests are a threat to Mexican Petunias. Mexican Petunias aren’t notorious for pest attacks. There are just a few issues with this hardy plant.

Notable mentions include:

Spider Mites

Spider Mites are a large group of eight-legged arachnids that closely resemble spiders and ticks. But, they’re significantly smaller creatures. Like Mexican Petunias, Spider Mites also thrive in dry, hot weather.

They can suck plant juice out of the leaves of your Mexican Petunias. These activities can then leave your plant dry and covered with spots and blotches. Unfortunately, these pests are so tiny that noticing them can be challenging. It’ll thus be best to act proactively with Spider Mites by:

  • Spraying with water
  • Encouraging predators that are harmful to the insects but harmless to your plant
  • Using neem oil
  • Using organic pesticides such as Pyrethroid pesticides
  • Spraying with chemical pesticides
  • Hiring a tree disease specialist


The Mexican Petunias’ blooming period often attracts butterflies. While butterflies add color to your garden, their caterpillars can destroy your Mexican Petunia. They eat the foliage and buds, leading to significant damage. Fortunately, you can handpick the offending creatures off your plants. You can also use sprays to protect your Mexican Petunia weekly.


Thrips are pests that can infect your Petunias with viruses. These viruses can then make your plants develop white spots. In addition, they can adversely affect the plant’s leaves. They’re almost as tiny as Spider Mites, but you can still see them. You just need to apply neem oil or insecticidal soaps to keep your Petunia safe.

How to protect your Mexican Petunia from diseases 

The Mexican Petunia also isn’t plagued by many diseases. It has a strong resistance to diseases that generally affect other garden crops. However, some diseases are still strong enough to attack the Petunia. Find out how to protect your Mexican Petunia from these harmful diseases below.

1. Viruses 

Viruses get on your Mexican Petunia through small insects. They can cause yellow spots, mosaics, or halos when they do. Sadly, you cannot cure viruses. This means that you can only stem the disease’s spread in the plant. Therefore, you must routinely check your plants and start treating viral diseases. This way you can at least save the non-contaminated Petunias.

2. Root or Stem Rots

Root rot is also a threat to Mexican Petunias. It causes wilting and yellowing of leaves in the plant. Notably, rots are the result of poor drainage or overwatering. Therefore, it’s best to plant your Mexican Petunia in properly drained soil, and water your plants less frequently.

3. Powdery Mildew

The powdery mildew can occur in tightly-spaced gardens. This is because the absence of space obstructs airflow. Fortunately, you can notice this disease in your Mexican Petunia quickly. You just have to look out for white, powdery spots on the leaves and flowers. Treatment involves fixing your spacing problem, and applying neem oil.


  • You can choose the number of seeds in one purchase
  • Drought tolerant and adaptable to various soil conditions
  • Blooms best under full sun exposure
  • Grows to about 6 to 10 inches tall
  • No bloom or bud on arrival, so both can happen in your preferred location
  • Weight: 2.2lbs
  • Grows in wet and dry climates
  • Plants are freshly dug up on the day of shipping
  • Style: Mexican Petunia live plant

Choosing the Right Mexican Petunia Seeds

By now, you must already know how to plant a Mexican Petunia. The next step is thus to ensure you choose the best seeds. This is because the selection determines the growth and health of your plant. The Mexican Petunia seeds below are some of the best available, guaranteeing awesome results.

1. Emerald Goddess Gardens Mexican Bluebell Petunia Ruellia Simplex Live Plant – Top Pick

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Style: Mexican Petunia live plant

Weight: 2.2lbs

Number of planting pots: One 4-inch diameter pot

Once you purchase these Mexican Petunia plants, you can transplant them. The new spot could be bigger pots, baskets, or mixed perennial beds.


  • Grows to about 6 to 10 inches tall
  • No bloom or bud on arrival, so both can happen in your preferred location

2. Florida Foliage White Mexican – Drought-Tolerant Blooming Ornamental – Best Seeds for Colorful Garden

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Style: White Mexican Petunia

Weight: Weight depends on how many seeds you purchase

Number of seeds: Ranges from 3 – 60 plants

You must water these seeds regularly after the first growing season. However, you can reduce the watering schedule once they develop an extensive root system.


  • You can choose the number of seeds in one purchase
  • Drought tolerant and adaptable to various soil conditions
  • Blooms best under full sun exposure

3. Little Nest Live Plant – 5 Pink Mexican Petunia – Best Seeds for a Tropical Feel

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Style: Mexican Petunia live plant

Number of plants: One or two potted plants


  • Grows in wet and dry climates
  • Plants are freshly dug up on the day of shipping

4. Seed King Express Mexican Petunia Cuttings – Best Organic Seeds

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Style: Mexican Petunia cuttings

Length of cuttings: 6 inches

Number of cuttings: 3 cuttings

These cuttings do well in full sun exposure, and they fully bloom in the spring. In addition, spring is the preferred planting season.


  • Organic Non-GMO seeds
  • Requires little water
  • Can resist insects, although it’s still attractive to butterflies


If you want plants that can do well in tough, hot weather, you should choose Mexican Petunias. Their invasive nature is their only significant downside. So, if you can choose the right cultivar you can still enjoy this plant’s beauty for however long you want.

Follow the tips we have here to grow all the healthy Mexican Petunias you want.


Are Mexican Petunias illegal?

No, Mexican Petunias are currently legal in the US. However, some states such as Florida have classified them as highly invasive species. Invasive Mexican Petunias often have large, horizontal roots that are challenging to remove. Stumps can even regrow. No states have banned the plant though.

How long do Mexican Petunias last?

Mexican Petunias are perennial plants. So, they can last for three years or more in the right conditions.

How tall does Mexican Petunia grow?

Mexican Petunias can grow up to 3 feet within their lifespan. In addition, the plant’s width is often similar to its height. Notably, there’s a dwarf variety of Mexican Petunia. This variety grows to just about 1 foot.

Should you cut back Mexican Petunias?

If you love Mexican Petunias then their invasive nature is the only reason not to plant them. However, you can still grow this plant if you get a cultivar like “Purple Showers” that is non-invasive.

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