The Complete Guide for Mexican Hardy Petunia (Ruellia X Brittoniana) Care

The Mexican Hardy Petunia, otherwise known as the Ruellia X Brittoniana or Mealy Cup Sage ‘Blue Bedder’, Mealycup Sage ‘Blue Bedder’, Farinaceous Sage ‘Blue Bedder’, is a rather well known perennial plant by gardening enthusiasts around the world.

Best known for its low maintenance and moderate growth, this perennial will likely liven up your house (or garden) with its dark green colored leaves. But, only if you learn how to take proper care of it for it to thrive.

This is why all the topics you need to know in order to achieve this will be covered in this Mexican Hardy Petunia Care Guide. Ready? Let’s go!

The basic care guidelines you need to remember for your Mexican Hardy Petunia are the following:

  • Water: The Mexican Hardy Petunia prefers constant watering each week and more during the hot season.
  • Light: Keep your Ruellia X Brittoniana in an environment where it can receive partial to full sun on a daily basis. 
  • Soil: Make sure to keep the Mexican Hardy Petunia in soil with moist but well-draining properties, so ideally, one that is made of sand and loam.

That’s it – sunlight, water and soil! The basic 3 fundamentals for all plant care, and with the Mexican Hardy Petunia this is no exception. With these three elements, your leafy friend will live healthy and happy.

Mexican Hardy Petunia care

Scientific / Botanical Aspects

In botanical terms, the Mexican Hardy Petunia belongs to the Lamiaceae family, the genus Salvia and the species Farinacea, hence its scientific (or botanical) name Ruellia X Brittoniana (roo-EL-ee-uh brit-tone-ee-AY-na).

As with other Salvia’s, the Mexican Hardy Petunia is a herbaceous plant, which means it will die back to the ground every year. 

Growing Region

The Mexican Hardy Petunia is a plant native to the S. Central U.S.A. to NE. Mexico.

Knowing your plant’s native region is very useful, as it can give you tips on which environment is best for your Mexican Hardy Petunia. If you keep it in mind, you can try to replicate these conditions at home, and you’ll likely end with a healthier plant.

With this in mind, the Ruellia X Brittoniana will be most used to the heat zones in the 1 – 12 region, as the plant hardiness level falls between 8b, 8a, 9b, 9a, 10b, 10a and the ideal climate zone is between 7, 8, 9, 10, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, H1, H2.

Growth and Size


In terms of size and growth, the Mexican Hardy Petunia is a relatively moderate grower, which makes things somewhat easy for any plant enthusiast.


But, how big does the Mexican Hardy Petunia actually get? What should you expect in terms of size? Let’s dive right in…

The Ruellia X Brittoniana can grow up to 2′ – 3′ (60cm – 90cm) in 2′ – 3′ (60cm – 90cm) and 1′ – 2′ (30cm – 60cm) in 1′ – 2′ (30cm – 60cm). 

These dimensions make the Mexican Hardy Petunia a relatively medium perennial compared to others, so it’s best to keep this fact in mind since it will affect where you want to keep yours at home.

Also, expect it to grow in a wonderful rounded, and spreading shape, which is something worthwhile to remember when making your garden landscape plans.

This is why experts recommend keeping an area of approximately 18″ (45cm) free so the Mexican Hardy Petunia can spread to its best extent.


In terms of watering, the Mexican Hardy Petunia is a fairly simple plant to take care of.

This is mostly because it has a straightforward watering schedule and somewhat regular watering needs.

Specifically, most experts agree that the Ruellia X Brittoniana prefers constant watering each week and more during the hot season.

Which is why it is considered a plant with relatively average needs in terms of water. 

Mexican Hardy Petunia plants


As a rule of thumb, you should remember to keep your Mexican Hardy Petunia in soil with moist but well-draining characteristics, as these will guarantee the right conditions for your plant to grow and thrive. 

When you consider this, this is why you should aim to choose soil that has good drainage, moist, and occasionally dry properties to keep the right moisture levels at all times. 

But, if you want a ‘one-size-fits-all’ solution to watering your Mexican Hardy Petunia then you should consider the famous ‘finger’ test. To perform this test, you just need to put your finger in your plant’s soil and determine if it’s moist or not. If it is, then don’t water; if it isn’t, then please do. In any case, this test will allow you to know if your Mexican Hardy Petunia needs or does not need water, every time.

Soil Mix

As mentioned earlier, the Mexican Hardy Petunia prefers to have soil with good drainage, moist, and occasionally dry properties at all times, reason why you need to make the soil mix out of sand and loam.

This is why most experts agree that the Mexican Hardy Petunia requires soil with clay, loam (silt), and sand, which will give you the right conditions it needs.

In addition to this, expert gardeners recommend having preferably alkaline, acid or neutral soil.

Light and Exposure

In terms of light & exposure, the Mexican Hardy Petunia requires partial to full sun in order for it to thrive under the right conditions. 

Most experts agree that this perennial will do well as long as you keep it in full sun, and it will be able to grow properly.

Specifically, we recommend that you place your Ruellia X Brittoniana in little to partial shade (only 2-6 hours of direct sunlight a day), to full and direct sun (more 6 hours of direct sunlight per day).


Being a herbaceous plant, the Mexican Hardy Petunia will die back to the ground every year. 

But, you can expect it to have its ‘prime-time’ during the spring (late), the summer (early, mid, late), and during the fall.


In particular, this perennial is well known for its long bloom season and showy flowers around the plant enthusiast community.

The Mexican Hardy Petunia produces some beautiful purple, or purple/lavender, blue and white flowers around this time of year.


The leaves from the Mexican Hardy Petunia have a beautiful dark green color during most of the year.

In particular, they have a opposite organization in its leaves.

Mexican Hardy Petunia up close

Attracts, Tolerance and Resistance

The Mexican Hardy Petunia is well known for being able to attract hummingbirds and butterflies, so keep that in mind when choosing your plant, as you’ll likely end up finding one or another in your garden.

Additionally, it has a special tolerance for dry soil, drought, clay soil and animals like rabbit and deer, so don’t worry if any of these come along, your Ruellia X Brittoniana will be fine.


How should you then organize your garden to include your new Mexican Hardy Petunia? Here are some recommendations by expert gardeners.

Most Ruellia X Brittoniana owners agree that this perennial will look great in most mediterranean and rustic gardens of all types. 

Other owners consider that they complement well most gardens of informal and cottage, city and courtyard, coastal garden, and in mediterranean garden styles. 

In particular, the Mexican Hardy Petunia’s best location within your garden is in patio and containers, banks and slopes, beds and borders, and in wall-side borders, others use it for landscaping in a urban garden, rock garden, poolside, mass planting, container, coastal exposure, border, or a very wet areas.

Companion Plants

Mexican Hardy Petunia’s do well with some other plants beside it. One good companion plant is the Coreopsis, which will pair up nicely with your leafy friend.

Others consider that a nice Chrysanthemum will work well too, so choose whichever you find works best for you!


Even though we covered a lot of care information for your Mexican Hardy Petunia, remember the basics: sunlight, soil and water, as these should be enough to grow a healthy plant at home.

Sebastian Moncada

I’m also a plant enthusiast and researcher. I’ve been privileged to have lived my whole life around the wilderness of Colombia and I’m happy to share everything I learn along the way. “Adopt the pace of nature. Her secret is patience” – Emerson.

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