Washingtonia Robusta vs Filifera – What Are the Differences?

One of the most recognizable palms on the planet would have to be Washingtonia palms.

The Washingtonia Robusta and Washingtonia Filifera are the two commonly cultivated varieties in the Washingtonia genus and can be found growing from the Gulf Coast to the desert southwest.

They offer great diversity due to their location tolerance, physical characteristics, and adaptability to different climates.

If you were ever wondering about the differences between the Washingtonia Robusta vs Filifera then keep reading!

TL;DR

In a hurry? Here’s a preview of what will be covered in this article:

Washingtonia Robusta (Mexican Fan Palm):

• Taller, slender trunk.
• Shiny, deep green fronds.
• Less cold-hardy but more moisture-tolerant.
• Reddish-brown petioles.

Washingtonia Filifera (California Fan Palm):

• Shorter, thicker trunk.
• Duller, deeply divided fronds.
• More cold-hardy, prefers drier climates.
• Lifespan of 80-250 years.

General Characteristics:

• Both adapt well to various soil and environmental conditions.
• Can become invasive in certain U.S. climates.
• Filifera tolerates lower temperatures than Robusta.
• Robusta thrives better in wetter areas.

Filibusta Hybrid:

• Combines features of both species creating a versatile cold hardy palm.
• Thicker trunk like Filifera, deeper green fronds like Robusta.
• Cold tolerance of Filifera, moisture tolerance of Robusta.

Maintenance:

• Requires regular seed clean-up to prevent a seedling infestation.
• Dead fronds on the palm can attract pests and be a fire hazard.
• Regular trimming of dead fronds is necessary for safety and a clean look.

What Are the Differences Between Washingtonia Robusta vs Filifera Palms?

The Washingtonia genus consists of two species; the W. Robusta (Mexican Fan Palm) and the W. Filifera (California Fan Palm).

While similar in many ways, there are some noticeable differences between these two palms.

Here are some key features and differences to consider if you want to grow one of these palms for your landscape.

Washingtonia Robusta (Mexican Fan Palm)

Washingtonia Filifera (California Fan Palm)

Where Will Washingtonia Palms Grow?

Washingtonia palms are quite adaptable to many soil and environmental conditions. 

These palms are so easy to grow that they’ve become an invasive species in certain areas of the U.S. given that they are in their ideal growing climate.

When it comes to cold tolerance, these two have moderate differences.

The Washingtonia Filifera is more of a dry climate lover than the Washingtonia Robusta and will take temperatures about 8 degrees F lower than the Robusta. 

They are hardy down to zone 8a in dry winter climates but can have trouble surviving wetter winter climates in these same temperatures and can get root rot.

The Robusta on the other hand does thrive better in areas with more moisture but isn’t as cold tolerant as the Filifera. 

Robustas tend to do best long-term in zone 8b and above in the more southern areas of the U.S., such as Texas, Arizona, and Nevada where the cold snaps are shorter and the summers are hotter.

Who Are Washingtonia Palms For?

Washingtonia palms are great if you are looking for something affordable, fast-growing, tropical-looking, and low-maintenance.

They are perfect for planting around swimming pools, decks, along driveways and entryways or to give your yard that classic “California” look, if that’s what you’re going for.

Don’t have a yard to plant them in?  No problem! 

These palms can be kept in pots for years, so if you live in an apartment, or condo or just aren’t ready to plant it in the ground just yet, they will do just fine in a pot with lots of light and occasional watering.

I have a 25-year-old Robusta that’s been growing since a seedling in a pot I’ve been hauling around for years. 

It’s never been fertilized, seen little to no direct sunlight (in some cases for several weeks at a time) and it’s still going strong! 

One day, hopefully soon, I’ll plant it in its permanent home.

Is There a Washingtonia Hybrid?

Since some of the differences in the two Washingtonia species can be minor, you will still find the Robusta and Filifera growing in many areas together. 

This has caused a common hybrid offspring of the two known as the “Filibusta”.

This Washingtonia hybrid appears to take on elements of both species, usually with a thicker trunk than the Robusta and deeper green fronds than the Filifera. 

The Filibusta palm can also have varying degrees of the hybrid appearance with some looking more like the Robusta or more like the Filifera.

The Washingtonia Filibusta also combines the cold tolerance of the Filifera with the moisture tolerance of the Robusta to create an even more versatile type of Washingtonia palm.

The Filibusta is a great species to experiment with in colder, wetter areas such as lower elevations and coastal regions of places like Oregon and Washington in the U.S. and colder, zone 8 areas of Europe where the Filifera and Robusta may not thrive as well on their own.

Any Drawbacks?

As mentioned before, these palms are very easy to grow and in their ideal climates, they can get quite “weedy”. 

They will drop thousands of seeds each year, so maintaining and cleaning up the seeds of these palms is very important so you don’t get an infestation of seedlings taking over in the spring.

A nice, but possibly negative feature of this palm (depending on your preference) is the petticoat of dead fronds that form under the crown. 

This is such a prominent feature of the Washingtonia that they are also referenced as the “petticoat palm”.

While this look is unique and can be visually appealing, the collection of dry, dead fronds can attract areas for pests such as rats, snakes, and other vermin to thrive.

In really dry areas, the petticoat shag of the Washingtonia can also be a fire hazard, since some of these fronds have been attached to the tree for years.

Needless to say, this can create a potentially dangerous situation around high heat or open flames.

Regular trimming of dead fronds over time will ensure these problems will be kept at bay, especially when these palms are planted near structures.

The Wrap Up

Both Mexican Fan palms and California Fan palms, along with the hybrid species are an excellent choice for your garden. 

They are also very affordable palms as well since they are so easy to maintain and start from seed.

While both species can withstand a variety of climate types, keep in mind that the Washingtonia Filifera will look its best in drier, desert climates while the Robusta will look and thrive best in mild coastal and Mediterranean climates.

For even more versatility, the “Filibusta” hybrid is a great choice as well since it combines the cold tolerance of the Filifera and the moisture tolerance of the Robusta making it a great option for many borderline growing zones.

As you can see, you don’t have to choose just one or the other in most cases, but knowing the minor differences between these species can give you an advantage of knowing what conditions your palm will need to look its best.