Phragmipedium VS Paphiopedilum: What’s the difference?

Aren’t Paphiopedilums essentially the same as Phragmipediums? I used to think that all Lady Slippers were just another uncomplicated name for Paphiopedilums.

It was quite a surprise when I found out that Lady Slipper Orchids are actually three genera grouped together to form the Cypripedium Alliance:

Paphiopedilums,
Phragmipediums,
and Cypripediums.

Each group has quite different growing habits. In this article, you’ll learn to differentiate the two main genera, Paphiopedilums and Phragmipediums, but don’t forget that other tribes also make up the larger known Subfamily of the Lady Slippers. Some authors go on to place smaller tribes in with this larger group, such as the Mexipediums, and the Selenipedium.
What are the main differences between Paphiopedilums and Phragmipediums?

Phragmipediums will prefer higher light conditions, such as 2500 to 3000 foot-candles. Paphiopedilums, on the other hand, are more intermediate light growers, around 1000 to 1500 foot-candles.

Phragmipediums grow in or near water sources and can be submerged for long periods. Paphiopedilums require a drier potting medium and will not take to having their medium constantly wet.

Besides these two differences, there are other differences that the two distinct tribes of lady Slippers enjoy. Below is a quick chart but I’ll explain them one by one.

1) Tribe: Cyprepediinae
Subtribe: Cyprepedium
Genus: Cyprepedium
Subtribe: Paphiopedilinae
Genus:Paphiopedilum

2) Tribe: Mexipedieae
Subtribe:Mexipediinae
Genus: Mexipedium

3) Tribe: Phragmipedieae
Subtribe: Phragmipediinae
Genus: Phragmipedium

4) Tribe: Selenipedineae
Subtribe: Selenipediinae
Genus: Selenipedium

Phagmipediums	Paphiopedilums
Found in the Western Hemisphere	Found in Asia
2500-3000 foot-candles	1000-1500 fc
Requires tons of water	Prefer to dry out
Humidity 50 to 70%	Humidity 40-50%
Grow in streams Keep moist all the times More tolerant of decomposing media	Epythitic in leaf litter, rocks, and moss Need to be repotted yearly Sensitive to potting media
70°F (21 C) and 95°F (32 C) Warm Growers	Need cool nights 70-85°F (21-30 C)
Send out multiple flowers that bloom all at once or sequencially Seems like always in bloom	Needs to be older plant to flower May never flower if divided too early Unifloral or multifloral
More sensitive to the wrong Fertilizer Doesn’t need a lot	Terrestrial orchids in leaf litter, Need higher doses of fertilizer
Larger plants in general Faster growers	Slower to Develop

Location Differences:  Phragmipediums X Paphiopedilums

One easy way to distinguish Paphiopedilums and Phragmipediums are the physical location they grow in nature on the globe. Paphs are all from Asia, while Phrags are from the western world, starting in Mexico, crossing Central America and entering the northern and middle parts of South America. The Cypripediums, if you’re wondering, are all from the northern hemisphere and found in temperate climates.

QUICK NOTE: Paphiopedilums can be further divided into 6 types, and you can read about that in this article that describes the natural location and cultivation of each. For practical purposes, follow all the basic guidelines for Phrags when distinguishing between Phrags and Paphs, yet not all information from the section Phragmipedium section Phragmipedium apply. All the other 5 divisions will fit perfectly.

Phragmipedium section Phragmipediums
Phragmipedium section Himantopetalum
Phragmipedium section Lorifolia
Phragmipedium section Platypetalum
Phragmipedium section Micropetalum
Phragmipedium section Schluckebierium

Take into consideration the Himanopetalium, Platypelalym, Loriflolia, Mexipetolym and the Schluckebierium, since they are all river dwellers and prefer wet conditions. The Phrags section Phrags are epiphytic and grow in trees, which considerably changes their growing conditions. They are considered the “dry” Phrags.

Plant Growth: Phragmipediums X Paphiopedilums

Phragmipediums are extremely prolific growers. They are sometimes compared to weeds; they grow fast and spread like wildfire. I know those aren’t extremely technical terms, but that is what they are.

The leaves multiply so quick, that you have a huge plant on your hands in a short period of time. For this reason, they are considered to be good beginner orchids, since mistakes are easily handled by growing new roots and new leaves promptly. They also tend to be bigger plants, requiring more space to spread out.

Paphiopedilums, on the other hand, are slower to grow. They take their time, like most typical orchids, and enjoy the course of maturing with “sluggish peace”.

Light Differences: Phragmipediums Vs. Paphiopedilums

Phragmipediums are light-lovers. They need higher light conditions to grow. Compared to Cattleyas, they’ll need a little more and can be aligned with the Vandas. Phragmipediums will enjoy bright light and can handle direct sun for a couple of hours if it isn’t afternoon sun.

They do not get sunburned easily unless you sit them out in the hot, direct sun. They like the light, but not hot temperatures, which I’ll explain more later on. The only genus that doesn’t like the sun is the micropetalum, and you can grow them with your Phalaenopsis, around 1300-1500 foot-candles.

The Paphiopedilums can’t tolerate as much sun as their “cousins” can. They will most definitely develop sunburned leaves and purple spots quickly.

 There are a few tricks when these are grown when it comes to light preferences. If you keep the light on high and apply the high-light bright shade conditions to Paphiopedilums, they will develop waxier, leaves that lose their molting color.

The blossoms will be paler, not finding that beautiful, deep color the Lady Slippers are famous for.

Yet high lights will induce these orchids to proliferate vigorously, developing leaves and roots by the dozens. It’s a balancing act really.

Knowing how much light to give will be based on what you want from your orchid.

Watering Differences: Phragmipediums X Paphiopedilums

Watering is the main difference when it comes to growing these orchids in our homes. Phragmipediums are almost all (with exception of the first division, the Phragmipediums which include caudatum, warszevicizianum, wallisii, popveri, exstaminodium, and linderii) are grown near water sources. They sometimes grow in the river beds and can handle getting submerged for a few weeks at a time without being harmed.

They attach themselves to the leaf-litter and clay on the sides of the rocks near waterfalls and are constantly sprayed with water droplets from the river. Their roots are long and dangle down into the river bed, where they receive an abundance of water.

The only demand they have in terms of watering is that the water is clean, from a good source. Tap water won’t work in this case, since it has too many added elements (mainly chlorine) that react badly with the roots. Reverse osmosis water, rainwater, well water, or distilled water are all acceptable.

Paphiopedilums will not tolerate as much water. They prefer to dry out in between watering and like to “breathe” before they are wet again. They hate to have “wet feet”.

Another tip about watering: since the Phragmipediums will live in water, they don’t mind if the water is more acidic or more alkaline in terms of pH. If they had a choice, they’d drink a more acidic water, but they grow well in either. This applies to all the Phragmipediums except the kovachiii, which do not like the acidity. They relate more to the Paphiopedilums in this sense.

Paphiopedilums can’t stand acidic water. Since they are mostly terrestrial, they need high calcium carbonate concentrations and will enjoy a more alkaline pH of anywhere from 7.2 to 8.

Humidity Differences:  Phragmipediums X Paphiopedilums

In terms of humidity, both these orchids will like higher humidity. Phragmipediums will enjoy overly swamped humidity since they live next to rivers. This translates into a 50 to 70% relative humidity. Paphiopedilums inhabit the cooler climates, but still are quite humid from 40% to 50% rH.

In this sense, you will need to keep a fan running constantly to make sure you can provide the correct humidity but not a stagnant humidity. The non-moving, non-circulating water droplets will do more harm than any of the other topics. Root rot is a common concern since humidity is extremely high in both groups.

By the way, if you don’t have a humidifier, read this article where I explain the differences between the main types of humidifiers for orchids. If you want a suggestion, this is the one (Affiliate Link) I have in my home office. It’s small, but affordable and perfect for my small space.

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Flowering Differences: Phragmipediums X Paphiopedilums

Phragmipediums have overall bigger flowers. They are known for their huge blossoms, and the kovachii, a Peruvian Phragmipedium that was cataloged only in 2003, is the size of a 10-dollar bill. Absolutely gorgeous and huge.

Some Phragmipediums can have several blooms at the same time, blooming in sequence. Others only have one apical flower. If you have been cultivating Phalaenopsis orchids you might confuse this spike with a terminal spike, (which you can read about in this article) but this center growth is normal for this type of orchid. Your orchid is not dying.

Paphiopedilums are not as big, but just the same as heart-catching. They usually send out one apical meristem, which is a central flower spike and bloom one flower at a time. Further Reading Suggestions:

Don’t just take my word for what is written here. Continue researching other articles about the differences between Phragmipediums and Paphiopedilums because everyone has a different way of explaining orchids. Taxonomy is not always a clear-cut thing. Here are a few other articles from other websites if you’d like to continue your research on how the two orchids are different:

–Title: “Growing Paphiopedilums and Phragmipediums in Your Home”  written by Mrs. Kimberly A. Kehew,  published on American Orchid Society talks abouthow to care about these two orchids inside your home and the main differences between them in terms of culture and care.

–Title: “The Genus Phragmipedium“. Usually I don’t add a file like this one, but this time, I couldn’t resist. The information is just too good. For the life of me, I don’t know what this article originally is, but it looks like copied and pasted articles from different renown orchid magazines, all written by Karl Varian. The information is sound and all valid, and the pictures are fantastic. So, take a look to reference pictures to certain flowers and growth habitats.

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I hope this article cleared up a few things in terms of Paphiopedilums and Phragmipediums, and hope to see you in the comments.

Happy Cultivating!