Mexipedium xerophyticum Care & Culture

Orchid Species Name: Mexipedium xerophyticum

Care Group: Slipper Orchids

Overview: I split a flask of seedlings, purchased from Paph Paradise back in 2019, and have grown out 10 plants in a community pot since that time. For general context, care for Mexipedium is similar to Phragmipediums and Paphiopedilums. However, this species is called “xerophyticum”—a xerophyte is a plant adapted to life in a dry habitat and has mechanisms to prevent water loss or store available water. You’ll notice their leaves are quite fleshy like a succulent, it’s an adaptation to store water. Avoid harshly dry roots (though they are much more tolerant of this than both phrags and paphs) and avoid extended dryness or prolonged wetness. Regular waterings are important. So is a sharp period of dryness. I soak my plants weekly, with water up to the base of the plants, in a big bowl of water for 10 mins up to 2 or 3 hours. Then, I’ll drain them and put back under the lights. Light is moderately intense (compared to most other orchids). 12h/day under 4x18w (48”) strips from The Orchid Hobbyist (which works out to about 18w/ square foot of coverage). This species comes from limestone habitats, so they seem to need a bit of calcium (and you should avoid acidic root conditions). My tap water is alkaline, which works well, but if you have pure water (RO or rain), I would suggest adding oyster shells to the potting mix. Humidity is recommended to be high, but mine is terribly low—only 18-40%. Clearly, if you keep them hydrated, then they can tolerate low humidity. Other than that, slow and consistent wins the race…they aren’t fast growers, but they’re steady if happy.

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Mexipedium xerophyticum Care

This species comes from a uniquely extreme environment—growing on exposed limestone rock cliffs. Given seasonal changes (the dry season), it seems they are well adapted to periods of drought. The leaves are hard, thick and are structurally adapted to hold water, much like a succulent cactus. Overall, I feel they are easy to grow, but they seem to require more light than most other paphs and/or phrags. If the leaves are are a bright chartreuse to yellow you may be giving them too much light or not enough fertilizer. Dark green leaves that are long may indicate insufficient light. Plants adapted to limestone areas may not have the same resilience to conditions that are acidic so if your growing this plant in sphagnum or pure bark, you may find it’s not as robust, or that it gets root rot easily.

Photo of Mexipedium in situ on limestone rock cliff – notice how they cluster in the dark damp area

Photo by Eduardo A. Pérez García. From, The Rediscovery of Mexipedium xerophyticum

Mexipedium Orchid Care Tips – Caring for this species

Humidity: most claim the humidity should be over 75%rH. Mine is rarely over 40% and often averages under 35%. My opinion is that plant hydration (achieved with a regular watering cadence) is key to successfully growing this plant, not high humidity.

Hydration & watering: follow sharp but consistent wet/dry cycles, watering at regular intervals while avoiding prolonged wetness or dryness. I would say your goal should be to water, have the pot and roots dry within 3-5 days, and then water again; repeating this wet/dry ebb and flow indefinitely. Like I mentioned above, I soak my plant weekly, sometimes for many hours, but my potting media is mostly inert meaning it doesn’t get soggy.

I also believe that alkaline water is helpful. My plant gets Calgary tap water (shocking, I know) which has a pH of 7.9 and 250ppms calcium carbonate. When I was experimenting with pH down, this plant stalled growth, which to me is an indication that it may dislike acidity below 6.0pH.

Photo of Mexipedium being watered
Soaking in a bowl of water for ~1h)

Potting media: a chunky well-draining and airy potting mix is essential. The mix I use is mostly rock; about 50% pumice, 20% LECA, 25% bark (ideally Orchiata brand which is treated with lime), and a very sparse top-layer of sphagnum moss to hold moisture near the base of the plants a bit longer after watering. See photo below. I don’t think you need to follow this mix exactly; you could likely go as much as 60% bark to 40% pumice and still get the desired results. But whatever mix you use, it is important that it doesn’t compact (which would restrict airflow to the roots) and holds some moisture for a localized micro environment around the roots—in more direct words: I wouldn’t use pure sphagnum or peat-heavy potting mixes.

Image of potting media for Mexipedium

Fertilizer/nutrients: same as for paphs and phrags – organic fertilizer is good at quarterly applications, along with biweekly (every 2 weeks) applications of soluble orchid fertilizer at 1/4 strength.

Light: Moderately bright; target 5-25% filtered sun equivalent.

Photo of my lights & setup; the mexipedium have been grown on either of the bottom two shelves

Growth Patterns & cycles: Mexipediums are highly seasonal with flowers coming through around the peak of summer (June/July). Growth is very similar to other slipper orchids and starts with vegetative growth followed by flowering after the previous season’s growths have matured.