Phragmipedium or South American Lady's Slipper Orchids

Pronounciation: frag-muh-PEE-dee-um
Common Name: Lady's Slipper Orchid
Distribution: South American tropics


Phragmipediums are the South American lady's slipper orchids which are found from Mexico through to central South America. Most of them are terrestrial or lithophytic, but some like the long-petaled caudatum types sometimes are epiphytic. Some species prefer to grow in the mist spray of waterfalls and on the banks of streams and rivers, which often get submerged during periods of heavy rain. These streams and waterfall dwellers include the species lindleyanum, longifolium, caricinum, kaieteurum, klotzschianum, pearcei, and sargentianum. I once read an article written by Glen Snyder in which he recounts a trip to a waterfall in Costa Rica, where Phrag longifolium quite happily grew in the constant mist spray from the waterfall.
Phrags flower mainly in late Winter or early Spring, but are known to bloom anytime as well. The sequential blooming species can be in bloom for six months or more on the same inflorescence, as the one flower drops the next bud is ready to open. Some of the easy-to-grow sequential blooming species are longifolium, pearcei, sargenteanum, and the miniature pink schlimii. Two of the slightly more difficult-to-grow sequential blooming species are the beautiful crimson-red besseae and the bright green boissierianum. All of the hybrids using these as parents also exhibit the same flowering behavior. A few sequential hybrids are Sedenii, Hanne Popow, Eric Young and Dick Clements.

Most Phrags prefer intermediate temperatures with nights around 10 C to 18 C. Phrags such as besseae and schlimii prefer slightly cooler temperatures. If kept much cooler in the winter, keep them somewhat drier as well, not soggy wet.

The long petaled caudatum types need bright cattleya-like light (3000 to 4000 footcandles), and ones like besseae and schlimii need a medium to low mottled leaf paph-like light (1,500 to 2,000 footcandles). Leaves should be a light green, not yellowish (too much light) or dark green (too little light). They should be firm, not long and floppy (more light needed). Higher light levels will result in more colourful flowers. You can avoid leaf burn by feeling the temperature of the leaves during the brightest part of the day, if they feel hot to the touch, they are in danger of burning and you should increase the air circulation or reduce light.

Watering and Humidity
Phrags prefer humidity in the range of 60-70% humidity When growing orchids in high humidity, you have to ensure constant air movement, so as to minimise any fungal problems. The caudatum types are most tolerant of a lower humidity, as long as the roots remain moist.
Good quality water is very important for growing Phrags. Tap water with low dissolved solids is fine, but distilled, rain or reverse osmosis (R.O.) water is usually even better. I use water from my fish ponds to water my Phrags, after every 4th pond watering I use clean freash water to leach out any salts which may have built up in the pots. Most Phrags should be kept moist at all times, except for the long pettaled types, these need to dry out a little between waterings ( at no time should they become bone dry, as this will damage the roots). I keep my "short pettaled" phrags sitting in a shallow dish of water for about 3 to 4 days, I then take them out of the dish and allow them to slightly dry out for 3 days and then return them to their dishes. To help prevent bacterial rot problems do not water over the tops of the plants on cool, cloudy days if the growths will not dry out by evening.

Repotting and Potting mixes
I prefer a medium grade pine bark mix specially made for orchids, it also contains nut shells and oasis flower sponge, to this I add some small stones and vermiculite. There are also various other potting midia such as osmunda, tree fern, bark, moss, CHCs (coconut husk chips), perlite, sponge rock and rockwool (extruded melted rock). Phrags should be repotted yearly, or as the medium decomposes, as they are kept wetter, the mix decomposes quicker. When it comes time to devide a large plant, I find it best to seperate the fans by gentley pulling or cutting it apart, leaving at least 3 to 5 fans (growths). These are the potted into a smallish pot as they do not like to be over potted.

A potting mix which I have found to work pretty well for me consists of the following:

10 parts small to medium sized bark chips
3 parts Sphrag moss
1 part silica sand, used for pool filters (can also use washed river sand)
2 part small stones
1 part Vermiculite

I find Phrags to be heavier feeders than paphs and as such they get a slightly higher fertiliser strength than paphs, but feeding too heavily can cause leaf tip burn. When using distilled, rain or R.O. water be sure to use a fertilizer with essential micro-nutrients. I use liquid fertilizers at half the recommended strength for three or four waterings then flushing thoroughly with clear water. During winter it is recommended to cut down the fertilizing.