Cypripedium Pot Culture

Pot Culture of Cypripediums

Wilford B. Neptune, M.D.

Cypripedium formosanum 'Trident's Twinkle Toes' CCM/AOS. This clone demonstrates unusual vigor. I started with two, mature growths in 1994; these flowered with one blossom in 1995; in 1996, there were four growths and two flowers; in 1997 there were seven growths and four flowers; in 1998 there were 15 growths, and seven of these had eight flowers (it received a CCM/AOS); and in 1999 there were 25 growths with 15 flowers.

I grow 10 different Cypripediums in pot culture. These are planted in a woodlands type compost, and started up in the spring. I usually start these in the cool house (min night temperature of 48F), in with the Paphiopedilums, and continue through flowering, and then they are put outside where they will obtain some sun, but being careful not to burn the foliage. They are kept moist, and fed with quarter strength fish meal and seaweed every week until the first of August. Only water with a low salt content should be used, and if there is any question, use rain, distilled or RO water. The fish meal fertilizer should be a preparation free of chlorine which is often added to cut down on the odor. After a hard frost the foliage is cut off, and the pot is placed in a double plastic bag and put into a refrigerator at 35-40F for a minimum of three months for cold dormancy. This is essential to produce leaves the following spring when the growth cycle is repeated. I have used a coldframe for the period of dormancy, but prefer the refrigerator as it offers better control of the temperature.

Cypripedium kentuckiense 'Trident's Old Ivory' CHM/AOS.
Cypripedium formosanum is probably the easiest of all the Cypripediums to grow in pots. Although hardy in New England, the plant may start growing with the Jan-Feb thaw, and subsequent cold weather may ruin the developing flower. This species can be reliably timed for blooming. For anyone wishing to grow Cypripediums in pot culture this is the one best suited for the beginner. This species has been managed in pot culture for the past 100 years in England, Germany, and China.

Note: I have not tried to grow Cypripedium acaule in pot culture as I have not found any reports of success beyond three years. Cypripedium reginae, Cypripedium kentuckiense, and the yellow lady's slippers, the small one, Cypripedium parviflorum, and the large one, Cypripedium pubescens, are easy and readily available.

Cypripedium pubescens (large, yellow lady's slipper).
I also am growing a few Asian Cypripediums: Cypripedium henryi 'Trident's Little Emerald' CBR/AOS; and seedlings of Cypripedium macranthum and a few hybrids. So far these seem to do about as well as North American Cypripediums, under the same conditions.

Woodland Type Mix

Start with three gallons of woods soil. This is from the top two inches of soil in a mixed forest, mostly white pine. This is hand rubbed through a 1/4 in wire screen. The result is a light, fluffy, fairly fine soil which does not compact, even when wet. To this is added 8 cups of fine peat moss, for water retention; 8 cups of fine and 4 cups of med Perlite, for aeration; and 1/2 cup of oyster shell and 1/4 cup of pelletized lime to buffer the mix to a pH of 7.2-7.4. The pot has one inch of drainage using marble chips.

Sources of USA Natives and Asian Cypripediums

Cypripedium parviflorum (small, yellow lady's slipper).
1. Carson Whitlow, Cyp Haven, 2291-280th St, Adel, IA 50003-8233
slipperguy@aol.com. Adult cyps, and Calopogons.

2. Owen Robinson, Raising Rarities, PO Box 405, Jacksonville, VT 05342,
802-368-7273. Adult Cyp parviflorum, pubescens, kentuckiense,and Pogonias.

3. Spangle Creek Lab, 2295 County Rd, Bovey, MN 55709. Only seedlings.

4. Roslyn Nursery, 211 Burrs Lane, Dix Hills, NY 11746. Adult Cyp calceolus,
and Spiranthes.

5. Barry Glick, Sunshine Farms, Renick, WV 24966, barryg@slip.net
Superb source of hardy perrenials. Has Spiranthes, Aplectrums, and
Tipularias.

6. Taida Orchids, No 100 Sec. 3. Chung Shan Rd, Da Tsun, 51506, Chang Hwa,
Taiwan, ROC. Asian cyps.

7. Scott Weber, Bluestone Farm Native Plants. S 5920 Lehman Rd, Baraboo, WI
53913. 608 356 0179

8. The Great Plant Company, POBox 1041, New Hartford, CT 06057
800 441 9788; Fax 860 379 8488 www.greatplants.com

Cypripedium reginae.
About Dr. Neptune

Dr. Wilford Neptune is a retired physician (Thoracic and Cardiovascular Surgery), and has a passion for orchids. He is not a judge, and has no commercial ties. Dr. Neptune originally grew under fluorescent lights, and acquired a greenhouse in 1972. He did not obtain an AOS award until 1982, an AD/AOS, but since then feels most fortunate, as an amateur, to have obtained 69 awards (if one counts the 8 AOS Show trophies) in 27 genera. In addition, there was one award for culture from the RHS-a Silver Gilt Medal (formerly the GM)- for Paph Neptune'Mars' AM/AOS.

Dr. Neptune's favorite orchid is Den. kingianum, and its primary hybrids; followed by nobile Dendrobiums, Lycastes, and his current challenge, pot culture of North American Native orchids, including all of the Cypripediums. In this latter group he has now received 11 AOS awards, including one flower award, an AM/AOS, on Calopogon tuberosus 'Jane'.

Dr. Neptune can be contacted at WNeptune@aol.com if you have any questions about his growing techniques.

Text and images copyright 1999 Wilford Neptune MD.
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