An Overview Of The Problem
Initially, Cypripediums.Com specialized in the asymbiotic propagation of four species of North American orchids: Cypripedium reginae, Cypripedium californicum, Cypripedium kentuckiense, and Cypripedium pubescens. However, in recent years I have expanded my interest to include temperate zone orchids from Asia and Europe. The range of habitats in which these species are found is huge and therefore one protocol/method for planting and maintaining orchids is unrealistic. In terms of successfully establishing a species it is helpful to understand its natural habitat. However, it is unrealistic to think that one can replicate these habitats exactly. The best one can do is to determine as best as one can the ranges of critical environmental variables and attempt to provide these. For a given species there are usually several ways that the levels of these critical environmental variables can be met. Also, environmental variables do interact with one another, ie air temperature and light intensity, adding to the complexity of the problem.
Here is a list of potentially important environmental variables:
1. winter air temperature (minimum temperature for aerial stems, minimum temperatures for corms and tubers)
2. summer air temperature (What is the maximum temperature for the species and what is the preferred temperature)
3. soil moisture levels, water retention, drainage ( summer versus winter)
4. soil chemistry- pH, mineral composition, organic content
5. necessity for a summer or winter dormancy period and its extent
6. light intensity- full sun or shade or some combination in between
7. soil temperature- summer
Cypripedium reginae, or the showy ladyslipper, is an orchid found associated with wet soils: bogs, fens, seeps, wet limestone cliffs, and springs. In the northern part of its range( ie Minnesota) the showy ladyslipper can be found over large expanses of habitat. However, in the southern part of its range (Missouri) its habitat is considerably more restricted. Here in Missouri we find the showy ladyslipper primarily in shaded calcareous fens and wet limestone cliffs, habitats that are shaded for much of the day. This is probably due to an interaction between high summer temperatures and sunlight in Missouri, an interaction which is probably not present in its northern habitat. See the photo below which shows the showy ladyslipper in a fen habitat. The soil is perennially wet often with calcareous groundwater (pH 8 or higher). Under adequate light conditions the showy ladyslipper flowers every year but the stature of the plant is only about 18-20 inches. One can also find showy ladyslippers in areas of considerable shade but here the plants don't flower and the plants are much taller with larger green leaves. In Missouri, the showy ladyslipper flowers the last week of May.
Cypripedium kentuckiense, or kentucky ladyslipper, is an exceptional North American Cypripedium in that it grows on alluvial floodplains. Often it is found growing very close to small streams and during heavy rains can be found submerged. The photo below shows the Kentucky ladyslipper growing within 6 inches of a small stream. I have measured soil moisture next to numerous Kentucky ladyslippers and have found completely saturated soils. This orchid is also found under a full forest canopy where it receives only dappled sunlight throughout the day. Apparently, it doesn't need full sunlight to flower. The Kentucky ladyslipper grows in sandy soils associated with alluvial floodplains. This orchid in Arkansas begins flowering the last week of April.
Cypripedium pubescens, the large yellow ladysliper, is a widely distributed orchid throughout North America. I have not seen this orchid in other regions of North America, so my comments on its habitat apply only to Missouri. Typically, the large yellow ladyslipper is found on north or northeast facing slopes under full forest canopy. See the photo below. Apparently, it receives only dappled sunlight throughout the day. In the Missouri ozarks the large yellow ladyslipper is found 10-20 feet above the valley floodplain. It grows in very shallow dry soils. The large yellow ladyslipper in Missouri begins to flower the first week of May.
Cypripedium californicum, the California ladyslipper, is restricted in its distribution to southwest Oregon and northwest California. It is common in the Siskiyou Mountains of coastal Oregon. This is another of the Cypripedium orchids that likes water. I have observed several populations in the Siskiyou Mountains.
This orchid typically grows along the edges of streams and in fens where water is very abundant.The photo above left shows the California ladyslipper growing in a seep alongside the road. This orchid is restricted in its distribution to serpentine soils. The photo above right shows the leaf of the rare California pitcher plant, Darlingtonia californicum, which often grows in association with the California ladlyslipper. In the above left photo, you can see flowers of the California pitcher plant on the right edge. The California ladyslipper begins to flower in mid-June. This is probably a zone 7 plant which may not survive the winter in the midwest or in other interior climates. One cannot say this for certain since the Kentucky ladyslipper found in Arkansas can survive winter in Minnesota. Heavy mulching with leaves is advisable with this species.
Planting Instructions For Cypripedium Vernalized Seedlings
The seedlings that you will receive have been vernalized a minimum of three months. The seedlings are ready to plant when you receive them. I do not know how much frost they can take so a wise man/woman uses the last frost date in your area as a guide. In St. Louis, I typically plant the seedlings sometime between March 15 and April 1. However, I have found that seedlings planted in June have enough time before frost to produce the dormant bud for next year's growth.
First of all, you need to realize that getting your seedlings to grow and survive the first year is the most critical period for your orchids. I have experimented for nearly a decade attempting to find the best medium to grow the vernalized Cypripedium seedlings. In the process I have killed at least 10,000 seedlings. In my opinion, the ideal medium must be free draining but yet hold adequate moisture and must be loose enough to allow oxygen down into the root zone. If the medium holds too much water and/or the medium has a high organic content the fungal pathogen known as"damping off" disease will take a heavy toll on your plants. If your medium is too compact or too wet, oxygen isn't able to penetrate to supply oxygen for the roots and the roots won't grow (= the plant dies or doesn't produce a dormant bud). I am now recommending a soilless mix, which I call the "Calanthe Mix" for all four of the Cypripedium speces discussed above. This mix was developed by my friend Carl Tilson from South Carolina.
Calanthe Growing Mix
1, 10" pot of western fir bark (fine sifted)
1, 10" pot of cypress mulch (fine sifted)
1, 10" pot of long-fibered sphagnum moss (fine sifted)--- (this is not peat moss!!!)
1, 4" pot of perlite
1, 4" pot of charcoal
1, 4" pot of crushed oyster shell
The western fir bark, cypress mulch, and long fibered sphagnum moss are sifted through a 1/2" mesh hardware cloth to obtain the correct size. The hardware cloth can be purchased at Home Depot. Mix all of the above ingredients well. As you are mixing it, add water so that all contents of the mix are moistened.
The only item that might be difficult to obtain is the long-fibered sphagnum moss. The best source of this is the Mosser Lee company in Wisconsin which sells 2 and 4 cubic foot bags. I have found this also at larger nursery stores. It can also be purchased from Hummert's International in St. Louis. One warning: When sifting the long-fibered sphagnum I recommend using a respirator for health reasons.
In planting your seedlings I recommend that you do not plant them initially in a bed, but in a container that can be moved. I recommend using a cement mixing tray (dimensions 20" X 27" X 6" deep) that can be purchased at the Home Depot. See photo below.
Fill the tray with 5-6 inches of the Calanthe Growing Mix. Wet the mix thoroughly before planting. Use your finger to make a 2-3" deep hole in the mix. Insert the seedling into the hole with the roots arranged vertically and the upper 1/4" of the shoot tip visible at the surface. Compact the mix around the seedlings. Place the mixing tray in an appropriate sunny location depending upon the species. Water carefully to avoid over-watering. You can insert your finger into the mix to check on soil moisture. The surface of the mix can appear dry while in fact the medium is moist just below the surface.
How much light should your seedlings have? I grow my seedings in a shade house which has a 70% shade cloth. The sun strikes the shade house for about 4 hours each day from 10AM to 2PM. After 2 PM, the shade house is in the shade. That should be shady enough? Depends upon the species. Cypripedium reginae and Cypripedium californicum grow in full sunlight in nature. Under the 70% shade cloth, they grow fine. However, Cypripedium kentuckiense and Cypripedium pubescens, normally shade loving species, suffer somewhat under a 70% shade cloth. Too intense sunlight causes a bleaching of the leaves. Bleached leaves have numerous white specks on them. See the photo to the right for this condition. Additional shading is warranted if you see this on your seedlings. In my experience, moderate bleaching is not lethal to the seedling.
Because the Calanthe growing mix is a soilless mix, it is advisable to fertilize the seedlings to get maximum growth. Orchids, in general, don't like strong fertilizers. I recommend fertilizing your seedlings every other watering. Use 1/4 teaspoon per gallon of Peters or Miracid 20-20-20 fertilizer. This will significantly improve growth.
After several months of growth your seedlings will show signs of dormancy-- the leaves will turn brown and shrivel up. This is partially a temperature dependent process- hotter weather promotes earlier dormancy. In St. Louis, Cypripedium reginae planted around the first of April starts to go dormant as early as August 1. To the inexperienced grower, this can cause a little panic-- "maybe I'm not watering enough". Don't panic and don't over-water. This is normal. Cypripedium kentuckiense enters dormancy later, usually mid-September or October. The photo to the left shows a dormant Cypripedium reginae seedling.
In order to gain confidence that your seedlings have not died you can carefully dig one up and check the status of the roots and the presence of next year's dormant bud. Notice in the photo to the right that this seedling has a dormant bud (whitish) at the junction between the stem and the root. Note also that the roots are whitish. These are viable roots. Dead roots are brown and mushy. Notice that this seedling is not dormant yet but it has already developed the dormant bud.
If growing conditions have been good, a dormant bud will be present and the roots will be 4-6 inches long and white. If you see just the ends of the roots as being white, this is also good because it indicates new root growth. If you see a dormant bud and long, white roots you have succeeded the first year.
Planting Instructions- 1-year- old, 2-year-old, and Older Plants
I have found that the Calanthe growing mix works well for 1-year-old and older Cypripediums. The only admonition here is that it is important to fertilize your plants because the Calanthe growing mix is a soilless mix without much mineral content. N-P-K must be supplied.
When you receive your 1- or older plants they should have been vernalized for several months at 4 degrees C. The planting and care of these plants is the same as for the vernalized seedlings with one exception. Since these plants already have a well developed dormant buds you should plant them so that the tip of the dormant bud is 1/2 to 3/4 inches below the surface of the soil. Planting them beneath the soil surface gives added protection against a late frost.
At some point you will probably want to plant your Cypripediums in a garden bed. A raised bed is best because it will likely have better drainage. I would recommend using the Calanthe growing mix supplemented with a small amount of organic material. I would place a layer of sand under the Calanthe growing mix to improve drainage. After planting your plant, I would add a layer of leaf mulch retard evaporation.
Considering that many Cypripediums don't flower until they are 5+ years old, there are many opportunities for disaster to befall them. One significant problem can be predation by animals. Each area of the U.S. has its own set of problems so it is difficult to generalize. However, plant predators can be categorized into below-ground and above- ground. In the midwest, below ground predators include moles, shrews, and chipmunks. Although not commonly known chipmunks, as cute as they are, are great tunnelers in your garden and cause damage to your plant's roots. To counteract below ground predators I recommend that all of your orchid beds be first lined with a geotextile underlayment-- the stuff that goes down when you are building a fish pond. This is followed by a layer of 1" chicken wire ( =poultry netting). When I first built my 30' x 35' shade house I did not use any of these protective measures. Subsequently, I was invaded by moles. Subsequently, I have removed the soil from all of my beds and have installed the underlayment and the chicken wire. Since then, no more rodent problems. The underlayment is also reasonably effective in reducing tree roots from invading your beds. Above-ground plant predators include the chipmunk again, gray and fox squirrels, rabbits, and insects. My shade house and other orchid containing beds are screened with the same 1" mesh chicken wire. With the exception of a few caterpillers my orchids are reasonably well protected. One additional comment is warranted. With heavy mulching with leaves, a healthy population of sowbugs (roly polies) has populated my orchid beds. Originally, I applied an insecticidal bait. However, I have found no evidence that the sowbugs are harmful to the orchids.
Other Orchid Species- Planting Instructions
Pogonia ophioglossoides, Pogonia japonicum, Eleorchis japonicum, Epipactis thunbergii, Platanthera clavellata, Platanthera ciliaris, Platanthera blephariglottis, Calopogon tuberosus, Calopogon pallidus--- I recommend planting these species in a bog that is filled with long-fibered sphagnum moss. The bog should be kept moist.
I am presently developing protocols for orchid species other than Cypripediums. These are mainly for the genera Dactylorhiza, Anacamptis, and Orchis. I will post these when I am satisfied that they are adequate. I am experimenting to see whether any of the genera/species can be planted in the Calanthe growing mix.