Kingdom : Plantae
Order : Asparagales
Family : Orchidaceae
Subfamily : Cypripedioideae
Tribe : Cypripedieae
Subtribe : Cypripediina
Genus : Cypripedium
Growing specie cypripediums in the garden is relatively easy providing the right species are selected and the right conditions provided. There are some 65 species of cypripediums, all found within the northern hemisphere, ranging from Mexico to Siberia. There are, however, only a limited number which are seed grown or divisions of legally held plants. In particular there are only a few Chinese species which are bred. Any of the rarer species offered for sale are undoubtedly from illegally obtained stock.
It must be realised that any species obtained from outside Europe must have both CITES and phyto-sanitary certificates. Before looking at the individual species and their requirements it is important to be aware of the general cultural needs of cypripediums.
Hybrid cypripediums are the best way for new enthusiasts to learn to grow cypripediums in the garden or cold greenhouse. They, of course, exhibit hybrid vigour and are far less demanding than some of the species. Equally important is the fact that they have to be artificially raised so their production can have no impact on wild populations and it is obvious they are from bred stock.
Cypripedium hybrids are fully hardy and capable of taking temperatures below freezing but do not like hot summer temperatures. (they will take higher temperatures than many of the species). They should be grown in semi-shade with limited midday sun. They must never be water logged nor conversely allowed to dry out in the summer.
They should be grown in semi-shade with limited midday sun. They must never be water logged nor conversely allowed to dry out in the summer. This makes them ideal for cool slightly damp north facing aspects. Whilst they will grow in shrubberies or woodland they should not be too close to trees or large shrubs as they are unable to compete for moisture and nutrients. Suitable associate species include ferns, epimedium and smaller hostas. They also thrive when planted under a ground cover of Leptinella.
They need to grow in a deep well aerated crumbly soil which does not dry out in order to enable the root and rhizome system to develop over a wide area and also to avoid the dormant buds from rotting.If the soil is heavy the addition of grit or sharp sand will open it up. This will make it lighter and more free draining. Where the soil is sandy and therefore likely to dry out perlite, pumice or Seramis can be added in order to hold moisture; particularly in the summer. In addition leafmould or pine duff can be dug in and also used as a top dressing. It must be remembered that both materials will change the pH of the soil and some of the species do not like soils with high organic levels.
The ideal time to plant cypripediums is in the autumn thus allowing the rhizome time to acclimatize during the winter period. However, planting can take place in the early spring prior to the buds breaking. As indicated before, the choice of site is important. Find somewhere with the appropriate cool shady conditions and if possible where the ground is sloping so the rain will run off. Dig a hole some 20 cm deep and two to three times the width of the rhizome when laid out. If the soil is not clay then use that soil plus additives as suggested above. Hold the rhizome in the hole with the roots spread and the buds about 3 cm below the surface. Fill in the hole with the mix leaving a hump over the buds. Do not firm the area. To help protect the plant put 2 cm of sharp grit on top of the area. Some growers make up a mix without using any of the existing soil and plant the orchid in an aquatic basket which is then buried in the ground. Some species are best grown in a mix of pumice, perlite, grit and a small amount of leafmold.
During the winter some growers cover the plants with ridge tiles to keep off the winter rain. Depending on the winter temperatures, growth usually starts in late March; although hybrids with reginae as a parent are often later. It is wise to protect against slugs as there may not be a lot of other growing plants around.
The Cypripedium Growing Season
Immediately growth starts the plants should be fed. I use a mix of Tomerite and seaweed at ¼ suggested strength. Feeding should take place at 10 day intervals right through the season until a fortnight after the plant has become dormant. The later time is when the new root system is still growing and can absorb nutrients.
Cypripediums can also be successfully grown in large pots. This enables full cultural control at all times. Plants can be moved around according to the season. Winter rain protection becomes easy and pots can be put in a cool position in the summer.
The most important thing to remember is that pots will dry out. Always a pot at least 30 cm across and a similar depth. This will help in the winter when there are very heavy frosts. Whilst the rhizome will take frost from above , side frost will often damage the roots.
Because the plants are in pots they need more food that those in the ground and should be watered regularly in dry periods. Repotting should only be necessary every 4 or 5 years.
Source : http://lanesidehardyorchids.com/catalog/cypripedium.php