Over the past couple of years I have become somewhat obsessed with hardy orchids and as I've experienced some success I thought it was time to branch out into new territory.
I have written about Dactylorhiza species in previous posts and following on from this I have decided to dedicate a post to my most recent endeavor. I am attempting to grow Cypripedium calceolus from newly deflasked seedlings.
I have chosen to grow Cypripedium seedling's as opposed to mature plants for two reasons. Mature specimens prove to be rather expensive. A single plant can cost anywhere upwards of £30. I also prefer to know that the plants I am buying are not supporting an illegal practice. Many plants are taken from the wild and as these plants are very rare native wildflowers I would hate to think I could be complicit in this awful crime against our landscape.
When growing seedlings of typical garden plants the process is fairly easy and although some extra care is sometimes required at certain growth points the cultivation of Cypripedium seedlings is a different kettle of fish altogether! The seedlings I have bought come from a sterile environment, known as a "flask", and as a result planting directly into compost or soil is not possible. Seedlings need to acclimatise to the outside world and compared to the flask this world is rather hostile and filled with danger.
Specialist substrates are essential in the cultivation of these seedlings. I use a mix of Perlite and Seramis, although I'm sure you can use other substrates such as vulca. Perlite acts to improve drainage, whereas Seramis holds on to nutrients and water. It is very important that organic matter is not introduced to the mix as this can promote mold which inevitably results in the death of seedlings. A period of exposure to cold temperature is also necessary to break dormancy. This process of vernalistation takes place over three months and ideally plants should be kept at a temperature below 5 degrees celsius during this time but should not be allowed to freeze. A slow release fertiliser should be added to the substrate to aid plant development.
I placed five seedlings into terracotta pots which have been treated as discussed above. All five have now come through dormancy and are starting to leaf out. I chose to leave the seedlings outdoors over winter and this was sufficient to break bud dormancy. It may be advisable however, to place seedlings in refrigeration to complete this process.
Siting is also quite important. These plants require a shady environment and need shelter from the midday sun. Roots need to be firmed in but also need the freedom to run, so a fairly loose but moist substrate is preferable.
Following a successful first year outside of the flask seedlings can be planted into organic substrates used for mature specimens, however, I have a while until I can do this.
Wish me luck!