This is one group of Pinguicula that can be grown outdoors with great success and they make an incredible addition to carnivorous bog gardens and containers; if you live within their natural range you shouldn't encounter any issues keeping these plants alive when you provide for their basic needs, which means that they may be an ideal Pinguicula group to explore when you are first starting with this fascinating genus. A great, often readily-available species to start with is Pinguicula grandiflora. To access the information on this page, please click on one of the topic titles below; to hide it again, simply click the title a second time. (Photo to the right courtesy of dimitar @ Flytrapcare.com)
Cold temperate Pinguicula seed benefits greatly from a period of cold stratification; stratification is a process that would occur naturally in the wild that greatly increases germination rates by gently preparing the seed over the colder months. While not required for all species, stratification can greatly boost the germination rate of the seed you wish to grow, so before you start sowing them it's worth exploring the two methods of replicating this process: natural and artificial.
Natural stratification involves sowing the seeds onto moist peat in pots and placing these outside in mid to late autumn; the natural drop in temperature does most of the work for you, all you need to do is check on the pots occasionally and water as required, while protecting them from the harshest snow and frost. Artificial stratification involves wrapping seeds in damp paper towels, popping them in a ziplock bag and placing them in the coldest part of your fridge for eight to twelve weeks; the seeds need temperatures between -10°C and 5°C (14°F and 40°F) for an extended period of time (8 – 12 weeks) to germinate.
Cold temperate Pinguicula usually prefer acidic soil so a peat/perlite/silica sand combination works very well; keep it moist (but not wet) at all times and never allow it to dry out. Keep an eye out for mould and fungus and carefully scrape this away with a toothpick if you encounter it.
As the seeds will have been sown in cold weather the photoperiod they encounter may vary considerably, you'll just have to wait and see what the weather throws at you. Seeds do not need light to germinate, so this is not a concern, but the newly exposed sprouts will need light – if you sow the seeds at the right time of year they should germinate just as light levels begin to increase so this shouldn't be a problem. If your seeds are sown in a sheltered location, it may be advisable to move them to a brighter area once the first sprouts appear.
These seeds can be sown and grown indoors without stratification but, as mentioned earlier, germination rates will likely not be as good. It's definitely recommended to either sow your seeds in pots placed outside over winter, if your climate permits, or germinate them in your fridge as outlined above.
It can take eight to twelve weeks for cold temperate Pinguicula seeds to germinate.
The intensity of sun you give your plant depends mostly on the temperature of their growing environment; if it is particularly warm, it's important to give your plants indirect or dappled sunlight, if the temperature is cooler however these plants are hardy and many can handle full sun for a number of hours each day.
If growing indoors on a windowsill that receives full sun, it is advisable to shade your plants during the hottest and brightest part of the day (particularly during summer) to prevent them drying out and experiencing issues. If the windowsill receives indirect or dappled light, you usually don't need to worry too much.
Most Pinguicula have very short roots so there are a wide variety of containers available for you to use. Cold temperate Pinguicula need to be kept very damp year-round so it's important that the container you use is deep enough to not dry out very quickly (the shallower the pot, the quicker the soil will dry out), so please keep that in mind when choosing a container. Plastic pots are usually very good for these plants, but black ones should either be painted white or avoided because they absorb heat. Insulated cups are also great choices for these plants.
Your cold temperate Pinguicula soil mixture will degrade over time and compact, this can cause problems for your plants in the long-term if left unattended for a long period of time as compacting creates a good environment for rot. To prevent this, you can re-pot your plant once every one to two years by gently removing the plant from its pot, replacing the soil with fresh mix and re-planting the plant. Removing old soil from the roots is advisable but not required, don't worry if the odd root here or there snaps or breaks off entirely, as long as there are other roots your plant will be fine.
To avoid damaging roots, you can re-pot your plant while it is in its winter hibernacula (please see “winter care” section for more information).
Typically, cold temperate Pinguciula prefer acidic soil that is water retentive, so peat or sphagnum moss are ideal components in your soil mixture; combining these with silica sand or perlite will increase drainage and help oxygen to permeate the soil, reducing the risk of rot and fungus taking hold while increasing the longevity of your soil mix (so you won't need to re-pot your plants as frequently). Depending on your climate, you may want to add more or less aeration to your soil.
Please make sure all potting components are free of fertilizers and wetting agents as these are usually deadly to Pinguicula. When dealing with perlite and vermiculite, please ensure that you dampen them before use and avoid breathing in the dust as this is dangerous.
Cold temperate Pinguicula, as their name suggests, come form locations in the northern hemisphere that have cold winters and mild summers with cool winter nights, therefore it is important to give your plants these conditions yourself. They are not the most heat tolerant plants but can handle higher temperatures as long as they are watered well and experience cool nights.
You can help your plants to cope with particularly warm weather by shading them during hot days and watering with cool water; avoid terrarium environments at all costs because these are not terrarium plants.
Mineral free water is a must for these Pinguicula as they are not designed to handle the mineral content of most tap water sources. Most species in this category prefer to be kept moist (but not wet) year-round and are more resistant to root rot than others of their kin; in hot weather, with bright sunlight, it is very important to ensure your plants are receiving enough water as if they dry out if could kill them very quickly.
Cold temperate Pinguicula require what is sometimes referred to as a wet dormancy; for those of you who grow Dionaea muscipula (Venus fly traps) this process of dormancy is somewhat similar: to induce a wet dormancy you gradually reduce photoperiod (light exposure), prey and temperatures. Sudden changes to any of these (with the exception of prey) can cause the plants to go into shock which can be fatal.
Photoperiod and temperature should gradually decrease naturally in the autumn, which will be the cue for your plant to change its growing habits, it won't stop growing but instead will transform into a vegetative bulb known as a hibernacula; these fascinating looking bulbs are frost and snow resistant. It is imperative that you keep your cold temperate Pinguicula in a cool place during autumn and winter but don't allow them to freeze.
It is advisable that you keep your plants moist during winter; water evaporation levels should decrease naturally as the year progresses, so you will likely find that you don't need to water your plants quite as much. Too much water with cold temperatures and low air movement can cause mould and fungus to occur, so it's important to keep an eye on your plants and avoid over-watering. Please make sure your plants never dry out as this could be fatal.
In early to mid spring your Pinguicula should begin to grow carnivorous laves again, these will sprout from the centre of the hibernacula. It is entirely possible that your plant may flower before it has completely emerged. It is also common for cold temperate Pinguicula to produce gemmae at the base of their hibernacula after a successful dormancy – these will look like miniature versions of the adult bulb. These buds can be carefully removed and planted where they will burst into life themselves once light and temperatures increase over the course of spring.
If given the right conditions, gemmae can grow very quickly and you may find yourself with a mature plant by mid to late summer of the same year!