Mexican Pinguicula have two growth states: summer and winter. In the summer they display carnivorous leaves which produce the mucus that lures, traps and digests insects whereas in winter they grow non-carnivorous leaves, which differ in shape and size, as well as number; these succulent leaves stack on top of each other, believed to protect the plant from cold.
The vast number of Mexican Pinguicula species originate from Mexico but a small number of species can also be found in Guatemala, Cuba and Belize. Currently it is estimated that there are at least 46 individual species available in cultivation, with countless hybrids and flower/colour variations. 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.
For the most part growing Mexican Pinguicula from seed is easy, it simply requires a little preparation and a lot of patience. Seedlings are more demanding than adult plants so if you are new to Mexican Pinguicula I would advise having a go at growing an adult plant first to give you a general “feel” for the plants' needs; once you feel you are ready for the challenge of growing from seed, I hope the information below will help you to achieve success. Please make sure you research your individual species before sowing any seeds to ensure your conditions are optimal.
It is important to choose the right growing media when sowing your seeds; any mix that retains water well will be fine, and you can sift the top centimetre or half inch of the soil to make it easier for new roots to penetrate. Please only sow seeds on the surface of the soil and do not bury them.
I have read of cases where people have successfully germinated Mexican Pinguicula seeds on pure perlite, but have not tried this myself. I have had success using dead, chopped sphagnum moss (although this is highly water retentive). I do not advise peat-based mixes as peat can create an ideal environment for fungus gnat larvae, which will decimate young plants. If attempting to grow purely on perlite, you can line the bottom of your growing container with sphagnum moss to act as a water wick, which will suck the water up, store it, then distribute it through the perlite, but keep in mind that this is not a necessity by any means.
The seeds will need temperatures between 15°C – 25°C (60°F – 80°F) to germinate well (consistency matters as much as anything else), and should be kept damp but not wet. It is important that you do not allow your seeds/seedlings to dry out between waterings as this will be deadly for such young plants. Please also only use pure water; watering via a tray will be much easier and less dangerous for the seedlings than watering from the top of the container, which can cause seeds to sink and get lost. Elevated humidity will be beneficial but is not a necessity. A heated propagator is ideal for initial germination, but please do not sit one of these in direct sun as it will cook the inside of the container due to the plastic lid.
If keeping your seeds/seedlings in a humidity dome, it is important that you air it daily to prevent mould and fungus from occurring. It is also important that you gradually acclimatise the plants to the relative humidity of your growing area, outside of the dome, gradually as not doing so can damage the plants temporarily.
Seeds themselves do not actually need light to germinate, but artificial/supplemented lighting will be greatly beneficial once the first leaves appear. If it is a warm time of year, you may be able to keep your container on a windowsill and it should receive sufficient light, but oftentimes it is advised to use artificial lighting for the initial germination process and the early days.
If all goes well, you should expect to see your first sprouts within two to eight weeks, although it can take a little longer if the seeds are particularly old. Refrigerating unused seeds will help to keep them fresh if you are not ready to sow an entire packet.
All plants need sunlight, for Mexican Pinguicula more is better, however please provide some form of protection (perhaps in the form of a shade cloth) if your plants are kept in full sun so as to prevent leaf scorching. Bright, indirect sunlight for most of the day (at least 10 hours during the spring/summer) is ideal and can often be achieved on a south-facing windowsill, although an east or west will usually suffice.
Artificial lighting can also be used however as I do not have any long-term experience with this I cannot provide you with in-depth information.
You may notice that, as your plants experience bright light, their colour starts to change. First, the leaves may go from a medium shade of green to a very light, almost white shade, and then gentle hues of pink, purple or red may come through – this is completely natural and is an utterly astonishing secret in Mexican Pinguicula! The colours that these plants can develop in artificial lighting, in particular, are gorgeous. Even on a windowsill, some species (P. cyclosecta, for instance) can produce surprisingly vibrant, exotic colourings.
Most Pinguicula have very short roots, so you can use a wide variety of pots and containers to display your plants. Please be aware that a deeper pot will likely retain moisture for longer, so this can be beneficial if you come from a hot climate, but shorter pots do have their merits and are useful during the winter months. I use a small, modified plant tray that is about an inch deep for some plants, but I grow others on a piece of tufa, which is a kind of limestone often used in aquariums, but I have also used a variety of plastic pots and decorative containers.
You are free to use your discretion when choosing a planting container for your Mexican Pinguicula, although something at least 5cm deep will help with water retention, although it means that you'll need more growing medium. If you are growing your plants in an organic medium (that contains peat or sphagnum moss), I always advise growing them individually rather than together, but if using a purely mineral based medium you can grow many different plants in one container without much concern; I say this because I've had most trouble using organic substances and if multiple plants are kept together, the problem can spread very quickly.
If your soil mixture contains peat or sphagnum moss, it will degrade over time and compact; this will reduce the airiness of your soil and may cause problems for your plants, so it is important to re-pot your plants once every one to two years. Thankfully re-potting Mexican Pinguicula is very easy and simply requires you to gently remove the plant from its current container, get as much soil off its roots as possible and gently position it in the container with fresh soil (you don't have to change the pot each time you re-pot unless the plant has outgrown it); you may find you have to “wriggle” the plant a little bit to get the roots to sit under the surface of the soil, but as long as you are gentle this isn't a concern.
If your plant loses any leaves while re-potting, don't panic! You can simply sit these on the surface of a container of growing medium, keep them slightly moist and you might see new plants growing from the leaf base.
Unlike most carnivorous plants, Mexican Pinguicula actually prefer an airy, slightly alkaline growing media and can handle much higher levels of nutrients within their soil. In their natural environment, many of these plants will grow in the cracks and crevices of rock walls, with their roots kept damp by an abundance of air moisture and rainfall as it descends down the cliff faces.
Peat, perlite, silica sand, pumice, vermiculite, lava rock and tufa are all fine to use with Mexican Pinguicula; there seems to be an increasing number of people cultivating these plants in nutrient rich composts and aquatic soils (carefully balanced with enough aeration), so it would seem experimentation is possible. I've grown my own Mexican Pinguicula in a variety of organic and inorganic mixes, including a nicely airy peat mix, pure perlite, tufa rock and, most recently, a purely mineral mix composed of silica sand (two grain sizes) and coral gravel.
It is quite easy to over-think this element of Mexican Pinguicula care, but ultimately you need a simple mix that works for your environment. High humidity? Make it airier. Dry air? Give it a little more water retentiveness. These plants are somewhat more prone to rot than other Pinguicula, so it is important to consider this when determining what soil mixture you want to use. You'll ideally need something very airy, but that has water retention properties so it doesn't dry out too much too quickly. Granted, these plants are highly drought resistant, but during the summer months you need to make sure your soil can keep them hydrated.
Please be careful when dealing with perlite and vermiculite; the dust they produce can be quite dangerous so please wear an appropriate mask or dampen the product before use.
P. acuminata, P. agnata, P. calderoniae, P. clivorum, P. colimensis, P. conzattii, P. crassifolia, P. cyclosecta, P. debbertiana, P. ehlersiae, P. elizabethiae, P. esseriana, P. gigantea, P. gracilis, P. greenwoodii, P. gypsicola, P. hemiepiphytica, P. heterophylla, P. ibarrae, P. imitatrix, P. immaculata, P. infundibuliformis, P. jackii, P. jaraguana, P. jaumavensis, P. kondoi, P. laueana, P. laxifolia, P. lilacina, P. macrophylla, P. martinezzi, P. mirandae, P. moctezumae, P. moranensis, P. nivalis, P. oblongiloba, P. parvifolia, P. pilosa, P. potosiensis, P. rectifolia, P. reticulata, P. rotundiflora, P. sharpii, P. takakii, P. zecheri
These Pinguicula grow wonderfully in a range of temperatures as long as they are kept warm during their summer growth; room temperature (averaging 20°C) is absolutely fine for this species, their optimum range is 20-25°C (68-77°F), but they can handle temperatures as high as 45°C as long night-time temperatures are reasonably cool.
These plants were not made to handle frosts and snow, although their succulent leaves can withstand the cool temperatures windowsills would experience in the winter in a place such as England; I keep mine on my bedroom windowsill year-round and have done so for years without difficulty. On the coldest of nights I keep my small bedroom window closed so as to prevent freezing, tumbling cold pouring down onto the plants. Poorly glazed windows will allow more cold in, so this is something to keep an eye on.
It is important to avoid rapid rises and drops in temperature as these can cause health issues for the plants; consistency is better: room temperature during the day, cooler at night. External heating should not be necessary.
Pure water (mineral free water) is important as these plants were not designed to handle high quantities of minerals in their water, although they seem to be more forgiving than other carnivorous plants. An occasional watering with tap water in an emergency will not harm the plants in the long-term, however prolonged exposure to abnormally high minerals can harm the roots of the plant.
You'll likely need to experiment a little to find an ideal watering schedule for your part of the world; relative humidity, temperature and photoperiod will all affect the frequency you need to water your plants, as will where they are kept and what type of soil mixture they are in. The best thing you can really do is try to keep them damp (but not quite moist) during spring and summer, allowing them to dry out for a day or two between waterings, and then in the autumn and winter, when they are due to enter their winter dry state (more information available later on in the guide) you can let them dry out for a while longer.
Please do not keep your Mexican Pinguicula sat in water all the time as this encourages the environment in which rot can take hold; the easiest way I've found to water my own plants is to fill a small dish or tray with some water and then sit the container in there. Once the water has been absorbed, or after a day or so (whichever comes first), I remove them from the tray.
During the cooler months of the year, Mexican Pinguicula produce succulent leaves instead of carnivorous ones; these leaves do not produce mucus and are designed to protect the plant from the cold. This is a completely natural process that should ideally be replicated annually to allow the plants to maintain their natural cycle, as it has been observed that skipping the “winter dry season” can weaken the plant and make it more susceptible to rot, as well as cause unviable seed production. In worst case scenarios, some have reported that their Mexican Pinguicula have actually perished.
For the most part it's incredibly easy and simple to induce this change in leaf growth if you grow your plants on a windowsill. Photoperiod, moisture and prey levels all have key roles to play and two of these - photoperiod and prey - decrease naturally in the autumn anyway, all you need to do is gently reduce the frequency that you water your plants. I eventually find that I water my plants very infrequently over winter, but the frequency does depend a lot on air humidity and the temperature of your growing area. If the humidity is high, you don't need to water as much, if the temperature is high but humidity low, you may want to water a little more frequently – whatever you do, it's generally a good practice to allow your plants to dry out between each watering for a number of days.
If growing your plants under artificial lighting, you can replicate autumn (and then winter) by simply reducing the length of time the lights are on for; if you grow other plants alongside Mexican Pinguicula that need the same length of photoperiod throughout the year, moving your Pinguicula pots to a windowsill just for the winter dry is a good compromise.
Temperature likely has a minor role to play in encouraging a Mexican Pinguicula to produce its succulent leaves, but if your plants are kept on a windowsill and your climate experiences some kind of autumn or winter, then this shouldn't be a problem. Dramatic drops in temperature should be avoided as this can be harmful to the plants.
To encourage your plants to produce carnivorous leaves again in the spring, simply reverse this process: gradually and gently increase photoperiod, moisture and prey levels.
A good general timeline for the winter dry season, if you are in the northern hemisphere, is that is lasts from Halloween to Valentine's Day (so late October to mid-February). For the southern hemisphere, mid to late March until late July might be a basic guideline, but ultimately this all depends on where in the world you are from. If you take cues from nature, you can't go far wrong.