I have been growing Pygmy Drosera for about 4 to 5 years, and have certainly learned a lot about this fascinating group of plants in that time. Not having the luxury of regularly seeing these plants in the wild increases my enthusiasm to grow them and I’m sure this applies to many of you as well.
When I first started growing CP’s I would follow the cultivation directions provided in CP books religiously. If the book said use this exact mix for Nepenthes, I would. As you would expect, many plants died because treating all plants within a single group alike is simply not the answer to successful growing. Some people tend to group plants according to origin, and treat species in that group the same way. While this method yields better results than the previous one, it is not always ideal.
So how does this relate to my experiences of cultivating Pygmy Drosera? It’s a common practice when growing these plants to sow seed or gemmae in a pot full of a standard 1/3 sand, 2/3 peat or perhaps a 50/50 mix. While it is true that there are hardy species which will grow in just about everything, many of the more sought after species don’t. From my experience, treating pygmy Drosera species on an individual basis is the way to good growing. While it is certainly more time consuming than potting up in a standard mix, you are far more likely to be successful. I choose to grow only Australian native CP’s (mainly Pygmies, but Tuberous Drosera as well), so using a different mix for each species is easy for me since my collection is not as large as some. Climate is an important factor, which I would love to be able to change for each species, but that is totally impractical. Perhaps if you have a large sum of money lying around, it might be easy! So as far as climate goes, all of my Pygmies are treated the same.
My plants are grown under a canopy of Solarweave, a woven PVC fabric which allows excellent light transmission, another most important factor when growing Pygmies, as the colour of the plants appears to be directly related to the amount of light they receive.
Now onto the good stuff, the facts that I think you need to know. While there is certainly no right and wrong mix to use, as you would expect, a mix as close to that of the plants natural habitat seems to give the best results. From my visits to Western Australia I have established that many species grow in fine white sand, and for most people this is easy enough to obtain. Species, which in nature grow in pure sand, will most definitely grow in sand of various sizes, but I tend to use a grain size that closely matches that of the natural conditions. This usually means the use of very fine sand. Apart from being more aesthetically pleasing to the eye, finer grained sands are usually more practical, for instance gemmae tends to strike better in a finer grained sand.
Sand is graded commercially by passing it through sieves that are numbered according to the openings per inch, e.g. 30/60 grade sand is the coarsest I use for Pygmy Drosera and the majority is much finer. I don’t normally purchase graded sand, I just select it by recognising that it is a fine grade and the colour I’m interested in obtaining.
Probably one of the hardest soils to find a substitute for, outside Western Australia, is laterite. Drosera barbigera in one species that grows in laterite, and many growers have reported it a difficult plant to keep going. After a couple of attempts at growing this species, I’ve finally had success. The mix I use is mostly red loam, with some fine (powdery yellow) sand and quartz chunks (which were already in the loam when I got it). Obviously it will be difficult for anyone to obtain the exact same sands I have used, so some experimentation will be required.
For more information on laterite see further articles in this section.
The use of small pots is okay for some species, mostly the plants preferring swampy areas, e.g. D. pulchella, D. enodes and some of the D. nitidula sub species and hybrids, which grow where the water level is much closer to the soil surface. For most Pygmies however, a large pot is beneficial. The bigger you can make it the better. I use pots ranging from 19cm to 27cm in height. Pygmies root are usually longer than you think.
Another benefit of big pots is the width of the pots. In most cases the plants growing in the middle of the pots are the largest and healthiest. The soil tends to heat up on the sides making it less than ideal for the plants to grow in. With a larger pot you have a much larger cool area in the middle for the plants to grow. On the down side it certainly makes it difficult to bring my plants along to the ACPS meetings since large pots of sand are very heavy.
Despite what I have said above about the grouping of plants, there are many Pygmies that grow in virtually identical conditions to others. They are listed under various sections because I have either found them in that particular soil type, or have seen photographs of them growing in that soil type, it is not generalization of what each species grows in. I have also tried and tested plants in these soils, with good results.
Plants found in white silica sands of various sizes:-
D. closterostigma – also does well in a very fine yellow sand.
D. nitidula ssp leucostigma
D. nitidula ssp allanostigma x ericksoniae – does better with some peat added.
D. nitidula ssp omissa
D. nitidula ssp omissa x pulchella
D. paleacea ssp paleacea
D. pulchella – does better in peaty sands as it is found in swampy areas.
D. pygmaea – prefers really fine grained sand.
Plants found in laterite soils (or my red loam sand mix):-
D. barbigera – red loam with fine sand.
D. lasiantha – red loam with small amounts of coarse white sand
D. sewelliae – red loam with small amounts of coarse white sand
D. silvicola– red loam with small amounts of coarse white sand
D. stelliflora – red loam with small amounts of coarse white sand
Plants found in swampy soils (various mixes of peat and different grades of sands)
D. ssp ‘Carbarup’ – prefers only a small amount of peat, mainly sand mix.
D. enodes – black peaty sand.
D. occidentalis ssp occidentalis
D. occidentalis ssp australis
There are of course other plants which are found in soil types not listed, such as D. mannii which is found in a clay-ish soil. This is more difficult to substitute since clay soil types are usually more complex, perhaps containing different amounts/types of sand, organic matter etc. Fortunately this species doesn’t mind a standard peat/sand mix. When potting up this year, I ran out of sand for some D. pulchella gemmae, so I put them in pure red loam to see what would happen. To my surprise they are the healthiest looking D. pulchella I have had.
When using sands, there are some things to be aware of. The obvious one is to do your mixing in an open area, and wet the sand, so there is no risk of particles flying around for you to breath in. When planting gemmae on pure sand, the soil surface tends to dry out quickly, so spraying with water every day or so is necessary until the plant sends a root into the soil.
Some sands also tend to produce a small salt build up in the soil surface. If in sufficient quantities it can kill plants. One way I have considered getting around this is to water from the top down, instead of the tray method. I have a few native terrestrial orchids growing in sandy mixes with a layer of old gum leaves on top, both to act as nourishment and to stop the sand going every where when I water them. This is certainly something I plan on trying next year on some Pygmy Drosera species. Obviously it is not suitable for all, but plants such as D. silvicola, D scorpioides and D. stelliflora can all be found growing in leaf litter in their natural habitats.
I have only covered a small amount of what can be done to grow Pygmy Droseramore successfully. I would advise anyone interested in this group of plants to try and do as much research as possible into their natural habitats and growing conditions. If possible, a visit to Western Australia to see plants in their natural environment is a must, and with the current rate of land clearance in Western Australia, some may not be there much longer. As I stated earlier, there is no right or wrong way to grow these plants, but by experimenting to find the best way reproducing their natural conditions you should be able to grow great plants.
Reproduced from the Australian Carnivorous Plants Society Bulletin Volume 18 – 4 With kind permission from the author.