Adventures in Drosera species: Pygmy Sundew
Some of the most wonderful droserae in the world are the pygmy species. Native to Australia and New Zealand, these tiny plants are probably the most powerful and prolific of the entire genus. They are adapted to survive the brutal Australian summers, where their habitat substrates bake like clay in the summer sun. To survive, they have evolved some strategies. In the winter, when they begin to grow, they produce gemmae: small hard reproductive bodies which form in the center of the cone like stipules, like little green eggs in a nest of fine hairs. They look like green seeds, but there is an important difference: these gemmae are exact clones of the parent plant, whereas seed is produced by sexual reproduction. Easily dislodged with the first rains of the wet season, they are propelled out of their “nests”, and can quickly repopulate a habitat, even if 90% of the population was killed off in the summer heat. The ones that survive do so by the formation of extremely long, thin, hair-like roots, sometimes reaching down a meter to whatever reserves of moisture are available in the summer. The gemmae have a high rate of survival success, far more than seeds, and they grow at a much faster rate given wet, cool conditions and good humidity. The process of gemmae formation is initiated by short day length and the above conditions.
(A note to growers: gemmae production will be inhibited if any light reaches the plants after sunset.) The pygmy species can tolerate a wide range of temperatures, but they prefer cool conditions, and many withstand temperatures close to freezing and even occasional light frosts. After the gemmae form into plants, they grow through the winter and flower the next spring. The plants are generally sterile, having evolved stable characteristics, and the clonal nature of their reproduction ensures that they will not lose a “good plan” by random recombination of genes. They require different clones to form fertile seed. The flowers are beautiful and prolific, and the plants bloom continually from spring to early fall. There is a definite summer rest period, and in habitat, a true dormancy. (Most species will forego the dormancy, and this should be encouraged in cultivation, as losses are high during dormancy).
Like all droserae, they require nutrient and salt deficient substrates. For cultivation, good mix is 70/40 washed silica sand and peat. Some growers have stated old peat is superior for good growth, and there is speculation of mycorhizal associations enhanced by aged peat. Drosera pulchella and its hybrids differ from most by a preference for more peat: 50/50. In cultivation, the plants should be grown in as deep a pot as possible, although most will grow fairly well in 4 inch pots. The plants do not mind close proximity with each other. These sit in pure water, rain or distilled, from winter to late spring, which supports gemmae development and early rapid growth, and then are allowed to dry slightly, but not enough to trigger dormancy (there are of course exceptions to this rule of thumb). In early fall, when new growth is noticed in the now mature plants, the pots are returned to the former schedule. Since these plants are light hungry, and cool growing, they are not r