Wooly Sundew (Drosera) Cultivation
General Info:
Wooly Sundews (subgenus Lasiocephala, also called Petiolaris-complex Sundews) are uniquely aesthetic, rosetted sundews often covered in fuzzy white hair. There are over a dozen described species (and maybe another dozen undescribed) that vary from extremely fuzzy, narrow, green leaves, to wide, flat, red leaves. What they all have in common is their love of heat and humidity (and beautiful geometric shapes).
Among the varied species, most grow a few dozen thin leaves in a circular (and sometimes hemi-spherical) shape variable in color from a light blueish-green to dark red and varying in hairiness. Species like Drosera falconeri are unique with their extremely odd, wide lamina and are some of the coolest of all Drosera. Drosera paradoxa and can grow tall stems over time, some forms reaching a few feet in length. Drosera banksii can also grow a thin stem but is a uniquely annual species in the subgenus. Drosera caduca is one of the weirdest of all Sundews, as it is only a part-time carnivore. Part of the year it produces carnivorous leaves, but it will transition to producing leaves without the carnivorous lamina, instead looking like a grass!
Most species come from the monsoonal tropics of Northern Australia (a couple extend into New Guinea). The climate in this region can vary from hot, monsoonal rains to hot (slightly cooler), and dry with almost no rain. Given the distinct seasonality, the Wooly Sundews have evolved methods to survive the dry season with a dormancy and a covering of hairs to both protect from the sun and to collect moisture from the air. While many can retreat to a small bud in the dry season, they do not require this in cultivation and can be grown more-or-less year-round. If they do decide to go dormant (usually due to decreases in temperature), give them less water until they decide to wake up.
In general, the hairier species are more tolerant of less humidity and drier soils (Drosera derbyensis, Drosera lanata, Drosera ordensis, etc). The less hairy species prefer to be humid and wet constantly (Drosera fulva, Drosera falconeri, etc). Cultivation is straightforward with lowland tropical conditions including high humidity and intense light. If given the proper conditions, these plants are easy to grow. If given the wrong conditions, they can be prone to rot.
The flowers are mostly between white, pink, and purple, however there are rare forms with multicolored or orange blooms. Some species can produce comically long stalks with well over 100 consecutive flowers. The flowers are not self-fertile and require cross pollination to produce seed. Within my collection, I have crossed many species — some will readily product seed while others seem incompatible and never produce seed. In fact, most crosses seem to yield no seeds. This creates a challenge when propagating particular forms or location specific taxa. The plants will naturally divide over time, perhaps once or twice per year. These growth points can be split apart and grow into new clones of the mother plant.
Overall, these are excellent plants for indoor growing in terraria or heated grow tents and look beautiful under LED lights. The simplest setup is using a small terrarium or enclosed tray and putting in a seedling heat mat to provide constant heat. Another method is to add a few inches of water to an aquarium and use a simple aquarium heater to maintain warmth. Elevate the plants over the water.
Cultivation:
Lighting: Part to Full Sun or 20W per sq ft LED light. Strong light is essential for strong growth and survival. I don’t believe photoperiod has to change throughout the year, but I will cycle the lights from ~10-14 hours based on season.
Water: Distilled or Reverse Osmosis water. Sitting in 0.5”-1” of water using the tray method (depending on pot height). Some species like very wet conditions, while others prefer good drainage and less moisture. This roughly correlates to how hairy they are (hairier = drier). However, most are quite tolerant of wet conditions if given high temperatures and powerful light.
Climate: Temperatures from 70-100F and high humidity. These are best grown indoors in a heated terrarium or grow tent. I have not experimented growing these outdoors as winter temperatures would likely cause issues. I cycle the temperatures from the 70F’s to 90F’s everyday.
Soil: I am using 25% Peat: 30% Perlite: 45% Coarse Sand for the hairier species, 40% Peat: 40% Sand: 20% Perlite for the wetter growing species. Soak and rinse out the media before use as these species do not like minerals/humic acids. The exact mix is not as important as the resulting moisture levels in the pot which will vary based on watering.
Feeding: Feed leaves with Insect Powder every 2-4 weeks or more. Given the small surface area of the lamina (carnivorous area), I prefer to feed Insect Powder to most species. I will foliar feed Drosera falconeri and caduca with a dilute fertilizer.
Notes:
These grow beautifully under strong LEDs, and the heat of the LEDs can be used to warm their growing environment.
As peat breaks down, it produces tannins/humic acids. Give the occasional flush of the soil using distilled or reverse osmosis water if the water trays have a tea-color to water.
Plants can choose to shrink into a dormancy, at which point they should be kept drier until they decide to wake up.
Over time, the plants will sprout new growth points. These can be divided into separate plants.
More Information:
https://www.youtube.com/watch?v=UXpcvMmVs4M (an incredibly in depth explanation of Wooly Sundews by one of the world’s experts)
