Subtropical Sundew (Drosera) Cultivation
General Info:
Subtropical Sundews (genus: Drosera) are a type of carnivorous plant that uses sticky tentacle covered leaves to trap and digest insects. Sundews are capable of curling their tentacles (and some can curl the leaf as well) in response to food, securing the prey and bringing it closer to the leaf for digestion. While there are over 200 species of Sundews, the Subtropical Sundews are a loosely defined group that has no strict dormancy period and prefers to stay above freezing. They grow best in mild temperatures between 50-90F compared to Lowland Tropical Sundews that prefer consistently hot temperatures between 70-100F. I also distinguish them from Highland Tropical Sundews which live in high elevation cloud forest in the tropics and prefer high humidity plus consistent temperature fluctuations between around 55-80F and suffer at hotter temperatures or low humidity. Subtropical sundews can tolerate low to high humidity and temperatures between 30-100F and have no dormancy requirements.
Many Subtropical Sundews come from the biodiversity hotspot of South Africa which includes the popular species Drosera capensis, Drosera aliciae, Drosera nidiformis, etc. They will grow great outdoors in most mild climates and also love powerful LED lights indoors. Overall, quite simple and easy to grow, though some species are more sensitive to extreme heat than others. Most species will readily self-pollinate to produce seeds that are easy to grow.
Growing Subtropical Sundews is very easy with bright light. Make sure to give them at least a few hours of sunlight per day or 20W/square foot of high quality LED grow light. The tentacles will turn red in good light (except for all green varieties). Feed them regularly to stimulate fast and vigorous growth. For watering, use distilled, reverse osmosis, or rainwater and keep them in a shallow tray of water. The soil should always be moist. They can tolerate quite wet conditions, or temporary dryness if grown in strong light. These are forgiving plants that are great for beginners.
Cultivation:
Moderate to high Light - give them a few hours of sunlight per day or at least 15-20W per square foot of LED grow lights. The more light, the more colorful the leaves.
Water using the tray method, keeping the pots sitting in 0.5-1” of water. Most of these species can tolerate a dry tray (but still moist soil) for a while before showing stress.
Temperatures between 50-90F are best, but they will do fine at 40-100F. Frost will cause them to die back to the roots, but most species will recover and regrow.
Many soil mixes will work, the most common being 50% peat moss, 50% perlite/sand.
Notes:
I use the term subtropical quite loosely as many of these species grow in “Mediterranean” habitats, but with consistent sources of water. I group species that can handle a wide temperature range, low humidity, and have no dormancy requirements into this group.
Feed them by applying dry fish food powder to the leaves every few weeks. Feed only dewy leaves.
Frost can cause many of these species to die back to the roots, but they will recover in spring and regrow.
Most of these species can grow new plantlets from leaf cuttings and roots.
More Information:
https://www.carnivorousplants.org/grow/guides/SubtropicalDrosera