Tropical Sundew Care
Drosera is the genus of Sundews, containing almost 200 species, making it one of the largest genera of carnivorous plants. They all have similar traits, but are extremely varied in shape and size, some as small as a dime, others the size of a shrub. Some have small, circular leaves, others are long and spear-like, others still are forked. Some have white flowers, others have dark red ones. All sundews grow from rosettes, and have tentacled leaves. At the end of these mobile tentacles, there are glands that produce sticky mucilage that helps to capture and digest their prey. Mobility ranges from species to species, some only move their tentacles, others will tie themselves in knots to capture their prey. There are several different types of sundew growth habits and care. Temperate sundew, like Drosera binata and D. filiformis, can follow the same care instructions as that of a Venus flytrap or American pitcher plant which can be found here. Temperate species require a dormant period in the colder months, which can be found here. Today, we are focusing on tropical sundew care.
Habitat
Most sundew grow in similar areas, bogs, fens, seeps, or other sunny, wet locations with nutrient poor soils. This is not the case for all sundew, but most that you will come across such as Drosera capensis, and its cultivars like 'Mini Red' and 'Dark Maroon', Drosera spathulata, or D. hamiltonii. This is, by no means, a comprehensive list of tropical sundew! Nor is it a be all, end all for habitat type and distribution. There are exceptions to every rule in nature, though this is the most common. The key parts to take note of in these habitats are the sunlight and the soil nutrient quality. There aren't many tall plants in any of the wetlands listed, meaning these guys want as much sun as you can give them. They require full sun, at least 6 hours of direct sunlight. The soil in these locations are so wet that, depending on the specific habitat, there may not be true solid ground. This amount of water often washes away nutrients. But how do you replicate these unique growing conditions at home?
Lighting
For any bog-dwelling species, the plants require full sun, 6+ hours of direct sunlight. This can be a bit intimidating at times. During the warmer months, your tropical sundews can be grown outdoors, so long as they are placed in an area with enough sunlight. But these plants cannot tolerate our winters, and should be brought indoors if the temperatures are going below 50F. Inside, the brightest window in the house may be sufficient, but this can be hard to come by in the city. Keep an eye on your plant. If the red begins to fade and the plants lean more green, consider brightening the area. Grow lights are a great way to do this. All grow lights are different, so be sure to follow the directions that come with them for how to hook them up, how far to place them from your plants, and other safety features. Many growers opt for a 12 hour on/off cycle for their lights. Others turn the lights on when they wake up, and off before bed. Plants grown at Cedar Bridge Botanicals are grown under 12 or more hours of light when placed under artificial grow lights.
Watering
Water is one of the most important aspects of carnivorous plant care and where most people go wrong. Other plants can tolerate even the hardest of tap water, but carnivorous plants have an allergy. Plants became carnivorous because where they grow in nature, whether it is in a rainforest, bog, seep, or wet cliff face, their substrate is nutrient poor. With little to no nutrients in the soil, they had to find the energy they need to grow somewhere else. With this nutrient poor soil, their roots became extremely sensitive to mineral content, especially that which can be found in tap, well, and spring water. Even bottled drinking water isn't safe for them, often the label will state "minerals added for taste." The only safe waters to use with carnivorous plants are rain, distilled, or reverse osmosis water. You can also use water that is accumulated from a dehumidifier. All of these water types will have zero minerals or other dissolved solids in them. Filtered water often isn't filtered enough. Brita filters and most filters that come with your fridge are still leaving behind too many particulates. The only filter that is trustworthy is the Zero water filter. Leaving water out on the counter for a day will not make the water safer for carnivores, it will only make the mineral content more concentrated as they are left behind while the water evaporates. Using a TDS (Total Dissolved Solids) meter will help you to determine if your water is safe to use for the plants. Aim for 0, but anything below 50 is acceptable.
Drosera should be kept boggy, like the areas they grow in naturally. This is easiest when kept in a plastic or glass dish or tray, and keep that tray filled with the safe waters. Do not allow soil to dry.
Soil
Soil is another important aspect that is influenced by the sensitivity of the roots. They require soil with little to no nutrients. Regular potting soil has fertilizers infused into the soils and will burn the roots and kill your plant. The Carnivorous Plant Soil listed here is designed to suit a variety of carnivorous plants and is what the sundews are grown in here. There are ways to grow sundew without the use of traditional soil. Many growers prefer to use dried or live sphagnum moss, both of which hold onto moisture more than carnivorous plant soil. With live sphagnum moss, the moss will continue to grow at a slow pace. This does have the potential to overtake plants in pots, but is easily controlled with either a pair of snips or a strong pinch. Keep an eye to make sure the crown of your plants, or the center of the rosettes, are not submerged in moss, as this can cause rot.
Pots
Going along with soil, pots that carnivorous plants are grown in must also be low nutrient. That may be strange to think of, but terra cotta, unglazed ceramic, and metal pots can leach their nutrients into your nutrient free soil and slowly kill your plants. Safe plant pot materials include plastic, glass, or fully glazed ceramic- no exposed clay. Pot height is not crucial, but many growers will default to tall pots.
Fertilizing or Feeding
It is not recommended for new carnivorous plant growers to use fertilizers on their plants. Fertilizing is tricky and can lead to plant death if done incorrectly. If grown outdoors, your plants will catch their own foods. Feeding your plant is a safer way to provide nutrients without as much risk of causing harm to your plants. Many prefer fish food or freeze dried blood worms placed on the tentacled leaves once or twice monthly. If you happen to have reptiles who eat fruit flies, you can also feed some of these or other small insects to your plants. 14 day old crickets are small enough, but 1/4 inch crickets will likely escape the sticky leaves. Do not apply a large amount of food, live or dried, or molding can occur. This is the most similar to the plants catching their own food in the wild. Heavily diluted liquid fertilizers can be applied to the leaves and the leaves only, but it is not recommended for beginner growers.
It may seem like there are a lot of instructions and rules to take care of carnivorous plants, but they are truly easy to care for once you know all of their requirements. They are easier to care for than a pet, and, in some cases, easier to care for than other plants! Tropical sundews are great beginner plants in general, not just beginner carnivorous plants. If you have any questions or are worried about your plant in any way, shoot an email with some photos to cedarbridgebotanicals@gmail.com. The more photos and information on care you have been providing, the easier I can help!
Happy growing!
<3 Gina