Giant sundews, with their captivating sticky tentacles, are unique carnivorous plants. Their glistening leaves, covered in mucilage that traps insects, make them a fascinating addition. These plants demonstrate a remarkable adaptation to nutrient-poor environments, relying on their carnivorous nature to supplement their nutritional needs.
Understanding Giant Sundews
The term “giant sundew” primarily refers to Drosera regia, also known as the “King Sundew” due to its substantial size. This species can produce individual leaves up to 70 cm (28 inches) in length, making it one of the largest sundews discovered. Its leaves are linear and lack petioles, tapering to a fine point, and are densely covered with stalked glands that secrete the characteristic sticky mucilage. These glands are capable of responding to trapped prey by bending to engulf the insect. While other large Drosera species exist, Drosera regia stands out for its unique characteristics and leaf dimensions.
Habitat and Natural Environment
Drosera regia is endemic to a single valley in the Bainskloof Range near Wellington, Western Cape, South Africa. It thrives at elevations between 500 to 900 meters (1600 to 3000 feet). Its natural habitat consists of fynbos vegetation, characterized by marshy grasses and low evergreen shrubs. They typically grow in permanently damp, well-drained soils, often peaty quartzite sand with a gravel cover, where water constantly seeps through. This environment provides a consistently cool root zone, even if air temperatures fluctuate. The climate is subtropical, with moderate temperatures and cooler nights, and the most significant rainfall occurring during winter.
Cultivating Giant Sundews
Successful cultivation of Drosera regia involves replicating its natural conditions. Understanding its needs can lead to vigorous growth. Unlike many other sundews, Drosera regia has distinct preferences that differ from typical carnivorous plant care.
Light Requirements
Giant sundews thrive with ample bright light to full sun exposure. Outdoors, they tolerate full sun, but protection from intense midday sun in hot climates may prevent root overheating. When grown indoors, bright grow lights are essential, providing 10-12 hours of light daily. Insufficient light can result in floppy, elongated, and less dewy leaves.
Watering Needs
Consistent moisture is important for Drosera regia, but the plant does not prefer sitting in stagnant water. Distilled water, rainwater, or reverse osmosis water are necessary, as tap water contains minerals that can harm the plant. While the tray method is common for many sundews, Drosera regia prefers constantly seeping, cool, pure water through well-drained substrate, suggesting good root aeration. Some growers allow the medium to dry slightly between waterings to ensure proper root aeration.
Soil and Potting
A light, airy, and well-draining soil mix is ideal for giant sundews. Common blends include peat moss mixed with a significant proportion of sand or perlite (often 50/50 or up to 75% perlite). Long-fibered sphagnum moss, either pure or mixed with perlite, is also a suitable medium. The use of fertilizers in the soil is avoided for most carnivorous plants, but Drosera regia is an exception that benefits from light soil fertilization once established. Tall pots are recommended to accommodate their extensive root systems, with mature plants benefiting from pots around 16 cm in diameter and 18 cm tall.
Temperature and Humidity
Drosera regia prefers moderate temperatures with a noticeable drop at night. Daytime temperatures of 15-29°C (60-85°F) are suitable, with nighttime temperatures ideally dropping to 10-20°C (50-68°F). Cooler nights can help offset warmer daytime conditions. While some humidity is beneficial, extremely high humidity is not necessary and may promote rot if the soil is waterlogged. Humidity levels between 50-75% are appropriate.
Feeding Your Plant
Giant sundews are robust growers with a significant appetite, requiring regular feeding to thrive. They can capture large prey such as beetles, moths, and butterflies with their highly responsive leaves. If grown outdoors, they will naturally catch insects. For indoor plants, feeding live insects like crickets or freeze-dried options such as bloodworms or fish food pellets is beneficial every 2-3 weeks. Foliar feeding with dilute liquid fertilizer can also supplement their diet.
Propagating Giant Sundews
Propagating Drosera regia can be achieved through several methods, with root cuttings often being the most effective. These methods allow growers to expand their collection or share these unique plants.
Root cuttings
Root cuttings are a reliable way to produce new plants. Segments of healthy, fleshy roots, about 1-2 cm (0.5-1 inch) long, can be placed on the surface of moist long-fibered sphagnum moss or a peat/sand mix. Covering the container to maintain high humidity helps, and placing them in a warm location can accelerate plantlet development. Plantlets typically emerge from the root segments within a few weeks.
Seed propagation
Seed propagation is also possible, and Drosera regia seeds are relatively large compared to other sundews, making them easier to handle. Seeds can be surface-sown on the same medium used for mature plants and germinate within 2-4 weeks without requiring stratification. Ensuring consistent moisture and warmth promotes successful germination.
Leaf cuttings
Leaf cuttings can also be attempted, although they may be more prone to rot before plantlets form. If using leaf cuttings, floating them in water or placing them on a moist medium in a high-humidity environment can yield results. Once plantlets form from any method, they should be transferred to a suitable moist medium to continue growing.
Troubleshooting Common Issues
Even with careful cultivation, giant sundews can encounter problems. Promptly addressing these issues helps maintain plant health.
A common concern is leaves losing their dew, which can indicate insufficient light, low humidity, or inadequate watering. Increasing light intensity, ensuring consistent moisture with appropriate water, and providing stable humidity can help restore dew production. Browning or blackening foliage, particularly at the tips, can be a sign of mineral buildup from tap water, excessive heat, or overly wet, anaerobic soil conditions. Flushing the soil with pure water, ensuring good drainage, and keeping roots cool can alleviate this.
Stunted growth often points to a lack of sufficient feeding or suboptimal growing conditions. Since Drosera regia is a heavy feeder, consistent provision of insects or appropriate fertilization is important for vigorous growth. Adjusting light, temperature, and soil conditions to match their preferences can also promote healthier development. Pest infestations, such as aphids, can sometimes occur. These can be managed by gently rinsing the plant with water, using insecticidal soap, or applying horticultural oils like neem oil, ensuring to dilute them properly to avoid harming the plant. Fungus gnats may also appear in consistently moist media; these can be controlled with biological methods such as Bacillus thuringiensis israelensis (Bti) in the water.