Butterworts (Pinguicula) are carnivorous plants with attractive, sticky leaves, which are covered in tiny, glistening glands that secrete a mucilaginous substance to trap small insects. Their ability to capture prey, combined with vibrant foliage and delicate flowers, makes them a captivating addition to any plant collection.
Light, Temperature, and Humidity
Butterworts thrive in bright, indirect light. An east-facing window provides gentle morning sun, while south or west-facing windows may need filtering to prevent scorching. Under artificial lights, a 14-16 hour daily photoperiod with appropriate intensity encourages vibrant coloration.
Temperature requirements vary by origin. Mexican and tropical species prefer 55-85°F (13-29°C) and can tolerate higher temperatures if the substrate remains moist and they are not in direct, intense sunlight. Temperate species require cooler conditions and may tolerate light frosts.
Butterworts tolerate a range of humidity, but good air circulation prevents fungal issues. Mexican butterworts thrive in drier climates and do not require high humidity, though 40-80% is suitable. Avoid misting, which can cause crown rot or wash off the sticky dew; instead, provide consistent substrate moisture.
Watering and Substrate
Watering is crucial for butterwort health, as they are sensitive to minerals in tap water. Use only distilled, reverse osmosis (RO), or rainwater, as these sources are free from dissolved salts and minerals that harm the plant. Total dissolved solids (TDS) in the water should be less than 100 ppm, with less than 20 ppm being ideal.
Many butterwort species benefit from the “tray method.” Place the potted plant in a shallow saucer with 0.25 to 1 inch of purified water, allowing the substrate to wick up moisture.
Temperate species prefer consistently wet conditions, while Mexican butterworts can tolerate the tray drying out between waterings, especially during their non-carnivorous, succulent phase. Avoid top watering to prevent rot and soil disturbance, except for bog-dwelling butterworts.
Butterwort substrate must be nutrient-poor and offer excellent drainage. Standard potting soil, containing fertilizers and compacting, will harm these plants. A common mix for many species, especially Mexican butterworts, includes equal parts peat moss, perlite, and sand, or vermiculite and pumice. The mix must allow roots to breathe while remaining consistently moist but not waterlogged.
Feeding Butterworts
Butterworts capture small insects using sticky mucilage on their leaves, secreting digestive enzymes to absorb nutrients. Manual feeding is often unnecessary for outdoor plants or those with a natural supply of gnats and other small flying insects. They efficiently catch their own food, including fungus gnats and fruit flies.
If an indoor butterwort lacks sufficient prey, supplemental feeding promotes robust growth and flowering. Place small insects like wingless fruit flies, rehydrated freeze-dried bloodworms, or a tiny pinch of fish food on a sticky leaf every two to three weeks. Avoid overfeeding, which can cause rot or mold. Do not use human food or chemical fertilizers, as these damage the plant.
Understanding Dormancy
Many butterwort species, especially temperate ones, undergo dormancy. This resting phase is triggered by cooler temperatures and shorter daylight hours, occurring in winter. During dormancy, temperate butterworts form a hibernaculum, a compact, non-carnivorous bud of tightly packed leaves, which helps them survive cold.
During dormancy, reduce watering, keeping the soil drier but not desiccated, and provide cooler temperatures. Mexican and tropical butterworts exhibit a “succulent phase” during winter or drought, forming smaller, thicker, non-carnivorous leaves. They benefit from reduced watering during this time. Light changes, rather than moisture, cue the plant to transition between carnivorous and succulent leaf forms.
Troubleshooting Common Problems
Common issues signal an environmental imbalance. If leaves lose stickiness or appear stretched and pale green, it indicates insufficient light. Increase light exposure by moving the plant or using supplemental grow lights to restore vibrant color and mucilage production. However, direct, intense sunlight can cause leaf browning or scorching.
Browning leaf tips or a general decline in plant health, including yellowing or wilting leaves, link to water quality or improper watering. Mineral accumulation from tap water poisons the plant, so distilled, RO, or rainwater is essential. Overwatering causes soggy soil and root rot, while underwatering leads to limp or droopy appearances. Ensure the substrate is moist but not saturated, allowing some Mexican species to dry slightly between waterings. If the plant shows distress, check soil moisture and water purity.