The california pitcher plant (Darlingtonia californica) is a carnivorous species found only in California and Oregon. Insects trapped in the “pitcher” liquid get slowly digested. California pitcher plants are unusual among pitcher plants in that they produce their own fluid to trap insects rather than relying on rainfall.
I. Appearance and Characteristics
Darlingtonia californica —also called the California pitcher plant, the Oregon pitcher plant, cobra lily or cobra plant—is a species of carnivorous plant in the new world pitcher plant family, Sarraceniaceae. It is the sole species within its monotypic genus, Darlingtonia. The cobra lily is native to Northern California and Oregon, in the western United States, where the climate—while typically thought of as cool and humid—may be quite arid for many months of the year, more so than many carnivorous or pitcher plant genera could feasibly survive (such as Heliamphora, Nepenthes or Sarracenia). However, the cobra lily has evolved into life along the West Coast and in the lower Pacific Northwest through its carnivorous adaptations, where it may be found near bogs, vernal pools, on forested rocky slopes (near snowmelt, especially), creeks, or near seeps with cold running water, usually on serpentine soils. It has even been observed growing in drainage ditches or on the sides of roads. Despite being fairly commonly cultivated, Darlingtonia is designated as uncommon due to its rarity in the field.
The name “cobra lily” stems from the resemblance of its tubular leaves to a rearing cobra, complete with a forked leaf – ranging from yellow to purplish-green – that resemble fangs or a serpent’s tongue.
The plant was discovered during the Wilkes Expedition of 1841 by botanist William D. Brackenridge at Mount Shasta, Northern California. In 1853, it was described by John Torrey, naming the genus Darlingtonia after Philadelphian botanist William Darlington (1782–1863).
Cultivation in the UK has gained the plant the Royal Horticultural Society’s Award of Garden Merit.
Darlingtonia californica has mostly-upright tubular leaves with a cobra-like hood complete with fang-like appendages. The leaves exude a sweet scent to attract insects to the plant. Nectar secreting cells line the trap opening and fangs, which attract foraging insects. The translucent window-like effect in the plant’s hood confuses the insects into making futile attempts at escape which ultimately ends in exhaustion, drowning and digestion. Unlike many carnivorous plants that produce enzymes to aid in digestion, Darlingtonia appears to rely on symbiotic microbes to help break down their prey.
The flowers of the Cobra plant are also rather unusual. Each rosette of leaves generally produces a tall scape with a single flower in the spring. The flowers begin as upright buds, but become pendant when mature. Five yellow-green sepals hang loosely around five crimson petals. The petals almost completely enclose the reproductive whorls, except for windows formed by notches in adjacent petals, which allow access to the flower’s interior. 12 to 15 stamens are located at the base of a bell-shaped ovary. Darlingtonia flowers produce no nectar, and thus abundant pollen is the only likely reward for pollinators. Following pollination and subsequent fertilization, the flowers mature into upright capsules capable of producing over 2000 seeds.
II. How to Grow and Care
Sunlight
Cobra lilies will grow best in either full sun or partial shade. They will thrive when the roots are kept cooler than the rest of the plant. In full sun they tend to appear shorter and redder, while in partial shade conditions these plants grow taller and greener. Cobra lily plants do, however, need a balanced, even light distribution in order to promote vibrant colors on its sepals.
Temperature and Humidity
Though they do require cooler temperatures, humidity levels won’t necessarily impact the growth of your cobra lily. However, it’s recommended that humidity levels be kept at about 50 percent, which will help prevent the plant from drying out.
Cobra lilies will not do well in excessively warm temperatures and prefer locations with cooler temperatures at night (in the 50s or 60s).
Watering
Your watering method will be the most important factor in growing Darlingtonia. Soil aeration is vital for it. We highly recommend watering your Darlingtonia daily and allowing it to drain through completely rather than setting it in standing water as you would for Sarracenia. Daily watering mimics what Darlingtonia experience in the wild, where a constant, slow stream of cool water washes over its roots, cooling the plant and rinsing the soil of nutrients or organic chemical buildup.
On hot summer days, water your Darlingtonia in the morning and evening. If you have trouble remembering to water your plant daily, consider using a faucet timer with a drip system. If daily watering is not feasible, then use the tray method and keep your plant in small amounts of water, no more than 1/2 inch.
Darlingtonia is tolerant of relatively hard water, up to 150 ppm of dissolved minerals, so using pure water (under 50 ppm of dissolved minerals) isn’t at all necessary as long as you’re allowing the water to drain through. If you choose to set your plant in standing water, you should use pure water.
Soil
While proper irrigation is important to successfully grow cobra lily plants, the soil also has to be just right. Many gardeners opt for peat moss, perlite, and either lava rock or pumice to help create a soil mixture that allows for some cooling of the root system.
Fertilizing
The carnivorous cobra lily plants don’t require fertilization as they feed themselves by ingesting insects and other pests.
Pruning
The cobra lily doesn’t require extensive pruning, but you can cut back dead stems and leaves on an as-needed basis.
Propagation
Propagation can be done by cutting the stolons of these plants, which will produce more surviving buds when compared to seed planting. It also leads to a larger, healthier breed of cobra lily plants.
Seeds can also be used, but they will have to be kept refrigerated until the first quarter of the year (preferably February) and then planted in cold temperatures in sphagnum moss.
Here’s how to propagate cobra lily through root cuttings:
- You will need scissors sterilized with alcohol, live sphagnum moss, a seed tray, a plastic bag, and distilled water.
- Cut stolons (a stem branching horizontally from the root that runs along the soil’s surface and has buds at the ends) from the main plant. The stolons will have a mini plant growing from the top of the stem.
- Use the whole stolon as a propagation specimen, or create cuttings from 2-inch sections of the stolon, which should contain rootlets.
- Lay stolons on top of wet live sphagnum moss and keep them in indirect, bright light and covered with an unsealed bag to trap in humidity. Keep moss moist with cool, distilled water.
- Transfer to a larger pot or the garden once real leaves appear.
Potting and Repotting
Since cool temperatures are so important when growing cobra lilies, you should opt for a plant container that is light in color and has proper drainage. Plastic pots, terra-cotta clay, and glazed ceramics are all acceptable options, as long as the container you choose does not absorb heat.
To maintain proper drainage and provide more space for the roots to grow, repot cobra lily every two years, after dormancy ends but before new growth begins in the spring. Use a pot that’s at least 12-inches wide for mature plants in live sphagnum moss or a mixture of peat moss, perlite, and volcanic rock, and provide a tray underneath so the pot can stand in water to retain most soil.
Overwintering
Cobra lily plants go dormant during the winter, and if they are not a perennial in your USDA growing zone, they will need to be brought indoors. Cobra lily should be overwintered in a bright, cold room while sitting in a tray of distilled water.
