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THE CARE & FEEDING OF DARLINGTONIA CALIFORNICA – THE COBRA LILYÓ2004

By Karen Oudean

The Cobra Lily looks very much like its namesake. It even has what appears to be a forked tongue in front of its mouth. Unlike the snake, its favorite foods are ants, mosquitoes, flies, and wasps. More cunning than the reptile, the plant attracts its dinner with deliciously fragrant nectar secreted around its tongue and mouth. Each twisted Cobra shaped leaf is a hollow pit fall trap. Glands inside each leaf ooze fluid when stimulated by struggling bugs. Enzymes and bacteria digest victims. Lured inside the head of the Cobra, the prey wanders around consuming the musky, sticky nectar that brought it there. As the insect looks around, it sees windows everywhere. It bangs its head on the false exits and, in confusion or concussion, slides down the tube of the leaf on downward pointing hairs into digestive fluid. In about a week the insect is reduced to soluble nutrients and a nonsoluble exoskeleton. Bugs dinners are not required for the plants’ survival as long as it has high enough light levels to conduct photosynthesis. Meat is not a good substitute for insects. Harmful bacteria in the meat grow faster than the plant digests.

Darlingtonia californica, the Cobra Lily is native to cool bogs and seeps in Oregon and Northern California. It is a long-lived plant, which will send out stolons and produce a mat of plants in a few years. It does have a few requirements that must be met if it is to grow and thrive. Provide for its basic needs and you will be amply rewarded. Its spring flowers are subtle and very orchid like.

1. Temperature requirement:

A. Air Temperature can vary widely.

Summer: 50°F to 90°F

Winter: 12°F to 50°F

B. Root Zone Temperature is crucial.

1. Summer: 60°F to 68°F- best growing temperatures. In none coastal areas or hot climates, keep root zone under 75°F. The roots will collapse and the plant will die if the roots are to hot for too long a time, unless the soil is aerated by cool moving water.

2. Winter: 35°F to 50°F best dormancy temperatures for at least 4 months. According to our own experiments in Washington state the plant can tolerate from 12°F to 50°F in outdoor bogs.

3. Indoor Culture: Plants can be grown in pots in cool windowsills. If room temperatures are to high, place the pots in gravel in a terrarium with circulating water or an air bubbler to cool the root zone. If necessary, place the terrarium on the floor where it is cooler.

4. Outdoor culture: Bogs can be created outdoors using pond liners or kids wadding pools. Almost anything that holds water will work. Do not use treated wood or unsealed cement. Most carnivorous plants do not tolerate calcium, alkaline conditions or petroleum residues. If you use a pond liner, build the bog as you would a pond 12”-24” deep. Place rocks or bricks to form a retaining wall that divides the space so that ¼ will hold water and ¾ will hold wet soil. Line the area to be used for soil with weed cloth to prevent seepage of soil through the rocks or bricks into the pond area. Mix equal parts of clean sand (not from areas contaminated by salt water) and peat moss (no soil conditioners or additives). Mound the soil 4”-5” higher than the overflow level of the bog. In cool coastal areas, e.g. Pacific Northwest, watering is necessary only during July and August. If you have left a water space equal to ¼ of the surface area of your container or liner; once a week watering during dry spells will be enough. The water level can be allowed to drop to the bottom of the liner or container as long as the top of the soil is moist. Make sure your container is located where excess water can drain away during rainy seasons. The crowns of the Cobra Lilies should always be at least 1”-2” above water level. 4”-5” is best. Use distilled or rain water to fill the water area. Water will seep through the retaining wall and weed cloth to provide constant moisture in the soil mix. Water the plants in gently after planting to get rid of air pockets. Hot climates: Make your bog 2’ to 3’ feet deep. Place the bog where it will be shaded during the hottest part of the day. You will probably also need to use weed cloth and rocks to add a creek bed to your bog. Place a submersible pump in the pond and pump the water over the creek bed. Put your water tubes in the bog under the weed cloth before you add the soil mix. The water need not move very fast. It will still help cool the soil temperatures. Any size container can be placed in the ground and set up the same way.

2. Light requirement:

A. Indoor culture: Place the plant in any windowsill that gets 6-8 hours of direct light. Make sure the sun is not heating the soil above 70° during the hottest part of the day. In a terrarium use fluorescent aquarium lights. 23W Compact fluorescent plant lights in desk lamps or 32W fluorescent shop lights or grow lights work well. Place the lights 4”-6” above tallest pitcher leaves.

B. Outdoor Culture: In the Pacific Northwest and other cloudy regions Cobra Lilies need 4 or more hours of full direct sunlight, measured in June. In the rest of the U.S.A., shade the plants during the hottest part of the day. In southern states, provide filtered shade all day.

3. Water Requirement:

A. Indoor and Outdoor Culture: Use rainwater or distilled water or water put through a reverse osmosis unit. Do not use water from water softeners that use salt. Water pH should be 4 to 6.5, slightly acid. Potted plants should be placed in bowls or saucers of water that are at least 2” shorter than the pot. This will keep the plants crown from being flooded by heavy rains and well-meaning helpers. Keep the water level 3”-6” below the rim of the pot and 2” above the pot bottom. Bog plants need constant moisture. If you are going on vacation raise the water level to 1” below the pot rim and let it drop to 1” of water in the bowl. The same water levels apply to plants in terrariums. Keep the plants in pots. Place them in gravel to hide the pots. Fill terrarium with water to 3”-6” below the top of the pots. Put an empty pot in the gravel so you can see the water level clearly. Pour water into this pot to raise the water level in the terrarium without disturbing the gravel and other landscape materials.

4. Potting Instructions:

A. Repotting can be done anytime the plant is actively growing, usually from late winter thru spring. You can use live sphagnum moss or a soil mix of 1 part peat moss and 1 to 2 parts superfine perlite and/or clean builder’s sand. Do not use sand from sources contaminated by salt water. Sand from creek or riverbeds is fine if moving water and ground water both test acid pH 4 to 6.5 with an aquarium water test kit. Mix the soil mix well before you add water. Partially fill your container. Place the plant’s rhizome horizontally, at or slightly below the top of the pot. Cover the roots, and bank the rhizome, with soil to hold the plant in place. The crown should be above the soil level. Water from above to settle the soil and the plant. Tap the pot to further settle the plant and remove air pockets. Place your successfully potted plant in a water tray or bowl. Do not fertilize!

For more information:

There is an excellent TIME/LIFE videotape at most public libraries entitled “Death Trap”. Timber Press carries the book “Carnivorous Plants of the World” by Pietropaolo and Pietropaolo. Donald E. Schnell’s book “Carnivorous Plants of the United States and Canada”, first or second edition, is also very informative. “The Savage Garden” is a great new book by Peter D’Amato.