The cobra lily can be a difficult plant to grow well, as its roots must be kept cool. This is a challenge during the hot summers of the mid-Atlantic region. While care for cobra lilies is similar to that of Venus flytraps and North American pitcher plants, modifications are necessary to keep the roots cool.
Where to Grow: Outdoors.
Light: Cobra lilies grow anywhere from full sun to part shade (outdoors). Although they appreciate full sun, this may overheat the roots during the summer. Under hot conditions, consider shading the pot/plant.
Water: Use distilled/rainwater/reverse osmosis water ONLY. That means NO TAP WATER. Place the plant in a tray of water, but also water overhead with cool water. In the summer, ice cubes made from distilled/rainwater/RO water can be placed on the soil. On very hot days, flushing the pot with refrigerated water may help.
Soil: The soil mix should allow for aeration, which means that rocky ingredients like perlite, lava rock, and pumice can help. A good mix is equal parts sphagnum peat moss, coarse (#12 silica sand or similar) sand, and perlite. If sand cannot be found, perlite can also be substituted for a mix of two parts perlite and one part sphagnum peat moss. Another recipe is four parts long fibered sphagnum moss and one part perlite or pumice. Make sure all soil ingredients are free of fertilizers and added minerals.
Containers: Plastic pots are best. Avoid unglazed terra cotta plants, because they can wick water away from the plants and also leach minerals into the soil. Avoid dark colors for the pot, which absorb heat.
Feeding: The plants will likely catch all the insects they need, but can also be fed small insects from time to time.
Fertilizing: As a general rule, avoid using any fertilizer on cobra lilies.
Humidity: Usually not a concern.
Dormancy (Winter Care): Cobra lilies go into dormancy in the winter months, generally between October and March. During this time, they may stop growing and look dead. Dormancy is triggered by shorter daylight hours and colder temperatures. In the mid-Atlantic region, plants can overwinter outdoors provided they are either mulched heavily with pine needles/bark (bury the pots under several inches of mulch) or placed into a cold frame. Alternatively, some growers have had success with placing the plants in an unheated garage as long as the plants can still receive some light. During dormancy, the soil should be kept damp, not very wet. The plants can survive frosts and even some brief freezes.