Cultivating Carnivorous Plants (2015)
Darlingtonia californica in cultivation.
The California Cobra Lily, Darlingtonia californica, is among the most fearsome of the pitcher plants.
Reminiscent of a snake’s head, Darlingtonia pitchers, forked tongue extended, twist outwards, posing like a
cobra ready to strike. Yet, for all their fearsomeness, the pitchers do not produce poisons, not even digestive
enzymes. In fact, Darlingtonia depends largely upon bacterial action to digest its insect prey.
Darlingtonia californica in cultivation.
As with other monotypic genera, only one species of Darlingtonia exists, californica. There are, however,
three forms of the species. The first and most common form is the typical form. This form is known as
Darlingtonia californica forma californica, although most growers do not add on the forma designation. It is characterized by having a red “tongue” in bright light and occasionally some red on the hood of the pitcher
The second form was once known by the cultivator name “Othello,” but it is now known as forma
viridiflora. A lack of anthocyanin, or red pigment, characterizes forma viridiflora. The lack of anthocyanin causes
forma viridiflora to be entirely green. In low light conditions, distinguishing forma virdiflora from the typical form
may be possible, but their flowers set them apart. Forma viridiflora’s flowers entirely lack red pigmentation,
whereas the typical form’s feature red sepals.
The third form is rare, entirely red, and, like many of its Sarracenia cousins, known as forma atropurpurea.
CULTIVATING CARNIVOROUS PLANTS
Although some typical plants may initially show entirely red coloration, these revert back to the typical
coloration pattern upon reaching adulthood. Entirely red adult pitchers are the characteristic that
distinguishes forma atropurpurea.
There is some indication that other forma exist. Recent expeditions into the field discovered pitchers with
red a ring of red pigmentation around the “windows” on the pitcher hood. Other reported mutations include
color variations and pitcher variations. More fieldwork is necessary before determining whether these forma
Darlingtonia californica off the Rocky Creek Trail in Oregon.10
Darlingtonia is unique among carnivorous plants because it grows in two distinct habitats - coastal and
montane. Coastal plants experience warm day temperatures, around 70° - 75° F (21° - 24° C), and high
humidity from the frequent coastal breezes. Montane plants, in contrast, can experience very hot daytime
temperatures, up to 110° F (43° C), and much lower humidity.
Coastal plants often inhabit
what is thought of as a “typical”
sphagnum bogs. In contrast,
montane plants often inhabit
fens, i.e. marshy, alkaline habitats
atop serpentine soils. Snowmelt
and cold springs feed these fens,
so the roots of the plants remain
cool when temperatures soar.
(Coastal plants, however, always
have cool roots because the air
temperature does not rise very
far, and the roots of plants are
often shaded by plant growth).
habitats experience cool night
time temperatures during the
height of summer, often down to
Darlingtonia in the wild at Darlingtonia State Natural Site
60° F (16° C).
(Formerly known as Darlingtonia Wayside).
Of course, there is habitat variation, and some features of coastal habitats can occasionally be found in
montane habitats, and vice versa, but, for the most part, these two habitats are entirely separate. Recent
research has indicated that there might be three different habitats. To date, no cultivation studies have been
conducted regarding this claim, and it is unknown whether there are actually three different habitats that
Darlingtonia can inhabit. Currently, cultivation studies only support division into coastal and montane habitats.
The separation between coastal and montane habitats remains in cultivation. Darlingtonia originating
from coastal regions require conditions similar to those they experience in nature, i.e. constantly cool roots
and cooler temperatures. Darlingtonia originating from montane regions, in contrast, are better able to tolerate
a wider-range of conditions, including hot daytime temperatures, as long as night temperatures are cool.
For both coastal and montane Darlingtonia, the key to long-term cultivation is cool nighttime
temperatures, and, with coastal Darlingtonia, cool daytime temperatures as well. Most growers find that
montane-region Darlingtonia are easier to grow long-term; replicating coastal California’s and Oregon’s climate
year-round is difficult. If established, montane plants can experience warm to hot roots during the day
without issue, as long as the plant experiences nighttime temperature drops to near 60° F (16° C).
The easiest way to keep roots cool is to use an airy media mix, such as one part long fiber sphagnum and
one part perlite. Using large, light colored, especially white, pots helps keep roots cool. Flushing the pot with
chilled water at least once per day is also advisable.
CULTIVATING CARNIVOROUS PLANTS
Typical Darlingtonia flower.11
My standard growing guide for Darlingtonia follows:
Media: Darlingtonia do well in a mix of one part sphagnum to one part perlite or orchid bark. It
is not known whether adding an ultramafic rock, such as serpentinite, would increase growth.
Moisture: Watering via the tray method, and always keeping some water in the tray, is probably
the easiest way to meet the moisture and humidity requirements of Darlingtonia during the
growing season. It is also advisable to flush the pot with chilled water at least once a day,
although many plants will be subjected to a constant flow of chilled water in the wild. During
dormancy, soil should remain moist, but not soaking in order to prevent rot.
Humidity: Coastal Darlingtonia need higher humidity than montane Darlingtonia. In general, the
species has the same humidity requirements as its cousins, the Sarracenia.
Pot Size: Pots should be much larger than the plant in diameter, but do not need to be very
deep. The plant will spread via lateral rhizome growth in good conditions, meaning the pots
must be large to accommodate the growths. The roots, however, do not ordinarily grow very
deep compared to other plants.
Feeding: Feeding Darlingtonia is difficult. Unlike Sarracenia, Darlingtonia does not appear to
benefit from the placement of a few osmocote-type pellets near their roots. Nor does
Darlingtonia benefit from foliar fertilizer. It may, however, benefit from insects added to the
Temperature: Montane Darlingtonia can tolerate a wide range of above-freezing temperatures
during the growing season, but care should be taken to try to restrict their upper limit to 90° F
(32° C) with temperature drops to 60° F (15° C) at night. Coastal Darlingtonia should experience
cooler temperatures, never exceeding 75° F (24° C).
Dormancy: Dormancy is required for Darlingtonia. In cold climates, plants can be left outdoors,
but, in warmer climates, plants should be chilled in the same manner as Sarracenia.
Propagation: Darlingtonia can be propagated via the following methods:
Division: The easiest way to propagate Darlingtonia is to divide the smaller, lateral
offshoots from the larger, more mature plants. It is better to wait for the offshoots to
form their own root systems and become somewhat established before dividing them
because, otherwise, they could easily die from lack of water.
Seed: Darlingtonia may also be propagated via seed. Fresh seed should be sown on a
suitable media and cold stratified for six weeks. The easiest way to do this is to cover
the pot with plastic wrap and place in the refrigerator for six weeks. Then, the pot
should be removed and placed in a location with temperatures and light similar to adult