Sarracenia

Leaves that work as pitfall traps

Almost every leaf a Sarracenia makes in the growing season is a pitcher: a tube that tapers from a narrow base to an opening at the top, with a hood growing from the back of the rim ^[2]. Nectar, color and scent can lure insects to the mouth, where a slippery lip and waxy inner wall make them fall in. The tall, narrow pitchers of most species hold little or no free water. Prey that drops in cannot climb back out and dies in the tube, and the hood keeps out most rain ^[11]. The plant then breaks the prey down with its own digestive enzymes, helped by other organisms living in the pitcher ^[12].

Two departures from that design matter for growers:

• Open water traps. S. purpurea and S. rosea have squat, urn-shaped pitchers whose hood stands upright instead of covering the mouth, so the pitchers fill with rainwater and drown their prey ^{[2, 11]}.
• The lobster pot. S. psittacina lays its pitchers along the ground. The entrance is on the side, under a ball-shaped hood dotted with white windows (areoles). Insects that get in move toward the light of the windows rather than back to the dark entrance, and inward-pointing hairs steer them down the tube ^{[2, 11]}.

Some species also make phyllodia, flat leaves without a pitcher, in midsummer. Pitcher shape changes through the season and in shade, which is why Flora of North America (FNA) says species should be identified from the largest pitchers of healthy plants in full sun ^[2].

The flowers are as distinctive as the pitchers. Each is held on its own leafless stalk (scape), and the style spreads into an umbrella-like disc with five lobes ^[2]. Flowers usually open in spring, slightly before or together with the first pitchers. A visiting bumblebee enters under a sepal at one of the umbrella tips, brushing past a stigma, and leaves by pushing under a petal, a one-way route that keeps a flower from being pollinated with its own pollen ^[13].

Eleven species, more names

Both WCVP and FNA accept 11 species ^{[1, 2]}. The ICPS guide counts “15 species and subspecies” because several species are split further ^[3]. Two groups cause most of the confusion.

The S. rubra complex can be read as three species (S. rubra, S. jonesii and S. alabamensis) or as one species with five subspecies. The FNA authors take the first view but note that the five taxa have practically identical flowers ^[7]. WCVP follows the three-species view ^[1]. The IUCN Red List, the US Endangered Species Act list and CITES still use S. rubra subsp. jonesii and subsp. alabamensis ^{[5, 6, 14]}.

S. rosea, named in 1999, was previously known as S. purpurea subsp. venosa var. burkii. That is the name used in Carnivorous Plant Newsletter articles of the 1990s ^[15], and IUCN still assesses the plant as S. purpurea var. burkii ^[10]. FNA separates it from S. purpurea by its pink to nearly white petals, shorter flower stalks and thicker pitcher rims ^[9].

Hybrids add another layer. The species cross readily, the offspring are fertile, and hybrid swarms are common along the Gulf Coast. Nearly every species has also turned up in the wild as an anthocyanin-free form with no red pigment ^[2]. The ICPS guide notes there are thousands of hybrids in cultivation ^[3].

Profiled species at a glance (pitcher and petal traits from the FNA key, native range from WCVP) ^{[2, 1]}:

Where they grow

Southeastern Sarracenia habitats depend on fire, especially pine flatwoods and savannas. Without regular burns these open, sunny, acidic sites fill with shrubs and grasses, and the pitcher plants end up shaded and weak until the next fire ^[2]. The ICPS guide sorts the genus into two climate groups. Taxa confined to the Gulf Coast are warm temperate: they expect seasons but cope poorly with freezing weather and short growing seasons. Taxa from inland sites or the Atlantic coast from Virginia south are more cold temperate ^[3]. S. jonesii, for example, grows in mountain seepage bogs at 300 to 600 m ^[4].

Matching species to your winter

ICPS gives hardiness by USDA zone. The danger is early and late freezes that hit plants before they are fully dormant. Dormant potted plants can survive a few weeks frozen solid as long as they do not dry out ^[3].

Freeze damage shows up as mushy rhizome rot, most often in S. psittacina, S. minor and S. leucophylla ^[16]. The dormancy guide covers winter storage in more detail.

Care the whole genus shares

The ICPS guide calls Sarracenia among the easiest carnivorous plants for anyone with a full-sun spot outdoors and low-mineral water ^[3]. The basics:

• Water: never let them dry out. Mature plants do best in pots 16 to 20 cm (6 to 8 in) wide standing in 4 to 6 cm of water ^[3]. Use water below 100 ppm total dissolved solids; each plant can use about a liter a day in summer ^[17]. See water for carnivorous plants.
• Soil: the default is 1:1 peat and sand; outdoors, perlite can replace the sand ^[3].
• Feeding: soil fertilizer does little for mature plants and can feed the fungi behind rhizome rot ^{[3, 16]}.
• Trimming: remove only the brown parts of leaves, because the plant recycles nutrients from old green ones ^[3]. Browning pitchers in autumn are covered in Sarracenia pitchers turning brown.
• Propagation: divide well-grown clumps about every three years, just before spring growth, keeping at least three growing points per division ^[18]. Seed needs cold stratification, and it takes at least four years to go from pollination to a flowering plant ^[13].

Good first species

For growing indoors under lights all year, ICPS recommends S. psittacina and S. rosea. The tall species are hard to light from the sides indoors unless mirrors or reflective material are used ^[3]. Outdoors, choose by winter. S. purpurea subsp. purpurea is the only option in zone 5 and colder, while S. flava and the other Carolina and mountain species suit zone 6 ^[3]. An outdoor bog garden is the method ICPS describes for cold-winter areas.

Protection and trade

Three taxa have been listed as Endangered under the US Endangered Species Act: S. oreophila (1979), S. rubra subsp. jonesii (1988) and S. rubra subsp. alabamensis (1989). Several others, including S. purpurea var. montana, are under review, and S. leucophylla is a species of concern ^[6]. S. jonesii has lost 62% of its known original sites to drainage, impoundment and development, according to the NatureServe account ^[19].

All Sarracenia are listed in CITES Appendix II under annotation #4, which exempts seed, pollen, seedlings in sterile flasks and cut flowers of artificially propagated plants. S. oreophila, S. rubra subsp. alabamensis and S. rubra subsp. jonesii have been in Appendix I since 1981 and in Annex A of the EU wildlife trade rules ^{[20, 14, 21]}. ICPS condemns collecting from the wild as unethical, all the more so because nursery-grown plants are easy to find ^[22].