August Showers (and July Heatwaves) Bring September Sarracenia Flowers

Under normal conditions, Sarracenia pitcher plants bloom once: in spring. Many carnivorous and protocarnivorous plants can bear flowers at different times through the year, and frail triggerplants are so profligate that the trick is to get them to stop blooming. Sarracenia, though, are very consistent. They bloom before producing traps, presumably because Sarracenia pollinators in spring tend to be top prey insects the rest of the year, and the seed pods mature throughout summer before cracking open and scattering seed at the beginning of winter. Once those blooms drop their petals in late April or early May, that’s it, right?

Well, not always. Every once in a while, you’ll see an anomaly. Toward the end of September, as temperatures cool and the pitcher plants perk up for autumn, you might find a bloom or two. The blooms may be full-sized, but the flower scapes from which they dangle are abnormally short, sometimes just a couple of centimeters tall. Any fragrance on the blooms tends to be diminished as well, from the Kool-Aid scent of S. leucophylla to the “last day of an anime convention” stench of S. flava, and the distinctive cap at the bottom of the bloom also shows anomalous development. (The image below shows the bloom cap on S. leucophylla “Compacta”, with unusual deformities and an incomplete cap, with exposed anthers.)

The hypothesis here is that these September blooms are a response to the abnormally hot and dry summer in North Texas, as well as the subsequent low humidity after our torrential rains in August and early September. These seem to be most common on S. flava and associated hybrids, with a few seen on S. leucophylla and S. minor and their hybrids. With the latter, the flower scapes range from short to normal height, with S. minor being the most likely to produce full-length flower scapes. So far, I have yet to see any on S. rubra, S. oreophylla, or S. purpurea or their variations or hybrids.

An interesting correlation, which requires further research, is that the likelihood of September blooms depends upon when the plant blooms in spring. By far, the most common September blooms come from S. flava, which is famed for blooming as much as a month before other Sarracenia species. In North Texas, S. leucophylla is particularly sensitive to late freezes in spring, sometimes only starting to bloom three weeks after all others have finished for the season.

The hypothesis: this trait expresses itself after especially stressful summers, where the plant survives but the seed pods may be damaged from extended heat. The blooms themselves appear to be viable based on the enthusiastic efforts by local bees and wasps to gather nectar and pollen, but gathering and attempting to germinate any seeds from these blooms is the only way to confirm whether the seeds are viable. I am already gathering seed from early-maturing spring seed pods and getting ready to gather ones opening later in the season, and comparing germination and growth of seedlings from each group will be necessary to determine if the September blooms are a useful strategy for a seed do-over after an especially brutal summer. We’ll all find out more for certain next spring.

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