Has anyone here ever added serpentinite to their Darlingtonia pots? Did it have an effect on the plant? It seems that since they are frequently found in serpentine soils in the wild, and presumably are specialized at living in such toxic areas, it might confer some sort of advantage for them in cultivation to be exposed to the minerals.
I've had my plant for a few months now, and I've surprised myself by not only keeping it alive, but getting it to thrive (I'm new to carnivorous plants). I grow it in full sunlight and have a small, solar-powered water pump that constantly flushes water over the roots. Didn't do much to keep them cool in the height of summer though, I still measured the root temperature at over 95°F some days. The plant is still happy and keeps putting out new pitchers though.
Anyway, I live right by an ultramafic rock formation, so I went and collected a few serpentinite stones to place in the pot with my plant. I'm actually hoping that as the water washes over the rocks, it will kill some of the nasty, stringy algae that grows where the water runs. I'm eager to see what (if any) effect the addition of the serpentinite will have on the plant itself... I guess I'll have to wait till next spring.
Here's a photo I just took of the plant with the new stones (the sun has already set, which is why there's no water flowing):
Several years ago I had the same question. So I collected a bucket of serpentine soil from the roadside below the covered bridge site near the Smith River. I then transplanted several of my mature Darlingtonia into 12-inch pots with a mix of 3/4 of this serpentine gravely soil and 1/4 sphagnum peat. They have been growing just fine for the last 3 years. Although far from a controlled science experiment, I don't notice any particular differences between these plants and those growing in other non-serpentine mixes. A top dressing of live sphagnum seems to assist in Darlingtonia plant happiness.
I suspect that the species has evolved to tolerate the presence of Serpentine, but I have doubts that it has any benefit. Most CP enthusiasts grow fine plants in plain ol' sand-and-peat mixtures, top dressed with live Sphagnum. That is what I do and I have had excellent results. Like you, I use a wee little pond pump to circulate water through the root zone, constantly. I do not make any effort to cool the media on hot days. Here in the PNW the summer nights are always below 60F, often cooler, which Darlingtonia need to thrive in the long run. I believe it is the day to night differential that makes or breaks a Darlingtonia culture.
Thanks for the info, guys. I guess the main benefit of the serpentine soil in the wild is that it suppresses the growth of other plants, letting the slow-growing Darlingtonia reach its full potential.
Is the benefit from the sphagnum that it helps keep the roots cool? I've tried to grow small portions of it, but I find that it just can't take the intense sunlight and desiccating humidity (I'm sure the daytime heat doesn't help either). The green moss I have in there now is some I just harvested from some potted plants and put in there, and it seems to be growing well, but it constantly produces sporophytes. I just harvested another type of moss I found growing in a sunny meadow, so I'll see if that does a bit better.
Sphagnum can withstand full sun, but only in a humid environment. Blazing sun + low humidity = fried Sphagnum. Any chance you can raise the humidity? Darlingtonia will grow reasonably well in dappled shade, which might give the Sphagnum a chance to get established also.
Nope, not much I can do about the humidity since I am growing the plant outside; even in the shade it's quite low. In the summer, the daytime humidity is typically 25-35% (sometimes higher, sometimes lower), but at night when it cools off and the fog rolls in the humidity normally goes up to 85-100%. I guess the nighttime increase isn't enough though. :\
I wanted to chime in on this conversation. I agree with most of what folks have been saying here about Darlingtonia in culture. Based on some experiences I've had in the last 3 years I want to submit another possibility about Serpentine.
Serpentine creates a fairly toxic environment for many common plants. These areas tend to be low in calcium and high in chromium and nickel. When you go into an area with Serpentine bedrock and the associated clay, you see very different and unique plant communities. Many plants normally common for the region won't grow there, or are stunted. The common theory usually proposed is that Darlingtonia can thrive here because the Serpentine keeps competition low, and that since they are carnivorous, they grow well in the low nutrient wetlands. When they are grown outside of this environment, however, they tend to die unless root temperatures are kept low, or grown in live sphagnum moss. However, I've been to several natural stands of Darlingtonia in Southern Oregon where the plants are in fully exposed sunny springs, and nothing about July and August are cool in that area. It cools down at night, but it does here at our nursery also, yet we still loose plants unless they have constant cool water, or are grown in live Sphagnum moss, or combined with light shade to keep soil temperatures low. Even then I've watched plants die for no apparent reason.
What if the problem here is a natural pathogen that is kept at bay due to the toxicity of the soil such as a fungus or bacteria? This would be consistent with other observations that Darlingtonia don't benefit directly from these minerals, but the minerals might help create a safe growing environment by keeping certain soil pests in check. This would help explain the live Sphagnum success since live Sphagnum keeps the media very acid which also might keep a pathogen at bay. Sulfur based fungicides work in a manner similar to this.
I've wanted to test this idea, but getting crushed Serpentine gravel isn't easy since it can contain small amounts of Asbestos. It's illegal in Oregon, and I think in California too, to use crushed rock containing Serpentine on roads for this reason.
I'd love to hear if others have had experience growing plants with high amounts of Serpentine in the media, and if any research has been done on plant diseases of Darlingtonia. If we knew exactly what is happening when a plant dies, what type of pathogen is killing it, or if it's just conditions, it might help to develop a more practical means of growing this amazing plant.
From Reading Books Similar to-The-Above You'll-Learn That SERPENTINE is Basically Magnesium-silicate or TALCUM-Powder IN-R-Different-Guise so-to-Speak ... Rich-IN: Nickel / Chromium as-Well-as Cobalt so-to-Speak.
Most CPs Live-In R-HALF-Way House Soil-Type-of Arrangement Where The-Nutrients R Bound-to-The Organics of The Soil-Profile though In-'Theory' It's Quite Possible to Have-it The-Other-Way Around so-to-Speak ... Something THART-Is Easily Demonstrated With Common Table-Salt That Usually Raises the Volume of R Substrate On-R ~ 1-Kilo to 1-Litre Basis ... an Increase THART-Is Little-Altered by Elution so-to-Speak (Like Iron-Filings to-R-Magnet - Easy to Stick-ON 'Harder' to Get-OFF)!!! >(*~*)< / >(*U^)<
But If-You Smart-enough to Get THIS-Far Then You've probably Already-'Made' The connection with so-Called CP-TANNINS:
Jeff - Do you find that all life stages of plants can die suddenly? Or is it mainly large, mature plants that perhaps have reached the end of their lifespan anyway? I went to go look at a population of Darlingtonia last month, and found that there were always some dead plants mixed in with perfectly healthy live ones. I'm not sure if this was because of drought, or a parasite, or some other specific problem, but it was apparent that the individual plants weren't invincible (nor vital to the population, given how they reproduce vegetatively). Maybe such deaths are just unavoidable whether the plants are in the wild or in cultivation?