Growing Guide: Nepenthes tenuis!

Nepenthes tenuis

Nepenthes tenuis is one of the delicate species of toilet bowl Nepenthes that I briefly mentioned in Cultivating Carnivorous Plants, but did not have enough space to give a flushed out description of its growing conditions. To date, it's been a somewhat rare and expensive species in cultivation, which is odd considering that many who grow it consider it somewhat of a weed given its rapid growth.

Nepenthes tenuis

I was lucky to obtain a cutting earlier this year and have found that it is a remarkably easy species in standard highland conditions. To date, the plant has rooted and put out something like five new leaves and five new pitchers all within a three month (or so) time span. That's remarkably fast for a Nepenthes, especially one in highland/intermediate conditions.

Nepenthes tenuis

Native to West Sumatra, N. tenuis grows at 1,000 - 1,200 m above sea level in a mossy/sub-montane forest along a sandstone ridge. In cultivation, I've found that it likes high humidity, cool temperatures, and an airy substrate. At present, my preferred Nepenthes media is a mixture of coir (coconut fiber/chips), perlite, New Zealand long-fiber sphagnum, orchid bark, and charcoal. This mixture has a great, airy structure and does not easily become compacted and waterlogged like a typical mixture of long-fiber sphagnum and perlite.

Nepenthes tenuis

What surprised me most about N. tenuis was the diminutive size of the pitchers. As you can see above, the pitchers are tiny! At present, they are the second smallest of the genus after Nepenthes argentii. The largest I've seen were at an NECPS Show, where the pitchers were about as large as a thumb. I mean, they're incredibly tiny! 

Nepenthes tenuis

As you can see, my plant is producing upper pitchers. (The cutting must have been from an upper part of the vine). My understanding is that this species transitions to upper pitchers almost immediately upon starting to vine, unlike some other, slower transitioning species. As a consequence, the tubby, round lower pitchers are somewhat rare to see.

Nepenthes tenuis

I also understand that there are a couple different colorations of N. tenuis in cultivation. One is rather plain and has yellowish upper pitchers, making it somewhat easy to see how, before its rediscovery in the wild, some commentators lumped this species in with N. dubia. Most specimens, however, look closer to mine, although a few have more brilliant red colors throughout.