Nepenthes Edwardsiana

This species is by far one of the most sought after Nepenthes. Fortunately, it is not that difficult to grow!

A bit of backstory on the species cultivation history:

This species was largely unavailable until the late 2000s (2009 if I recall), when Andreas Wistuba announced that he would finally have the species for sale. The plant had been sold previously on a few occasions; Rob Sacilotto had sold a few seedlings, and Malesiana tropicals sold several larger rooted cuttings. Unfortunately, the waitlist for Wistuba was very long, but at the time this was the only ethical source of N. Edwardsiana available. I applied for the waitlist and four years later, I received my first N. Edwardsiana. 

Unfortunately this species has been heavily targeted by poachers. Since 2020, the main population on Mt. Tambuyukon has seen a noticeable decline. On Mt. Tambuyukon, the Edwardsiana were mainly located around a campsite called "Jeneral camp" (2000m elevation). Groups would often make the extra effort to camp here, as the entire area was surrounded by Edwardsiana's bright red pitchers in the trees. On my expedition in 2024, the camp site was completely devoid of any plants. Some group members spent a few hours searching the area, but couldn't find any plants. Above Jeneral Camp, I only counted about 30 mature edwardsiana before emerging from the canopy into the habitat of N. Villosa. Other populations don't appear to be doing so well either. On Mt. Kinabalu, Edwardsiana grows on the Marai Parai plateau and along a few adjacent ridges. While I have never been there myself, guides have told me that roughly a dozen mature plants grow there. 

One of the few remaining N. Edwardsiana we found on Mt. Tambuyukon at 2100m. Unfortunately this plant was poached about a year after my visit.

As a contrast, the populations of N. Villosa and N. Macrophylla still number in the hundreds. I suspect these species are less poached because they are generally harder to acclimate from cuttings, and N. Edwardsiana is arguably the most desirable of the sabah species. 

In more recent years the species has become more widely available. As more N. Edwardsiana in cultivation reach flowering size, hopefully this trend will continue. For now this species is likely the most threatened with extinction in Sabah. 

Cultivation Requirements

Fortunately, N. Edwardsiana is the easiest to grow amongst the toothy species. From my experience, the species is quite fragile when young but becomes more resilient as the plant gets older. Every batch of seedlings I've raised has had some level of die-off within the first year after germinating. I've never been able to determine why this happens with N. Edwardsiana. At first my thought was crown-rot, but I observed the same die-off (~10-25% of seedlings) in tissue culture, so fungus does not appear to be the culprit. Don't be alarmed if this happens to you as well; other growers have also made the same observations. 

     

Fertilizer

Sept 2024 - June 2026 growth of my largest N. Edwardsiana with monthly nutricote pellet feeding. This plant was started en-vitro but deflasked in 2021 due to contamination. The largest pitchers now measure 13" tall. 

N. Edwardsiana doesn't seem to tolerate foliar fertilizer. Even at low doses, maxsea spray caused leaf burns, and the plants seemed to get upset and slow in growth. What has worked very well for me is feeding the pitchers with nutricote pellets, specifically 18-6-8 180 day release pellets. Once the pitchers are about 3" in height, start by feeding the plant small pellets once every two months. If the pitchers don't burn, try to increase the size of the pellets and feeding every to every one month. Fortunately, Edwardsiana pitchers are very woody so they can tolerate a higher fertilizer concentration than other species. The early application of nutricote will cause the leaves to double in length, with substantial increases in pitcher size! 

 

Light

A big mistake I often see with younger seedlings is that they are subjected to full light levels, causing the entire plant to turn red. While this isn't necessarily a bad thing, it does appear to slow down growth in my experience. In situ, Edwardsiana starts out in the shade, only reaching full sunlight when the vine pierces the canopy. My plants receive about 10-15 DLI (mol m⁻² d⁻¹), depending on the time of year. 

 

Temperatures

As a highland Nepenthes, N. Edwardsiana needs a nighttime temperature drop, but temperatures can be slightly higher than other more species like N. Villosa. This is largely because N. Edwardsiana grows at a lower elevation (1800-2000m) than N. Villosa, where temperatures are slightly warmer. To note, when I was on Mt. Tambuyukon, we measured the low temperature at General Camp to be 62F. This would likely be too warm for N. Villosa, which grows above General Camp's elevation (approx 2100-2500m). In my setup, nighttime temperatures are usually 58F, with daytime temperatures below 85F. I keep most of my N. Edwardsiana as hanging plants in the greenhouse rafters, where temperatures are on average about 5 degrees warmer than the greenhouse benches. The plants do not seem to mind temperatures in the mid 80s during the summer, but my attempts at placing more sensitive species like N. Villosa and N. Diabolica in the greenhouse rafters obviously didn't work. 

 

Soil

N. Edwardsiana doesn't appear to have a specific soil preference; I've seen a wide range of soil mixes work for various growers. My preference is 40% perlite, 40% coco chips, 10% akadama, 10% coco coir. Like most epiphytic Nepenthes it's important to allow the soil to breathe and not be too waterlogged. All of my Edwardsiana are setup on a four day drip system to ensure I don't overwater them by accident (or forget to water them). 

 

Why is the species so expensive? 

A common question I'm asked is why N. Edwardsiana is still so expensive despite being in cultivation for more than two decades. From a production point of view, this species does not clone well in tissue culture. For some reason, N. Edwardsiana does not respond to the hormones most commonly used in plant tissue culture. There are some synthetic hormones I've trialed on N. Edwardsiana that do allow it to clone, but these hormones produce a high number of undesirable mutations, so I do not use them. As a result, the worldwide production of this species remains low, while demand remains very high. Many new growers to the hobby desire this species long before they are capable of growing one (I was one of them!); as a result many of these younger plants die before they are able to reach maturity. 

In contrast, N. Edwardsiana from Mt. Kinabalu does respond to hormones in tissue culture. I suspect this is because most N. Edwardsiana from Mt. Kinabalu have some introgression with N. Villosa, which is quite easy to clone en-vitro. The natural hybrid N. X Harryana is often seen as a result of "N. Edwardsiana" originating from seeds collected from Mt. Kinabalu. Unlike on Mt. Tambuyukon, both species here grow sympatrically. Nonetheless, N. Harryana is still a bit finicky in tissue culture. I'm currently working on producing more of this hybrid.