A Tour of Chester Zoo's Nepenthes Collection
Published 13 June 2018, updated
Chester Zoo is home to one of the largest collections of carnivorous plants in the UK. Their National Plant Collection of Nepenthes holds over 2500 individual plants from 130 species and countless hybrids, many of which are facing imminent extinction in the wild.
Last week I visited Chester Zoo for a behind-the-scenes tour of their three glasshouses, which are not open to the public, with Lead Horticulturist Paul Leach. He’s been growing Nepenthes at the zoo for over 20 years and has been responsible for the National Collection since Chester first acquired it from Derek Clavell-Bate in 2011.
The decision to buy the collection - which already contained a number of highly endangered species - can be traced right back to the zoo’s mission statement: ‘preventing extinction’. The collection not only highlights the threats posed by habitat destruction and poaching, but has also enabled the zoo to make invaluable contributions to vital conservation projects. Paul explained: “We have already sent cuttings of N. kampotiana back to Thailand to help with a re-population project, and there are other projects in the pipeline for other species.”
Today the collection is spread across three glasshouses, each representing a different environment: lowland, intermediate, and highland. My tour began in the highland glasshouse, the largest of the three.
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The highland Nepenthes glasshouse.
Nepenthes x Tiveyi (N. veitchii 'striped' x N. maxima 'superba').
Nepenthes flava.
Nepenthes spectabilis (Sinabung).
Nepenthes truncata 'black'.
Nepenthes lowii x campanulata.
Nepenthes 'Lady Pauline' (N. talangensis x maxima).
Nepenthes burbidgeae - I really love the red to cream fading of the peristome on this species.
A cream-coloured pitcher on Nepenthes burbidgeae.
Nepenthes ventricosa 'porcelain'.
Nepenthes maxima 'dark' x trusmadiensis.
Dozens of the of plants were in flower or setting seed.
Nepenthes spathulata x spectabilis.
Nepenthes ventricosa x inermis was a prolific producer of pitchers, as you can see from this bushy plant.
Nepenthes ventricosa x inermis pitcher.
Nepenthes veitchii x lowii, a fantastic hybrid.
Nepenthes fusca.
Nepenthes 'Emmarene' (N. khasiana x ventricosa).
Nepenthes copelandii.
Nepenthes maxima upper pitcher.
Nepenthes 'Judith Finn' (N. veitchii x spathulata).
One of my favourite species, Nepenthes veitchii. This particular specimen had a bright red peristome and was particularly hairy.
The whole plant was covered in thick bristly hair.
Close by, a Nepenthes veitchii 'golden peristome'.
Close up of the N. veitchii 'golden peristome'.
Nepenthes alata.
Another Nepenthes maxima 'dark' x trusmadiensis, this one with a wider, more lowii-esque mouth.
Nepenthes burbidgeae x fallax (N. stenophylla?).
The stunning Nepenthes lowii - I can't wait until my plant produces uppers like this.
Close up of the lid bristles on Nepenthes lowii.
Nepenthes ventricosa x ovata.
A huge and lovely N. carunculata var robusta (aka N. bongso).
Nepenthes bongso with my hand for scale.
Lovely little pitchers on this plant - I couldn't see label, but it looked like it might be N. pitopangii.
Nepenthes glandulifera.
Nepenthes rigidifolia, one of several species held by Chester Zoo which is possibly extinct in the wild.
Nepenthes singalana.
Nepenthes dietas.
Nepenthes ventricosa x ephippiata.
An unknown hybrid involving N. spathulata.
Nepenthes mikeii.
Nepenthes petiolata.
A really nice hybrid I had never seen before: Nepenthes aristolochoides x hamata. I think this cross was by Simon Lumb. Great shape.
Glossy black toothy peristome on Nepenthes aristolochoides x hamata.
Nepenthes adrianii lower pitcher.
Nepenthes adrianii upper pitcher.
The distinctive Nepenthes x briggsiana (N. lowii x ventricosa).
Nepenthes tobaica (Dolok Sanggul).
Nepenthes tobaica again, with my hand for scale.
Nepenthes glabrata - I really like this species.
Nepenthes tenuis.
Seeing all these smaller species reminded me of a conversation I had with Andy Smith a few weeks ago - we both felt that many miniature species like N. tenuis and N. glabrata are underused in crosses. I'd love to see more hybrids with these smaller Nepenthes.
Nepenthes robcantleyi.
The distinctive peltate leaves of Nepenthes peltata.
This N. peltata didn't currently have any pitchers, but here you can see the red underside of the leaves and hairy tendril.
Nepenthes spathulata.
The fearsome Nepenthes hamata - this was labeled as Wistuba clone 1.
Nepenthes ephippiata lower pitcher. I'd love to grow this species one day.
Close up of Nepenthes ephippiata lid bristles and lovely orange peristome.
Another Nepenthes burbidgeae, this one a bit larger.
Nepenthes leonardoi.
The nursery for smaller plants. There were some really nice seedlings here including N. attenboroughii, N. leonardoi, N. lamii, and N. pitopangii.
Paul looking over the plants in the highland nursery.
The highland glasshouse is controlled by an automated system which manages the heaters, roof vents, and lights. The environment is kept at around 24°C during the day and 14°C at night, in contrast to the lowland house which is kept at a constant 30°C. Watering with rainwater is done by hand every day, but supported in the highland and intermediate glasshouses with an overhead misting system.
One of the things which struck me while exploring the glasshouse was the sheer size of many of the plants. Paul explained that he refrains from pruning scrambling vines and instead allows the plants to grow naturally, staking larger specimens with canes to support them. As well as making great use of the glasshouse’s height, it also means that the contrasting morphology of many species’ lower and upper pitchers was displayed to full effect. Cuttings are typically only taken as a way to build up numbers of rarer species as a safeguard.
Most of Chester’s Nepenthes are grown in a peat-free mixture, but Paul is always open to trying new mixtures. “I normally use a mix of New Zealand sterilised moss with perhaps moss peat or bark, perlite, or silver sand maybe added at times. I always need vast quantities for the collection!”
When it comes to fertilization, Paul is a fan of experimentation. He’s tried numerous different approaches including the famous coffee method, much to the confusion of the zoo’s catering team. Today, however, he typically relies on Osmocote: he drops one or two pellets into a single pitcher on each plant per month. The plants certainly seem to appreciate being fed like this, with most of the larger plants holding dozens of colourful pitchers at once.
Next, we entered the intermediate and lowland glasshouses.
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Stepping into the considerably warmer intermediate/lowland areas, the first plant I spotted was this Nepenthes bicalcarata, with distinctive fangs and thickly coiled tendril. Along with N. platychila and N. inermis, this is one of Paul's favourite species.
This N. bicalcarata upper pitcher was particularly stunning, and as you can see was dripping with sweet nectar.
An older lower pitcher on Nepenthes bicalcarata.
The huge N. bicalcarata had one of the thickest, woodiest stems I think I've ever seen.
At first I thought this was a huge N. 'Bloody Mary', the Borneo Exotics cross between N. ampullaria and N. ventricosa, but it was actually N. ampullaria x sibuyanensis, which explains the size!
I couldn't see a label on this species, but there was something I liked about the rusty red peristome.
A particularly lovely Nepenthes boschiana from Ganung Sakumpang.
Huge elongated pitchers on Nepenthes boschiana.
Nepenthes boschiana upper pitcher.
Nepenthes bokorensis.
A young Nepenthes campanulata.
As in the highland house, dozens of plants were flowering at once. Given the sheer size of the collection, only very specific plants are prioritized for pollination and seed collection.
Close-up of Nepenthes inflorescence.
Nepenthes x oisoensis - I think this a Japanese cross, it might be N. northiana x maxima but I'm not sure.
Nepenthes thai.
An upper pitcher on a different form of Nepenthes boschiana.
Nepenthes platychila upper pitcher displaying wide flared peristome. A beautiful plant!
I spotted a nice little orange Nepenthes ampullaria down near the floor.
Probably the biggest plant I saw during my visit - Nepenthes truncata x merrilliana.
Selfie with Paul and Chester's Nepenthes truncata x merrilliana.
Heading into the true lowland house, the first plant I saw was Nepenthes rafflesiana.
Nepenthes mirabilis var globosa - I've always loved the shape of this species.
Nepenthes ampullaria 'Harlequin'.
Nepenthes kampotiana. Chester Zoo has previously sent cuttings of this species back to Thailand to help with a re-population project.
Nepenthes ampullaria 'Cantleys Red'.
This was labelled as Nepenthes × coccinea, a very old hybrid which was popular with the Victorians - (N. rafflesiana × N. ampullaria) × N. mirabilis. I haven't seen a green form before.
The lovely white rim of trichomes on Nepenthes albomarginata, a red form from Gunung Jerai in Peninsular Malaysia.
A green form of Nepenthes albomarginata.
Given the number of plants which were at varying stages of flowering, I asked Paul whether he and his team ever propagate from seed. Given the size of the collection and the length of time it takes to raise mature plants from seed, typically only very specific plants are prioritized for pollination and seed collection. “We do hold seed and/or pollen at times, and we are always open to exchanges as long as everything is legally obtained,” he elaborated.
While the Nepenthes glasshouses are not currently accessible to the public, the team have experimented with integrating certain specimens into public areas. This includes a particularly fantastic display overhanging the cliff face in the Monsoon Forest area. Public displays such as these usually involve hybrids, partly to avoid risking individual species, but also because hybrids are more likely to tolerate the occasionally suboptimal conditions found in the animal houses.
“The response to these plants has been amazement and surprise; people do not often see these plants anywhere else,” Paul observed. I also spoke to Phil Esseen, Curator of Botany and Horticulture, who explained that striking and unusual plants like Nepenthes are being tested as a way to combat ‘plant blindness’ - the tendency for visitors to overlook plants completely. While perhaps inevitable to a degree given the setting (many visitors to the zoo arrive with the specific intention of learning about animals) staff are keen to raise awareness of threats to biodiversity and the importance of conservation for all lifeforms, including plants.
During my day at the zoo, I was also treated to a tour of the new outdoor Sarracenia display and orchid house and with Phil Esseen, and of the impressive cacti collection with Lead Horticulturist Jo Adderley. A select handful of my photos are presented below.
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The public Sarracenia bed.
Sarracenia jonesii.
Sarracenia leucophylla.
The cacti collection at Chester Zoo.
I'm woefully ignorant about cacti species, but many of the specimens in Chester's collection were beautiful.
Cacti in bloom.
Cacti in bloom.
Among the many things Jo taught me about cacti: while morphology can often vary wildly between species of the same genus, their flowers are often very similar and can sometimes be helpful for identification.
Adenium obesum in bloom, from South Africa.
The orchid display.
Orchids flowering.
My favourite of the orchid flowers I saw.
Before leaving the zoo I asked Paul if he’d share a few tips for Nepenthes growers. He emphasised that there was no one-size-fits-all solution; the huge number of variables means you shouldn’t be afraid to experiment when looking for an approach which suits you. “The only tip I would offer to all growers is to regularly check your plants, daily if possible - spot problems early and they are easier to deal with.” My Nepenthes grow guide is available here.
I’d like to say a huge thanks to Paul, Phil, Richard and Jo for making me feel so welcome and for showing me round the zoo’s incredible collections. If you’d like to learn more about Chester Zoo’s important conservation work, you can visit their website. If you’re a member of the Carnivorous Plant Society, be sure to keep an eye out for Chester Zoo’s next Open Day.
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I've been growing carnivorous plants for over 2 decades, having been fascinated by these plants since I got my first Venus flytrap at age 10. I now have a large greenhouse to house my collection and am an avid breeder of Nepenthes pitcher plants.
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