Philodendron spiritus-sancti Aroid Culture & Care Sheet

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Species Name: Philodendron spiritus-sancti (PSS)

Subgenus: Philodendron | Section: Calostigma
Care Group: See Aroid Care & Culture Tips for Indoor Growers

This Philodendron spiritus-sancti care sheet is long, so I’ve linked the sections to make it easier to skim. Click on the section you want to know more about or continue reading through.

 

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Habitat & Ecology of Philodendron spiritus-sancti

Elevation: 650m
Distribution: Domingos Martins, Espírito Santo, Brazil – (see Kew.org)
Closely-Related Allied Species: Philodendron quinquenervium (guaraense), Philodendron cordatum, Philodendron minarum (see Aroideana, Vol. 24, pg 18-23 – available from the IAS)
Other Philodendron species from Espírito Santo, Brazil: Philodendron bernardopazii (Superbum) [photo], Philodendron ricardoi [photo], Philodendron rhodospermum, Philodendron hatschbachii, Philodendron ruthianum

Photo of Philodendron spiritus-sancti in situ growing up a tree
from Acta Botanica Paisagismo

Climate Notes for Espírito Santo, Brazil

Below data is taken from the climatic data available for Vitória, Espírito Santo, Brazil – a 50-minute drive from Domingos Martins

Temperature: Warm, Days: 25–31℃ (77–88℉), Nights: 17–22℃(63–72℉)
Humidity: ~75% year-round with minimal fluctuations
Rainy Days: 154/year
Note: based on this it rains on average about every 2-3 days; however, given the wet/dry season, rain is likely more frequent in Nov/Dec and less frequent July/Aug) – source
Seasonal Variation: Yes
• Dry Season – July-Aug (less rain [est. 1.7mm or 1/15” per day] & cooler [av. 21.5℃, range: 18-25℃]);
• Rainy Season – Nov-Dec (more rain [est. 6.7mm or 1/4” per day] & warm [av. 26℃, range: 21-31℃])

Annual Weather Data from Espírito Santo, Brazil
weather-and-climate.com

 

Philodendron spiritus-sancti Overview

A rare and highly coveted species among aroid collectors, Philodendron spiritus-sancti has attracted a lot of acclaim for its unique look, rarity, and its historically high price. The sword-like leaves almost look inspired by a Kori Blade. The plant can get huge with wild specimens reaching 20m (65’) tall and individual leaves exceeding 60cm (24”) long.

Photo: spiritus-sancti sword-like leaf on young plant

 

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Often referred to as “the holy grail of philodendrons” and “the crown jewel”, this unicorn plant has also been the source of scrutiny, scandal, and suspicion (mostly related to the price tag attached) with some sellers having to get DNA tests to prove authenticity of plants.

My goal in writing this post is to share cultural information on this species (because there isn’t a lot of experiential information available at the time I published this article) and I predict it will become more accessible in the future. I also just want to explore its care as a houseplant (that is…growing it in my less-than-ideal apartment conditions here in Canada, where my humidity averages 20-50%). In literature it’s regarded as very challenging, hard to grow, and slow, but I’m hoping success is related to culture like light intensity, water quality and nutrients rather than humidity alone—but time will tell.

My spiritus-sancti

 

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This article is brought to you by philomania.ca who had sent me a large seedling back in November 2021. I am thankful for the opportunity to grow the species, test my theories, and bring those findings to you. If you want to see the history of my plant, I’ve started an Instagram story tracking its progress starting the day I got it – click here to see that. I have also included some progress photos at the bottom of this article. Now back to learning about PSS…

The species name is written “Philodendron spiritus-sancti” [source Kew.org] (which is often written incorrectly, “Philodendron Spiritus Sancti”) – take note of the lower-case name (after the capitalized genus name) which indicates a species (hybrids are written Upper Case, and cultivars or clones are written ‘Upper Case with single quotes) and also note the hyphenation.

It’s a critically endangered species as a result of habitat loss and there are currently only six known wild PSS specimens. As a result of its prized value, cultivated plants span the globe in private collections because of the diligent work of nurseries and hobbyists who have propagated and distributed their plants. In recent years (as the plant hobby has blossomed to mainstream interest) Philodendron spiritus-sancti has also become the focus for breeding and tissue culture—which is amazing!

 

A Brief Taxonomic History

Summarized from Aroideana’s Vol. 24, “Notes on a Wild Population of Philodendron spiritus-sancti (Philodendron ‘Santa Leopoldina’)”: Philodendron spiritus-sancti was formally described in 1987 by George S. Bunting; but had been written about as early as 1983. It belongs to the subgenus Philodendron, section Calostigma, and while Bunting had classified it into the subsection Macrobelium, that group was later divided into four subsections by Croat in 1997. It seems taxonomists don’t feel PSS fits within any of those subsections now (E.G. Gonc.)…so, at this point there is a recognized alliance of species, but spiritus-sancti isn’t classified to a subsection (so far as I could find).

After its initial description by Bunting, a wild population of Philodendron spiritus-sancti was later discovered in 2000 on the property of Antonio Carlos Kautsky—this was close to Domingos Martins in the mountainous area of Espirito Santo. Those plants are now guarded and protected 24/7.

 

Spiritus Sancti Common Questions – FAQs

Note: If you have additional questions not answered here, send it to me via Instagram and if I can answer it, I’ll add it here too.

Why is Spiritus Sancti expensive?

Historically, it’s been expensive because it’s rare, slow growing, and hard to propagate; then it became highly coveted by a broader community of people and that drove the price higher. High prices are not uncommon in the plant hobby though—when Phragmipedium kovachii was first discovered, plant divisions sold for $10K+, and the same goes for Monstera Burle Marx Flame which has exceeded $12K for larger established plants. The risk of cutting a rare and expensive plant is high for the owner and some PSS plants have crashed after being cut for propagation. On top of the risk, they’re just slow-growing plants (unlike other fast-growing species like Monstera adansonii), so the time it takes to get 3 plants from one PSS plant is significantly longer than your more accessible species. So for all these reasons spiritus-sancti has commanded a very high price.

How much is a Philodendron spiritus-sancti?

Not a simple question to answer and is like asking, “how long is a piece of string?”—so the answer is, “pretty long”. It is rare and therefor supply has been limited. Not only should you account for the size of the plant, but demand influences availability (and subsequently price), so its price is variable but high. Historically, large specimens have been as much as $20K; however, smaller tissue cultured and seed grown plants are becoming available at a fraction of that price. As of Jan 2022, you may find small seedlings plants for as little as a couple thousand dollars.

Where are philodendron spiritus-sancti from?

Eastern Brazil in the Espírito Santo province.

What is a Spiritus Sancti?

It’s a rare type of tropical climbing plant called, “Philodendron spiritus-sancti”; the name is adapted from “Spiritus sanctus”, which is Latin for the Holy Spirit or the Holy Ghost in Christianity.

 

 

Philodendron spiritus-sancti Care & Culture – Indoors

Note: the care information here is based on research and my early experience growing this plant—I will update notes here over time. If you’re growing in a greenhouse, extrapolate as you feel necessary but beware I grow my plant indoors under dry conditions. I’m also going to assume this isn’t your first plant and therefore we’re glossing over some foundational details. If you want to know more about my Aroid care, please see my intro article on that topic.

Potting mix – treat like other hemiepiphytic philodendrons. Use a well-draining but moisture-retentive mix in a pot that always has drainage holes. For my plant I used my standard blend of Aroid mix and then added an additional half of bark plus some sand; my recipe is as follows:

Philodendron spiritus-sancti potting media
    • 6 parts bark
    • 3 parts pumice (or other inert well-draining material like large perlite or LECA)
    • 3 parts peatmoss (or other moisture-retentive organic media like fragmented sphagnum, coco peat, or tree fern)
    • 1 part horticultural grade charcoal
    • 1 part silica sand


Photo of spiritus-sancti potting media

The goal with a multi-part potting media like this isn’t to overcomplicate things and if you already grow a lot of Aroids, use the media you’re comfortable with. Instead my objective is to build a media that holds water while concurrently allowing ample airflow. A peat-heavy potting media (like your classic tropical potting soil) will hold lots of water but the density of the media can reduce airflow and with a plant like spiritus-sancti (which is highly epiphytic and adapted to life above the ground), it’s best to provide lots of airflow at the root zone to avoid rot which will set the plant back.

Initially after potting into this mix, you may need to water more frequently (twice a week for the first 2-3 months) as the plant establishes roots and as the bark ages and water logs, but the porosity of the media should allow ample airflow and prevent rot. Once established, you’ll likely only have to water once a week and may be able to push that to every 10 days. Also, when using a very chunky mix like this, if you’re finding it dries out too fast, it can be helpful to soak the pot and roots for up to 20 minutes on your watering day—a large bucket works for large pots or a bowl for smaller pots; however, just make sure that after you are done watering/soaking, that you fully drain the pot and avoid letting the base sit in water for the remainder of the week. Roots which stay in stagnant, wet and oxygen poor conditions for prolonged periods of time are at higher risk of rotting. I put a few pop bottle caps under the pot to ensure maximum airflow into the bottom drainage holes.

I also add a thin layer of sphagnum moss on top of the bark-based media to help increase moisture retention at the top layer of pot. Without the sphagnum layer, you may find the top dries faster than the lower layer and you may get less even root growth if your humidity is low.

Watering & Plant Hydration – Keep the plant hydrated…that’s my advice. Plants adapted to continuously humid conditions (like spiritus-sancti where humidity isn’t heavily variable season to season), may be less likely to have the adaptations to withstand extreme conditions like severe drought. It often means they do better with continuously moist roots, but you don’t want to smother them with a dense potting mix. Using a chunkier potting media ensures the roots have lots of oxygen in an effort to reduce the chance of anaerobic conditions (and subsequently root rot); however, it also means as a grower, you need to be diligent and avoid prolonged drought or missed waterings which is easier with an airy potting mix that dries out more quickly than your classic options.

Humidity: High humidity (70-80%) is likely the best target based on the climate this species comes from. Higher humidity helps to reduce hydration stress on your plant by limiting the rate of transpiration (water loss through the leaves), so it makes sense to offer that.

My humidity however, is below 50% and I don’t run humidifiers. The spiritus-sancti hasn’t shown signs of hydration stress and I also grow some of my more challenging plants (see Begonia pavonina, and Microsorum thailandicum) like this. Instead of adjusting my ambient humidity, I water on a very strict weekly schedule. This gives my plants consistency without severe stress. But to water on a schedule like this, you MUST use a well-draining potting media that dries predictably and if you use a different potting mix, I do not recommend scheduled waterings. The result for me with routine waterings is a more robust root system that helps mitigate water lost via transpiration. This schedule helps me keep my plants adequately hydrated despite the low humidity and it ensures I don’t randomly forget to water any plant in my collection. This is just what I do; it is not a recommendation for how you should treat your plants. Also, some plant species simply cannot tolerate low humidity.

A large spiritus-sancti at Ecuagenera’s Amazon Basin nursery where,
the humidity ranges from 60-100% depending on time of day

Water Quality & pH – This species is hemiepiphytic but grows mostly with the bulk of its roots attached to or hanging from the side of trees. This means it mostly receives rainwater on its roots rather than ground seepage. Rainwater is very pure <10ppm TDS, and is slightly acidic with a pH of 5.5. You may have better results using rainwater, distilled water, or reverse osmosis water (RO), and feeding lightly at ¼ strength the general recommended dose. From the IAS Newsletter on A Successful Pollination of Philodendron spiritus-sancti, the author notes that he grows his specimen using only reverse osmosis water in a poly tunnel with 70% shade.

For now, I am using tap water (150-250 ppm CaCO3, 7.9pH) which I acidify to 6pH every 3rd or 4th watering with pH Down by General Hydroponics. Lowering the pH can improve nutrient availability and subsequently nutrient uptake in plants. I don’t know that I would recommend this to others because tinkering with water chemistry is more of an advanced topic, but it’s what I do for my plants and so far, after the last seven months, my sprititus is doing quite well with the tap water and this routine. Again though, I will update this post over time as my spiritus-sancti progresses.

Fertilizer & Nutrients – Unlike all of my other Philodendrons which come from the western side of South America (along the Andes Mountain range), spiritus-sancti comes from the Eastern side. This has me a bit out of my comfort zone because I’m not familiar with the soil composition in Espírito Santo, Brazil—nor could I ‘dig up’ much information on this topic. Why soil composition matters: it could influence the tolerance of a species which is adapted to a specific set of variables (like minerality or availability of certain nutrients). As an example, plants adapted to iron heavy soils, often require more iron and low pH to grow well; conversely, plants adapted to alkaline soils need more calcium and neutral to slightly basic pH. So at this point I’m unsure if this species has any specific needs with regards to nutrient balance and/or pH.

My assumption is that a standard fertilizer routine will be acceptable and it seems others who grow PSS agree. I will be using the same fertilizer routine I have for all of my Aroids: every second or third watering (when I acidify my water) I use soluble MSU orchid fertilizer (which has nitrogen in the form of nitrate rather than ammonia), and then a few times a year, a dose (1/8 tsp) of my organic fertilizer mix (composed of an equal-part blend of bloodmeal, rock dust, and insect frass) into the soil. Again, I don’t know if I can recommend this at this point, so this is me telling you what I’m doing.

Light – In general I believe Philodendrons can take more light than most other Aroids. Their growth style is to climb a tree, reaching for light, and then unfurl the largest foliage where they get the brightest light—just under the upper canopy and sometimes fully exposed. At that point they can capture enough energy to flower, produce fruit and seed. That said, “bright light” does not mean full sun. In highly tropical climates, the skies are often cloudy, and that cloud (and humidity) disperses and screens the sun. So, with these considerations, I grow my plants at around 5-25% filtered direct sun equivalence and that’s broadly what I recommend to others. That means about 100 PPFD (PAR) up to about 500 PPFD (PAR) or 500fc to 2,500fc; typically, I’ll give them the upper range for about 2-4 hours in the morning (as direct sun through my windows), and then the lower range for the rest of the day (via LED grow lights). This is an advanced topic though because people often tell me, “my plants burn under light” without considering spectrum and the daily light integral (DLI)…so if you want to read more on light, see this article.

If you don’t have a light meter, the slower process is to judge light by how your plants react, grow and how the leaves look after a few weeks. The leaves should be a green-grey under higher light. Slightly yellow can indicate too much light (or just the result of a new plant with short/unestablished roots). In some cases chlorosis (yellow leaves from the upper range of light) can be remedied by proper fertilizing…but if yellowing continues, reduce the light intensity or the photoperiod by a few hours. If the plant is leggy, or producing smaller leaves (despite having a good root system) the light is probably too low and you should gradually increase.

As with all plants beware: excessive heat on dark leaves can irreversibly burn them, so if you’re growing near windows pay attention to seasonal changes to light and temperature.

 

Philodendron spiritus-sancti Morphological Differences

Leaf variation: wide vs. narrow leaves – the broadness of the leaf can be variable. On my plant there have been both slender and wide leaves, and this seems common if conditions are variable (warm/bright/dry vs. wet/dark/cool). This may be related to light intensity, humidity, or temperature -not sure which one- I will need to grow the plant longer to really assess what conditions influence the leaf shape—genetics and variation may likely also play a role.

Photo from Acta Botanica showing one of their PSS with 3 leaves on the same plant

Leaf variation: red vs. green – I haven’t found the full detail on this topic yet. However, in many other plant species, red leaf and flower color normally comes from the expression of anthocyanin pigments in the tissue—an adaptive trait to withstand high light. The expression often varies among individual plants of a species, and some can produce none, while others produce lots (kind of like how some people tan easier than others). Even if a plant has the potential to produce anthocyanin, it may still need specific conditions to stimulate its production (like excessive red-spectrum light)…so this variation of color is often firstly related to genetics, but then also to conditions. From my work with orchids, some plants grown under higher light in combination with cooler temps may express more color…but it’s not always the case and sometimes the reverse is true.

When it comes to leaf variations and spiritus-sancti, this is one aspect that makes seed-grown plants (as the result of cross-pollination) more enticing than tissue culture—but we’ll get to that topic further down.

 

Flowering & Pollination

Until recently, successful pollination of spiritus-sancti had not been achieved and therefore wasn’t documented. However, with the rise of aroid popularity around 2019, an abundance of information on general Aroid pollination had become more accessible, and finally in 2020 and 2021 two people had successfully pollinated a spiritus-sancti, producing viable seeds.

Photo of spiritus-sancti fruit
Acta Botanica Paisagismo

Pollination is generally the same as other Philodendrons and is challenging because of the inflorescence’s short fertility period, coupled with the plant’s offset of male pollen creation from the female receptivity. The plant must be pollinated during a narrow window at night (which may only be a few hours one or two nights in a row). The spadix heats up to attract its pollinators and this is when the plant can successfully be pollinated. The pollen is produced at the top-half of the spadix—after the cluster of female stigmas (lower half of the spadix within the floral chamber) are no-longer receptive. This two-step process prevents auto-pollination (self-pollination), and if you only have one plant, it’s clear why the species can be so challenging to pollinate, but it’s not impossible.

If you want to know more about the spiritus-sancti pollination process, there’s an article in the IAS Newsletter (Vol. 43 No. 4 – December, 2021) titled, “A Successful Pollination of Philodendron spiritus-sancti”, which you can access with an IAS membership for $30USD. The author of that article has also created a video and you can watch it on YouTube.

 

When does spiritus-sancti flower?

November/December or near peak summer temperatures. According to Aroideana (vol 24), spiritus-sancti flowers locally during November and December. However, if we look at seasonal climate variation in Espírito Santo (Brazil), December is the height of the rainy season, where total monthly rainfall is at its peak, where the temperatures are approaching their annual maximum in February/March, and where daylight hours are at their lowest. It is possible that warming temperatures or something related to seasonal changes signal flowering for this species, which could explain the July flowering time seen in some cultivated plants in the Northern Hemisphere.

The other primary influencing factor to get a spiritus-sancti to flower is likely just size and age of the plant—larger and more mature plants will produce more flowers because they can capture more energy from the sun.

 

Tissue Culture Philodendron spiritus-sancti

This topic always gets unnecessary heat from the plant community, so it seems valuable to cover in this article because TC spiritus-sancti plants are in circulation.

Firstly, the fact that spiritus-sancti has been tissue cultured should be embraced and celebrated, not shunned. TC in combination with seed-grown plants is how we will get a sustainable lineage in cultivation over the following centuries; otherwise, we risk exhausting the genetics from self-pollination and inbreeding. There are only a handful of genetically-unique PSS plants in cultivation, right? So, the more tools we use to protect the original genetic material and diversity, the better. TC is one way to ensure the most robust genetics are captured and shared from first-generation plants.

Secondly, if you’re one that thinks TC plants are somehow inferior, you’re wrong. TC plants are as good as the material used to create them; if a lab uses virused tissue, the props will be virused; if they use old, exhausted tissue, the plants will reflect that. That doesn’t mean tissue culturing produces inferior plants; it means we need to make sure the lab work done is careful and well executed. If you’re a vendor, seek TC plants from reliable labs or home-propagators that don’t cross contaminate their tools or use old plant lines. As a consumer, make sure the plants you buy look good and appear healthy; if a plant looks virused, don’t take the risk.

On the topic of virused plants, technically as a result of TC (through a very laborious process), “clean” tissue can be selected from virused tissue to produce uninfected plants – that is fricken cool, right? Yay tissue culture. If you want to know more about obtaining clean tissue from infected plants, refer to the book, Orchid Propagation: From Laboratories to Greenhouses—Methods and Protocol by Yung-I Lee & Edward Chee-Tak Yeung, Part III – Chapter 14, “Virus Elimination Through Meristem Culture and Rapid Clonal Propagation Using a Temporary Immersion System”.

 

My Philodendron spiritus-sancti (Photo timeline)

 

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It’s been about 5 months – got a few new leaves now which are much darker (yay) – Apr 6, 2022
The first new leaf emerged about 5 weeks later – Dec 31, 2021
Freshly repotted spiritus sancti – Nov 23, 2021
Placed over drainage layer to ensure maximum oxygenation at the lower level – Nov 23, 2021
Roots after arrival; repotting next! – Nov 23, 2021
Newly arrived spiritus sancti – Nov 23, 2021

 

That covers my care tips on Philodendron spiritus-sancti. I’ve had the plant since Nov 23, 2021 and as with all my articles, I’ll be updating this as time progresses and I have more context for its care. If you’re looking for more info about spiritus-sancti, see the below resources.

Additional Reading