Before I get into the details of how I care for this plant, I want to be transparent about something that may have influenced my success with this Peacock Begonia. That is, I suspect there is a chance my plant—the ‘blue form’ Begonia pavonina—may be a hybrid, not the “pure” species. There is a research paper about the multilayer structure of Begonia leaves and one of the plants used in the study is Begonia grandis x pavonina. B. grandis is considered a “hardy begonia” and it has an upright growth style, rather than rambling like B. pavonina. As my plant has aged, the growth has become quite upright, branching above the substrate, and structurally it looks quite similar to B. grandis even though the leaves are very blue.
Photo of iridescent-blue leaves – can see why they call it a peacock begonia!
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Online you’ll see reports of “two forms” of Begonia pavonina: the metallic-green (and difficult to grow) type and a ‘blue form’ which is easier to grow. This latter ‘blue form’ seems to be very common in North America (compared to the green form) and it’s sold on a few online shops. Intuition tells me that this “easier blue form” is actually the hybrid I mentioned above, and that’s why it’s easier to grow. In the orchid hobby this is referred to as “hybrid vigor” and it happens when a hybrid is made of two difficult species. The progeny inherit a greater range of genetic traits than either species along, and thus are able to survive in a broader ranges of conditions than either parent. If you consider for example that one plant is adapted to grow in alkaline soils, while the other has a faster growth rate, then a hybrid of those two plants could result in plants that are both tollerante of alkaline soil AND grow quickly. If you’re interested, I’ve covered more of my thoughts comparing traits in my plant to traits in the species pavonina down at the bottom of this article. If you have the ‘blue form Begonia pavonina’, you should still find this article helpful.
Reader beware: if you have the “green form” of pavonina, apply information from this care sheet at your own risk.
About Begonia pavonina
This is a neat species of begonia, native to Malaysia from at high elevation (1400–1800 meters), lower-montane rainforests. I could not find any secondary sources to reliably confirm this exact elevational data, but this would indicate that they require cool nights.
Under normal light, the leaves are green in color; but if you catch them at the right angle, or if a light source is nearly right near your eye, the leaves reflect-back an iridescent green-blue color with an almost holographic-like vibrancy. This perceived coloration is the result of a special adaptation to survive in low light and how the plant bends light in the cells. The chloroplast slow light down in specialized structures which allows the plant to efficiently utilize 10% more energy from sunlight (compared to standard plant chloroplasts/leaves). If you want to know more about the details of this, check out this great article by Bonnie Enos over at Everything Backyard. It’s also reported that under high light or specific light spectra the leaf becomes less iridescent and can lose the blue sheen.
The growth style is rhizomatous and the plant creeps along the top of the substrate branching as it ages like many Rex begonias. Leaves can be up to 6″ long. The petioles are hairy and the backs of the leaves are a deep crimson red.
Photo of my plant under regular light
Notice the leaves aren’t blue under regular light. To get that good iridescent color, the plant must be grown in lower light, should have some natural sun, and the angle of your vision (or camera) must be almost exactly the same angle as the light shining on the plant—the blue color you see is the light reflected back at you from the cell. For maximum effect, look at the plant with the light source near your eyes, pointed at the plant. With a camera flash or flashlight, the blue may be most obvious, but under the right light, you’ll still catch hits of the hologram-like colors from different angles as well. It’s a stunning plant to see in person and the camera rarely pickups all the color.
Begonia pavonina Care & Culture
Temperature – this is probably the most important aspect of culture next to your standard begonia care. Plants from high elevation habitats like Begonia pavonina are adapted to unique conditions which include cooler nights, more volatile humidity and potentially higher UV indexes. The atmosphere “up there” at higher elevation is thinner, less dense and doesn’t trap heat like it does at lower elevations. For this reason, Begonia pavonina (a high-elevation species) is considered a “cool grower”, but that’s a “tropical cool”, not “Canadian cool” and means it needs evening temps to go down from daytime temps by about 8C (but no lower than about 12-15C). Daytime temps should be “tropical” and should sit around 20-27C. According to Araflora, “A drop in night temperature also has a beneficial influence.” [source]
Plants adapted to higher-elevation climates like this have a different metabolism than “lowland plants” and rely on those cooler nights to throttle their consumption of sugar during the night. If you live in a continuously hot climate, this species may be challenging for you to grow.
Humidity – most articles say, “no lower than 50%”; a LOT say that it must be very high. My humidity sucks, around 35-50%, but my plant grows fine and I grow it like a houseplant. I am careful to water as the media dries and never let the roots go bone dry.
Begonia Potting Media – You’ll want to use a potting mix that holds moisture, but allows for good airflow to the roots and then you want to avoid letting the potting mix go bone dry (especially when acclimating new plants). I used peatmoss and large-chunk perlite at a 1:1 ratio, but what you use isn’t as important as how it works with your climate and watering method. You want the roots moist, but well oxygenated—as with all things horticulture and plant care—how you make that happen is very free form. When repotting, I always use a small amount of organic fertilizer which I’ll cover down below—this plant comes from limestone regions, so if your water is very soft or low in minerals, you may also want to add a small amount of oyster shells (can get this at a pet store) to the potting mix (1/4 tsp per pot) or dose with CalMag monthly when you feed.
Watering B. pavonina – above I mentioned you want to keep the roots moist and because this species has a shallow root system, you may want to “top water” and liberally drench the surface of the potting mix until water runs out the bottom. Active irrigation like this will oxygenate the soil and helps prevent root die-back so long as your potting mix is airy and drains well. If the petioles and leaves droop, you may have waited too long to water; avoid this in the future as I suspect a harsh drying of roots could kill the plant.
I have a watering method I like – where I use a water bottle with melted holes in the lid. I reuse that water bottle for months, filling the bottle with a jug of water over and over and using that to water the plants – here’s a video of how I water so you can see for yourself. I’ll spray the surface of the media and the leaves of the plant to really drench it (like it’s raining).
pH – As with most tropical plants, you’ll likely want your water slightly acidic (5.8-6.5pH) which will improve nutrient availability to the plant. I use my tap water which is naturally alkaline (7.9pH, 250ppm CaCO3) and I’ll alternate weeks with ever second watering being acidified to a pH of ~6 using citric acid. On the weeks opposite of that, I just use my un-adjusted alkaline tap water.
Light – I’m going to be honest with you, I find this an annoying topic because it requires a significant explanation for precision and I think it’s a topic a lot of new growers struggle with—I know I certainly did. I could tell you, “low light”, but I think I’d be doing you a disservice AND it leaves so much to interpretation of what that actually means…AND it has a high chance for error. The most direct explanation I can offer is, “I give my begonia about 10-20% filtered direct sun”; which depending on how you prefer to measure light is roughly 1,000–2,000 footcandles or 10,764–21,528 lux or 8.6–17.3PAR. You can use full sun and filter out 80% of it, or you can build up to that using grow lights…but you can see what I mean when I say, “Light is complicated!”
If you want to know more about light, I’m not going to leave you high and dry. Read this article about Alocasia Dragon Scale and skip to the section on light because it clarifies some of those gritty details and should be helpful. Then, if you are still looking for more details about light, jump over to this article: Tips for Buying, Measuring & Evaluating LED Grow Lights, which has some good videos and information about light for plants. After that come back to this article and reread the section on light.
Fertilizer – Another fun and complicated topic! You can feed with a standard synthetic fertilizer with NPK values of around 20-20-20 at a reduced strength (generally around 1/4 tsp per gallon of water). BUT…my opinion is that for the best growth you should offer a buffet of plant food, not just “fast food”.
Organic fertilizer offers a better range of plant nutrients. I add a sprinkle of bloodmeal, rockdust, kelp and greensand into the potting mix (1/8 tsp total for all of this – so just a tiny pinch of each) when I repot, and then 2x more per year, sprinkled on top. Organic fertilizers breakdown in the soil over time, so they’re NOT water soluble – this means you add them directly to the potting media, not when you water.
I still fertilize with synthetic nutrients every second week – I use MSU Orchid Fertilizer at 1/4 strength
More Begonia pavonia Care Resources & Articles
- Araflora, Begonia pavonina Caresheet
- Everything Backyard, The Mystery of the Blue Begonia and How to Grow This Shade Flower
- Strange & Wonderful Things Blog, Begonia pavonina Care
Photo Timeline of my Begonia pavonina
March 2021 – I’ve grown the largest Begonia pavonina I’ve ever seen
Comparing the difference with camera flash and without
January 2021 – Begonia pavonina blue-leafed plant
Early Plant selfie for size comparison
Peacock begonia flowers
Back of leaves and stems
Night photo with flash – Nov 12, 2020
Updated photo – it’s huge considering I’ve only had it for 2 months – November 11, 2020
Size increase and showing off that blue leaf – October, 2020
For the first 3 weeks, I kept an inverted pot over top to keep the humidity up. It grew so fast, I had to take the “mini-terrarium” off and it grew just as fine without. – End of September, 2020
The day my Unicorn plant arrived – September 11, 2020
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Hybrid or Species? Two forms of Begonia pavonina
I covered some of the main points at the intro to this article; however, there are a list reasons I’m suspicious that the blue form of B. pavonina is a hybrid:
- It’s very easy to grow (as mentioned). I grow it at a humidity below 45% like a houseplant and it’s weedy; that doesn’t align with “common perspectives” about Begonia pavonina being a very difficult plant.
- It has some morphological differences in the leaf shape, growth style, color, texture, and size:
- The petioles are smooth; reportedly true pavonina has hairs on the petioles
- The leaf edge is lightly serrated; true pavonina seems to have a near perfect reverse teardrop shape
- The leaf texture is “pillowy”; true pavonina has a mostly flat leaf
- The leaf color is blue and is iridescent under specific light or conditions; true pavonina is metallic green and extremely iridescent…you don’t need to hunt to “find the angle” to see the iridescence
- On large mature plants, the growth lifts off the ground and becomes branched; true pavonina is creeping and rhizomatous
Here are a few photos so you can see for yourself…
Extremely Vigorous – Before/After photo of my Begonia pavonina – 2 months growth
Upright growth that branches more like B. grandis
Compre to a photo of a true Begonia pavonina
An in situ (wild) Begonia pavonina – Image by Ong Poh Teck
Side-by-Side Photo Comparison of the two Begonia pavonina “forms”
The easier “blue form” (like mine) on the left and the true species on the right
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So…what if it is a hybrid? Then, honestly I don’t mind—I love the plant, how it looks and that it’s a fast/easy grower. I would love to just take credit and say, “I grow this amazingly difficult plant very well” – but I just don’t find it difficult and think others should know that.
I’m not a taxonomist or Begonia expert—I only have 2 begonias. I’m just a guy who grows and breeds orchids and I pay attention to small details in plant traits—like leaf shape, color, flower form, etc. Looking at the photos above, you might agree that there are some differences, maybe you don’t. I’m still sharing this information in the hopes that it’s helpful others. If you’re a taxonomist and you have disagreements with me, contact me via Instagram and let’s discuss your perspectives – my goal is not to spread misinformation, but to be transparent about observations.