Care Diary: Notocactus uebelmannianus, AKA Parodia werneri

Written byJen Greene

Animal lover, plant enthusiast, and addicted to the sunshine and warmth in San Diego.

May 19, 2021

Today, let’s talk about a cactus that is a dainty little favorite of mine: Notocactus uebelmannianus (try to say that 5 times fast), or Parodia werneri (much easier to pronounce). 

It’s a small, unassuming little species that is hardy, easy, and very forgiving of novice mistakes. Hailing from a small region in Brazil, in their natural habitat they are actually extremely threatened due to habitat loss. This can seem hard to imagine, considering how inexpensive and easy to find they are in the Northern Hemisphere, but they are bordering on extinct in the wild due to heavy habitat loss for agriculture and livestock cultivation. 

In the wild, they hail from the state of Rio Grande do Sul, in Brazil, which is a southern state bordering on Argentina and Uruguay. Most of the area these are found would be tall-grass prairie, if not developed, and temperatures can be quite extreme – 18F at higher elevations in winter, to 109F inland in summer. Specific data on the local growing conditions for these is hard to find, although the hardiness of the plants in domestic cultivation indicates that they’re unfazed by these significant temperature extremes. Despite the extremes, their usual weather is mild, with an average of 68F. 

Rainfall is relatively heavy for a cactus, with the region getting 52″ of rain annually – something to take with a grain of salt, as the state is relatively large. Assuming that little Parodia werneri likes tropical levels of rainfall is similar to assuming that San Diego native succulents (many Dudleyas, for example) need regular water, because the state of California averages 21.44 inches of rainfall a year. 

San Diego, on the other hand, is at best 12″ a year, and commonly as low as 6 – 9″ annually. 

So there is some uncertainty as to exactly how these might grow in the wild…but in cultivation, they are so easy and forgiving, it doesn’t really matter. 

notocactus uebelmannius

Plant Size & Potting Requirements

These are small, fairly slow growing cacti that you can commonly find at roughly 2″ – and they max out at 6″ in diameter. Above, you can see a photo of my first one in a 2.5″ pot, and it’s nearly as big as the pot, so we can call it roughly 2″. 

That was in 2019, and now, in 2021, it’s not a whole lot bigger! It’s maybe 3.5″ now, and that’s being generous. 

As far as what to pot them in, you could use straight Miracle Grow and this would probably be fine. For better growth and ensuring long term root health, you’ll probably want something better draining. You can mix in 25 – 50% perlite, vermiculite, or (preferably), pumice, and that should allow for enough drainage for this cactus to do well. 

Because these are fairly small, their roots are also small, although based on the plants I’ve uprooted and prepared for shipping, they tend to send out a pretty extensive network of fine, thin roots. You’ll want to pot them in a pot that’s only a little bigger than they are, or if you’re making the jump up to 4″ pot for a 2.5″ cactus, ensure that the soil is bordering on extra porous to ensure it drains and dries appropriately. Your biggest goal in cultivation is to allow the cactus’s roots to dry out quickly enough to prevent rot, but still allow for regular watering. 

I have my oldest specimen in-ground, where pot size isn’t as much of an issue as ensuring I’ve kept the area watered appropriately. 

Notocactus uebelmannianus

Light and Water Requirements 

If you look at the cactus pictured above (which may look familiar, as I just mentioned it in my “what’s blooming” post last week), you’ll see that compared to the original plant pictured, it has red blushing on the edges of the ribs, and long, intimidating looking spines coming from the center of the aeroles. 

These two things are both indicators that this cactus has been growing in more sunlight than the species usually prefers. Compared to the younger plant, the ribs are also much more pronounced, although not quite as much as a barrel cactus, to an inexperienced eye these might not even look like the same plant! 

Ideally, these get lots of bright, indirect light all day. They do well with 2 to 4 hours of direct sunlight in the morning or afternoon, when the sun isn’t at its peak, and this tends to be a light exposure that keeps them with the best green coloration and milder spine growth. 

When it comes to water, they thrive with regular watering compared to other cactus species, but still need to dry nearly or entirely before you water them again. 

I have several that share shelf space with my succulents that thrive with more light, and they are watered fairly often for cacti. In hot weather, over 90F, I may water almost daily, although in more moderate temperatures it’s more like once a week or so. 

parodia werneri monstrose

I have a handful of these cacti, and while the blooms are certainly my favorite part, my funky finds are also very neat. 

I was fortunate enough to find two sports at my nearby wholesale plant nursery, including the monstrose/crested form above. I’ve only had them for a couple months, so they are too small to bloom but have been showing signs of new growth since being potted up. 

notocactus uebelmannianus variegated

Above is my variegated Notocactus uebelmannianus, and you can see the brighter red spines of the new growth at the center. I’m looking forward to blooms next year, and hopefully seeds! 

To encourage your notocactus to bloom, you simply need to keep it happy for the year, and then each spring, it will reward you with a crown of brilliant flowers. Normally, flowers are a magenta or brilliant deep purple-pink, but there are some forms that produce yellow blooms. 

These are delightful, easy to grow, and small cacti – I hope you give one a try in your collection! The small roots make them easy pot companions with other unobtrusive species, although I’d caution against combining them with lithops, pleiospilos, or other mesembs due to how much water they prefer. 

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