Ariocarpus retusus: One fine day...kaboom!

It’s always great to start a new year with a big bang (in the positive sense of the word, of course). Our stock market sure started out that way but unfortunately has fizzled out and may be on a downward trajectory for the moment. The reason I was thinking of the stock market just now is because some of my broker friends like to use the phrase “One fine day…kaboom!” to refer to a stock investment which, in their minds, is undervalued, underplayed and unnoticed. They then slowly accumulate this stock, buying a little bit each day or week or month. Their hope, of course, is that one fine day in the future, market conditions will improve, the stock they’ve been accumulating actually has fantastic fundamentals, and investors will take notice and start buying it aggressively. And then, kaboom! The stock price goes through the roof, and the patient investor who got in early while nobody was looking makes a massive killing in the market. I know of a few guys who’ve done this before and come out on top. Of course, there’s also the flipside… sometimes it doesn’t go kaboom! but “kabust!”

I thought the stock market is an appropriate analogy with my experience with that beloved rarity, Ariocarpus retusus. This is a plant that I have been growing since I was a teenager. But while I have had some success cultivating this plant, I have never been able to flower it until only last year, after the plants had the full benefit of the better growing conditions of Tagaytay Highlands.  And then again, I only managed to flower three plants out of more than a dozen. I have had a lot more success flowering all the other Ariocarpus species. Needless to say, flowering an A. retusus has been one of my biggest frustrations in all my years as a succulentophile.

Then last weekend…kaboom, boom, boom! Suddenly and without any real notice, most of my A. retusus were in flower. And not just in regular flower — some had over 10 open blooms each! A. retusus ssp. panarottoi, named after the famed Italian cactus explorer and nurseryman Paolo Panarotto, topped them all with 12 white blooms. Next was A. retusus ssp. trigonus, the only yellow flowering Ariocarpus, with 10 blooms. And A. retusus ssp. retusus v. furfuraceus, a specimen that I obtained from California a few years ago, followed closely with nine open creamy-white flowers tinged with pinkish ends. What was especially nearer and dearer to my heart was my rare form of trigonus, the variety horaceki, which is a smaller growing form of trigonus. I acquired my plant over 10 years ago from a Japanese source. I have been able to flower this plant exactly zero times since. And yet over the weekend and in the proper growing conditions, this long-barren plant of mine decided to produce four golden yellow flowers! I must say I really started the year on the right footing — at least as far as my cacti are concerned. 

A. retusus is the largest and, generally, the fastest growing of the six or so species of this highly prized genus of Mexican cacti. A. retusus can attain a diameter of 10 to 12 inches in some forms. It is widely distributed in the Chihuahuan desert, from north of Saltillo, Coahuila southwards to San Luis Potosi. It also occurs in the states of Tamaulipas, Zacatecas, and Nuevo Leon.

As might be expected from its wide distribution range, A. retusus is highly variable. Tubercle size and shape vary widely; a terminal areole may or may not be present; flower color ranges from white to pink, or may even be bicolored. The range of variation has been further increased by the reduction of A. trigonus to sub-specific rank under this taxon. The vast amount of phenotypic variation in the species has led to the erection of several variants. A. retusus ssp. retusus v. furfuraceus has been applied to plants with equilaterally triangular-shaped tubercles. Other variants include A. retusus ssp. panarottoi, which has differently shaped tubercles. There is also a more recently described variant named A. retusus ssp. sladkovskyi. While resembling regular A. retusus, its tubercles are a bit more rounded at the ends and greener. But what I have noticed is that this plant flowers a lot earlier than regular A. retusus (for me, it starts flowering in November through December) and its flowers are light pink.

Possibly the most interesting A. retusus to come around in the market of late is the plant described as A. retusus ssp. confusus. It is a controversial taxon erected by Halda and Horacek in 1998 to indicate the plants of the Ariocarpus retusus/trigonus complex found in several locations around the Aramberri region of Mexico. These A. retusus are extremely variable in body form, and also in flower color. Aramberri is located in a valley between two mountain slopes. On either side of the valley one may find populations that look like the typical A. retusus while others resemble the typical A. trigonus, with a range of intermediates between the two. Morphologically, plants belonging to the confusus species resemble either the subspecies retusus or the subspecies trigonus. However, these are easily distinguished from either of these retusus sub-species by their interesting variation in flower color, which can range from white to magenta, a color not found in any other populations of A. retusus/trigonus. Bicolored flowers also occur. What I have also noticed is that in many of the more distinct forms of this taxon, the ends of the tubercles really narrow and sometimes curl upward or downward.

Given the right growing conditions, A. retusus is actually quite easy to grow. This species is slow growing but certainly not as slow as some other types of cacti. It takes anywhere from six to 10 years to grow a flowering plant. The key to flowering this plant is to have the right location, with lots of direct sunlight, free airflow, and protection from the rain. These plants must be grown in a well-drained, non-organic soil mix. I use up to 40-percent good sandy garden loam, with the balance in the form of washed builder’s sand, pumice and/or crushed volcanic cinder. To this I add some 14-14-14 slow-release osmocote fertilizer pellets. I water thoroughly once a week year-round. 

The main threat to their development is root rot. Ariocarpus plants don’t like to be standing in wet soil for extended periods. In my growing conditions, after I thoroughly water one day, I can expect the growing medium to be completely dry after no more than two days after watering. In addition, I never water my Ariocarpus from the top, as this will surely ruin one of their wonderful qualities — the wool they produce at their growing apex. I water around the plant without wetting the plant body. The chief pest is, unfortunately, the most dreaded of succulent pests in our part of the world, the hated scale. But there are quite a few ways now to eliminate scales without using harmful chemical insecticides. Just be vigilant and catch the pest before an epidemic occurs.

If you follow the above prescription, you stand a good chance of seeing your A. retusus flower in January (these flower in October thru November in the West), with the exception of subspecies sladkovskyi which should start flowering in November. Then you can regularly expect that one fine day to come rolling by on a regular basis. And best of all, there shouldn’t be any threat of a “kabust!”