Pterocactus

A more in depth look at individual cactus species, a new one is added each month -managed by Hob
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DaveW
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Pterocactus

Post by DaveW »

As nobody has put anything on for this month, how about Pterocactus, an interesting genus that should be grown more? We have had the more common P. tuberosus on before, but these plants are ideal for unheated greenhouses in the winter coming from cooler climes like Patagonia. They are seldom found on the show bench as whilst interesting they can be pretty ugly with their rambling growth and the fact that unusually for cacti the flower is terminal on the end of the stem, therefore once it flowers that stem has a cavity in the end and can grow no further. It needs therefore to either produce new stems from the base, or produce one from the side just below where last years flower was. They have an unfortunate habit with me of sometimes part of the stem drying up. Really a plant "only it's mother could love" out of flower, but perhaps that is what attracts me to them.

The plants are tuberous rooted, with often far more below the ground than above. Some like P. tuberosus also have the unfortunate habit of shedding much of their top growth in winter, as they do in habitat. In fact a way to get P. tuberosus to flower is to remove most of the top growth in winter when it immediately puts out new growth at the start of the growing season and flowers on it, a bit like pruning roses.

The flowers however are fairly attractive making up for their nondescript stems.

P. tuberosus
tuberosus.jpg
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P. reticulatus
reticulatus.jpg
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reticulatus2.jpg
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P. spec. Note the calloused cavity at the stem end where last years flower was,
Pterocactus-HPT-791.jpg
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There are a couple of articles on Pterocactus here:-

http://tephro.com/%22index.php?option=c ... Itemid=101\"

http://tephro.com/%22index.php?option=c ... Itemid=101\"
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mdpillet
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Re: Pterocactus

Post by mdpillet »

Very nice post - thank you. Are any of the species considered to be more difficult to grow than others?
DaveW
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Re: Pterocactus

Post by DaveW »

I have not found them hard to grow, as long as they get a cool winter rest. I remember seeing a slide show on Patagonia once with Austrocactus and Pterocactus growing near the shore and large icebergs floating past in the sea in the background, so they do get pretty far south towards cooler climates.

The problem can often be getting starts, since they are not that popular, therefore not offered much. Most of mine were sent me by a friend in Germany, but obviously CITES stops us sending cuttings out of the EU and seed is often not available. This was the only seedsman listing any I could find, but maybe others know of a source of seed since you can import seed from anywhere? Most of the seed is comprised of a very large disk like wing, hence the name pteron = winged + cactus, a reference to the unusual seeds. Like most tuberous rooted plants, both with cuttings or seed, they tend not to make too much top growth until at least a small tuberous root is formed.

http://www.adblps-graines-cactus.com/Gr ... -03-04.pdf

As said P. tuberosus (syn. kunzei - decipiens) is the easiest to obtain:-

http://www.columbuscactusclub.com/ptero ... piens.html

https://cactiguide.com/cactus/?genus=Pterocactus

https://rootgorelick.files.wordpress.co ... 19-221.pdf

http://llifle.com/Encyclopedia/CACTI/Fa ... s_fischeri

Some pictures also here if you click on the camera in the Foto column:-

http://www.tephrowelt.de/bestand/Pterocactus.htm
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mdpillet
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Re: Pterocactus

Post by mdpillet »

DaveW wrote:I have not found them hard to grow, as long as they get a cool winter rest. I remember seeing a slide show on Patagonia once with Austrocactus and Pterocactus growing near the shore and large icebergs floating past in the sea in the background, so they do get pretty far south towards cooler climates.

The problem can often be getting starts, since they are not that popular, therefore not offered much. Most of mine were sent me by a friend in Germany, but obviously CITES stops us sending cuttings out of the EU and seed is often not available. This was the only seedsman listing any I could find, but maybe others know of a source of seed since you can import seed from anywhere? Most of the seed is comprised of a very large disk like wing, hence the name pteron = winged + cactus, a reference to the unusual seeds. Like most tuberous rooted plants, both with cuttings or seed, they tend not to make too much top growth until at least a small tuberous root is formed.

http://www.adblps-graines-cactus.com/Gr ... -03-04.pdf

As said P. tuberosus (syn. kunzei - decipiens) is the easiest to obtain:-

http://www.columbuscactusclub.com/ptero ... piens.html

https://cactiguide.com/cactus/?genus=Pterocactus

https://rootgorelick.files.wordpress.co ... 19-221.pdf

http://llifle.com/Encyclopedia/CACTI/Fa ... s_fischeri

Some pictures also here if you click on the camera in the Foto column:-

http://www.tephrowelt.de/bestand/Pterocactus.htm
Great stuff - thanks! Yes, P. tuberosus is by far the most common here. Would love to get my hands on a couple of nice P. australis clones. It's funny how Pterocactus is rarer here than in Europe, but the reverse is true for Cylindropuntia and many Corynopuntia.
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hegar
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Re: Pterocactus

Post by hegar »

Thank you, Dave, for entering the genus Pterocactus in the Cactus of the Month post.
I only do have one Pterocactus tuberosus and did have one or two flowers on it two years ago. It is good to know, how I can induce flowering.
One thing I found out about this plant though is the ease at which the broken off or shed pencil-thin stems will form roots. I already gave several of these rooted stem pieces away to fellow cactus collectors.
At our local cactus sales, this plant does not sell well, because it is not only straggly looking and puny, but also because it looks more dead than alive. :lol:
However, I am in the process of slowly moving into growing small cacti, because of limited space and the big guys just spreading out too fast, burying the little ones. That was one of the reasons, I decided to try the P. tuberosus. It certainly is a tough little plant and shrugs off our winters while in the ground in El Paso, Texas.

Harald
DaveW
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Re: Pterocactus

Post by DaveW »

As the nurserymen say Hegar you can't sell roots, it's how large the bit above the ground is that sells. One reason tuberous rooted species with little above ground growth are not seen in many collections, or in the trade. In the case of some underground tuberous rooted Other Succulents, in order to increase sales the tuberous root part is planted above ground to produce "pseudocaudiciforms". A trend started by some nurserymen when genuine caudiciforms normally having tuberous parts growing above ground were in short supply, therefore they "manufactured" some to satisfy the market. It has even been done with P. tuberosus, but it is not it's natural form of growth.

http://isladelpescado.com/item/succulen ... rosus.html

Yes Ptrocactus tuberosus is messy and does fall to pieces in winter time, particularly in colder climates like the UK, but that is normal in habitat too passing the dry season as mainly an underground root with a little top growth. Possibly that is why pruning back the top growth in winter encourages flowers, since it self-prunes due to wind and dryness in habitat.

The fallen pieces do root OK, but more or less stand still for a while until they have formed a small tuberous root. Something again that puts people off since they see little top growth at first. The P. tuberosus in my original picture above is an old plant I have had for decades and has produced loads more top growth than seen there, having shed it over the years. When I repotted it recently the tuberous root was spherical and two thirds the width of the pot, certainly a plant with far more underground than above. Strangely the other Pterocacti don't seem to shed their top growth in winter to any extent.

Somebody now has to come up with a new genus or species for November Plant of the Month?
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C And D
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Re: Pterocactus

Post by C And D »

I love the Pterocactus

P. tuberosus is great plant, the tuberus roots being one of it's best qualities.
This old plant has pounds of roots underneath the soil, I should repot it soon.
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I break some of the top strings off during the Winter to give it a more natural look.
I plant the cuttings which grow fat roots quickly, they always sell after propping up the roots above the soil a little,
You need a well draining soil to avoid root rot, otherwise they are very easy.
I have a couple other species as well.

I was able to do some heavy arm twisting to get Miles to sell me this P. australis.
Hoping to graft a head next year for propagation.
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Last edited by C And D on Tue Nov 28, 2017 4:00 pm, edited 1 time in total.
http://www.CandDplants.com

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Aiko
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Re: Pterocactus

Post by Aiko »

I ordered some Pterocactus seeds from ADBLPS this year. Have never tried the species. I also like the tuberous roots. There is not much more visually to be charmed about for regarding this species for most succulent enthousiast, I think...
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