rooting Pterocactus cuttings

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ohugal
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Joined: Sun Aug 18, 2019 10:45 am

rooting Pterocactus cuttings

Post by ohugal »

I'm about to order some Pterocactus cuttings this week. I find them really interesting plants, but seeds seem hard to locate. Also, I have no experience with sowing yet. Does anyone have any experience with rooting Pterocactus cuttings? Is there something is should pay attention to? Temperatures are dropping here. My cactusroom is now 15°C (59°F) and very airy. We maybe have one sunny day a week. Besides that is raining all the time.
Location
Antwerp, Belgium
temperate, maritime climate with mild winters and cool summers
hardiness zone 8a
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anttisepp
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Joined: Sat Jul 10, 2010 12:00 pm
Location: Suomi - Finland

Re: rooting Pterocactus cuttings

Post by anttisepp »

My P tuberosus roots as a weed. :)
DaveW
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Joined: Thu Dec 20, 2012 2:36 pm
Location: Nottingham, England/UK

Re: rooting Pterocactus cuttings

Post by DaveW »

They root OK. I have around 12 including most of the species, but like all tuberous rooted plants when rooting they appear to just sit there for a while not making much top growth until a tuber forms below the soil. Also, you probably know that unlike most cacti the flowers are terminal on the stems and when they fall off, they leave a cavity so that stem cannot grow further but often will put out a shoot or flower like an offset below.

Note the cavity in the stem end from last year's flower and a new stem and flower from the side this year.

Pterocactus-HPT-791.jpg
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The stems sometimes have a habit of drying up at the tips but if lost or broken off will usually regenerate from the root the next year since they are often deciduous in habitat. Very interesting plants, but most can hardly be described as show plants out of flower due to their straggly growth.

They do have quite nice flowers and stand cool conditions since Patagonia where most come from is a windy and cool place.

reticulatus01.jpg
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They are members of the Opuntia group, but most don't have aggressive glochids. A video here but marenae shown is not a Pterocactus and is from Sonora, Mexico, not Argentina. Pterocacti should be more common since segments detach easily, but still P. tuberosus is the one that falls to bits easiest, so is the most common.

https://www.youtube.com/watch?v=A6JYZIgGLwM
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ohugal
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Joined: Sun Aug 18, 2019 10:45 am

Re: rooting Pterocactus cuttings

Post by ohugal »

I read pruning encourages new growth. When and where should I do that? Do you cut at the base of a (leggy) side shoot? I have a P. tuberosus I got from a market while on holiday. The roots are healthy, but it just has one leggy shoot branching from the base.
There are the species I've purchased:
Pterocactus fischeri JN19
Pterocactus fischeri JN26
Pterocactus fischeri KFF1098
Pterocactus fischeri KP161
Pterocactus fischeri KP164
Pterocactus fischeri KP165
Pterocactus fischeri KP168
Pterocactus reticulatus
Pterocactus tuberosus DJF188
Pterocactus tuberosus f. lelongii
Pterocactus tuberosus JN966
Pterocactus valentini CJH404 (MK1072)
Pterocactus valentini DJF225
Pterocactus valentini DJF342
Pterocactus valentini JN20
Pterocactus valentini MK651
Location
Antwerp, Belgium
temperate, maritime climate with mild winters and cool summers
hardiness zone 8a
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ohugal
Posts: 409
Joined: Sun Aug 18, 2019 10:45 am

Re: rooting Pterocactus cuttings

Post by ohugal »

I received my order of Pterocactus cuttings yesterday. It was more than expected. :D I drenched the cuttings in a pyrethrine insecticide to be sure and place a fan on them for a day or so. The grower told me he grows them on a raised bed consisting of 10cm/0.39inch of sand on garden soil. When grown in pots he uses 1/3 sand (or more), 1/3 "common black flower soil" and 1/3 "soil from the garden". He prefers "molehill". Not entirely sure what is meant by that, but I can guess.
pterooverviewweb.jpg
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#1 P. valentini JN20
#2 P. valentini DJF225
#3 P. fischeri KP165
#4 P. tuberosus f. lelongii
#5 P. reticulatus
#6 P. valentini MK651
#7 P. fischeri KP164
#8 P. tuberosus DJF188
#9 P. fischeri KP161
#10 P. fischeri KP168
#11 P. fischeri KFF1098
#12 P. fischeri JN19
#13 P. valentini CJH404
#14 P. fischeri JN26
#15 P. tuberosus JN966
#16 P. valentini DJF342
Location
Antwerp, Belgium
temperate, maritime climate with mild winters and cool summers
hardiness zone 8a
DaveW
Posts: 7376
Joined: Thu Dec 20, 2012 2:36 pm
Location: Nottingham, England/UK

Re: rooting Pterocactus cuttings

Post by DaveW »

I have only found that pruning P. tuberosus makes it flower quicker since the rest usually flower OK anyway. The thin P. tuberosus most easily drops joints and would normally "self-prune" in habitat. As an experiment I left all the stems on my P. tuberosus to become bushy and it did not flower for a couple of years, but then started again and flowered normally unpruned. The difficulty is keeping the stems on in winter since P. tuberosus tends to self-prune anyway, which is why it is the most easily obtained.

If you wish to prune it in winter leave a couple of stems on the tuber a couple of inches long and it will usually put-up new ones when growth starts and flower immediately on them.

This is my P. tuberosa when I pruned it previously just leaving a couple of short stems on and it immediately produced some new ones and flowered that year.

tuberosus.jpg
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"Molehill" is soil from the mounds that moles make when burrowing underground, therefore fine soil rather like "wormworked" soil where worms have processed it for us. I understand from Norbert Sarnes who grows a lot of these plants he now uses a mineral based soil, though I find they are not that fussy and grow in most cactus soils.

You may find this free to download book on them by Norbert and Elizabetg Sarnes helpful. See their section at the end on "Cultivation and Propagation".

http://cactus-de-patagonia.de/wp-conten ... _SAR_E.pdf
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