Pterocactus tuberosus winter care

[Lorraine]

Hi, I have a young pterocactus tuberosus but have read of different ways to treat it in winter.
The fingers show no sign of dropping off by themselves so should I help them either by pulling or cutting or should I leave them to their own devices and see what happens as winter progresses. It usually lives in the greenhouse which is unheated so I have moved it into the house for the winter. Also should I give it a small drink occasionally while it is in the house ? With thanks, Lorraine.

[Darren S]

Hi Lorraine, there are more experienced Pterocactus growers on here who will doubtless chip in. But it should be totally hardy in an unheated greenhouse provided it is kept dry - in fact it will benefit from being colder than it will in the house.
Also - if young and not yet big enough to flower there is probably no advantage in removing top growth- I believe that the more top growth it has to start the next season with, the faster the tuber will reach flowering size.

[edds]

My plant is only a couple of years old but I agree with Darren re hardiness. I have spoiled mine, keeping it frost free for a couple of years, and this year it's going fully unheated to see if I can get the top growth to die off naturally in the hopes this will get it to flower.

[Cidermanrolls]

I grow them in my coldest greenhouse and am experimenting with some in a completely unheated cold frame.
There is no need to remove top growth, especially not on younger plants. I prune my mature plants every couple of years, cutting the stems to about 1cm above the tuber. This makes the plants look much tidier and is believed to encourage flowers.
Even in the cold greenhouse I start watering the Pterocacti in late February, gently at first, not a soaking and allowing the soil to dry out before watering again. I also watered in to November, again just gently.

[RayW]

I agree with the above posts, cold will not be a problem but damp might, as stated these can be watered earlier than most cacti.
Leave stems on the plant they will drop off if they want to. I leave all mine on the plant and it does not effect flowering.
See photo below I posted on the TSG sub forum a couple of years ago.

[Lorraine]

Hi thank, you all for your advice, I am obviously over mollycoddling mine. I will move mine into the coldest room for this winter but leave it in the greenhouse next year. I tried to upload a photo but couldn't get it to appear on the post. It would show 6 fingers about 3 inches long growing straight up so if they sprawled over while outside I would probably panic and think they had died !!

[habanerocat]

A very interesting cactus for sure.
Something different......

[DaveW]

All my Pterocacti come through the winter often below freezing in a cold greenhouse. P. tuberosus is not a plant for those who grow them on windowsill's or in their house since it drops some segments in winter making a bit of a mess. Otherwise it is easy to grow and due to dropping segments the easiest Pterocactus to obtain. However joints seem to stand still for a year or so with not much moving above ground whilst it forms the tuberous root.

Pruning the plant once the tuberous root is a reasonable size will promote flowering next year since it flowers on new shoots.

However for an experiment I left all the top growth on for about three years and for two it did not flower. However it started again the third year although it looked a mess. As you can see it's in bud but not really Show Bench material!

Pterocacti are unusual in that the flowers are terminal on the end of the stems and leave a hollow when they drop off. Therefore the stem cannot grow any further and has to produce a new stem and flower lower down the joint or flower from a newer stem.

Pterocactus HPT-791 showing cavity at end of branch from previous years flower and the next years flower growing out of the side.

[Mike P]

I grow most of my Pterocacti in an unheated greenhouse and do cut the top growth off P tuberosus as it leads to a more natural looking plant. In habitat they lose the top growth each year and grow new flowering stems from the tuber so what you are growing is in effect a flowering tuber. The exception with tuberosus is the monstrose form which never sheds growth but neither does it seem to flower.

[DaveW]

Yes in habitat the wind would probably have stripped most of the top growth off mine.

Its been posted before, but if you are interested in Pterocactus there is a free to download book by Norbert and Elizabeth Sarnes available in three language versions.

http://cactus-de-patagonia.de/literatur