Mr Straw's House Opuntia

[atgamble]

Hi all, hoping for some advice regarding a cacti collection and an old Opuntia that has become my responsibility. I work for the National Trust and one of our satellite properties is Mr Straw's House in Worksop. The Straws donated their house to the NT and it was taken on because it was almost untouched inside with regards to decorating and facilities. Walter Straw collected cacti, so they are an integral part of the collection and are housed in the greenhouse outside, which is in the original position although I imagine by now it's a ship of Theseus sort of situation, having been repaired as needed.

There is a nice collection of cacti and succulents inside, although many are suffering at the moment with excessive damp due to some broken panes and minimal care this year due to lockdowns and furloughs. Of particular concern is the Opuntia below, which I'm told is part of Walter's original collection, so must be of a good age.



Is the base just the result of corking and age and salvageable? The right hand branch where one of the pads is rotted will have to come off I think, but the two pads above the rotten one could presumably be treated as large cuttings to bulk up the collection with more original material?

There's also this one below:



Again I'm assuming most of this is unsalvageable and it's best to split it up into prop material? I have zero experience with Opuntia so would appreciate any advice and tips on care if there is anything different from other genera.

On a brighter note I think this is my favourite of the collection:



Is it an Oreocereus? Very cool plant and a good size, in need of some tlc along with everything else.

There's a link to an album of photos I took today here, hopefully it will show if you follow the link as I've set it to a private album. It's not all pretty to look at but I'm going back on Tuesday to take stock of everything properly and dispose of anything that's beyond saving. I'm hoping even the mouldy plants will have clean material that I can save and propagate from. The bottom photo in the album is a panorama, so if you right click and press view image you should get a full resolution photo so you can see everything. If anyone sees anything particularly interesting please shout!

https://imgur.com/a/jlRvPry

[iann]

Looks like a Cleistocactus.

[Acid John]

Can you not switch the heater on to give the survivors a chance if they are too wet?

[atgamble]

Thanks Ian, that looks right.

John, when I say damp I mean more like cacti sitting directly under drips at this point. There's some large holes in the glass that should be fixed this season, in the meantime the heat would go directly out of the roof. I think the drip trays probably do more harm than good too, as when I went to have a look today one had filled with water and I had to move all of the plants out of it.

[edds]

It looks like the pots are pretty wet from the photos (damp areas below pots). I'm not very experienced in cacti compared to most on here but wet and cold is generally bad news. Can they be taken somewhere warm and dry?

If they need to stay at the house, can the broken panes get at least some polycarb panels stuck over them and a heater and dehumidifier be brought in to get it warm and dry out the compost? If they were wet through the recent cold spell I hate to think how they might get on.

[esp]

Unless we have another very cold spell this winter, I would expect that most of the damage has already been done, so long as they aren't kept in an ongoing wet state for the next few weeks. From the very nature of such a collection, i'd expect that pretty much all the remaining plants are tough and hardy plants well suited to surviving in the conditions they have been in - anything too delicate would have already gone.

The damage on the Opuntias looks to be old and healed, or else mostly just ongoing age related corking, I don't see any urgent need to do anything with them - overall they look healthy, albeit not in prime visual condition. The smaller Opuntia on the bench (O. basilaris) could do with cosmetic pruning.

Having had a look through all the other photos, it seems a few of the slightly smaller plants may have died (obvious dead leaves in photo 2 of the gallery, for example). In addition the curving columnar cactus (Trichocereus) in photo 6 looks very wet, and the Agave partly cropped off the front left corner of the same shot looks like it may have got wet in the crown and started rotting. If so, it may well already be beyond saving, or drastic surgery may be needed immediately. Removing these from drip (if they can't be fixed) would be most helpful.

It seems a couple of the drip trays seem to get flooded, whilst others stay dry. Can all the plants can be moved into a dry drip tray, or onto the higher narrow wooden shelving for now? I think most of the other Opuntias and Agaves will be relatively tolerant of a bit of cold and wet, but the Ferocactus about 3/4 way along the panorama may be appreciative of drying out.

Otherwise, I think "Don't panic!" is in order.

[atgamble]

Thanks Ed and Edward! I think you're right that the damage has been done by this point to be honest, but it's mostly the smaller succulents that have borne the brunt of it. We've got some transparent plastic in one of our sheds, so I'll fix up the holes in the greenhouse and open the door and vents while I'm there to allow some air flow.

I'll remove all the dead plants and bits next week and perhaps give the larger Opuntia a period of grace and have a closer look at the damage. Hopefully in a few months I can post some photos of a healthy and happy collection in a fully repaired greenhouse!

[fero]

Hello
The opuntia is robusta. And the one I have is remarkably hardy.. when the weather warms up make a cutting of the damaged arm.
If you are planning on keeping what remains. Get a book on caring for cacti..
Most of the plants I can see from the photos are tuffies so should come through.
Be careful off the second opuntia microdaisys. It has tiny spines really ichy if touched..
Being the national trust I'm sure there will be a wipround and the greenhouse will be restored in good order.
Happy growing.