Early review of affects of the cold snap

[Mike P]

Had time to visit the allotment and assess the plants in the unheated greenhouses and poly tunnels today following Decembers big freeze. The max/ min recorded -6 oC in one of the greenhouses.
Not surprisingly there were more losses amongst the succulents including a few Echeverias, an nice blue Agave macroacantha (surprised me as it’s been through several winters), a couple of Adromischus ( but not the A cooperi I keep as a canary) and a few Opuntias…..namely two C sphaerica clones, my grafted A lagopus ( mostly melted but half a dozen heads seem ok and have been rescued) and Cumulopuntia ‘mistensis’ ( turned to mush but half a dozen heads low down were fine and are now cuttings ) and Cumulopuntia ignotia ( again a few heads saved but main plant is mush). They were all dry but the Cumulopuntias were still somewhat turgid. The largest of the O sulphurea plants shed a lot of its pads but they and the main plant seem to be fine so will become cuttings for next year.
A leak in one of the greenhouses led to a few trays of seedlings being soaked but oddly they seem to be fine.

[iann]

Echeveria setosa, both big green and small blue forms, are fine, but I think this is one of the more hardy species. It never gives me problems unless it is too damp in autumn, and it can get botrytis. All attempts to keep it outdoors in winter have failed dramatically. The only other one I have is a very succulent strongly clumping plant that never flowers and is probably a cultivar. I would have thought not so hardy, but apparently I was wrong.

Something in the greenhouse is definitely dead, I can smell it, but I don't know what it is. I thought it might be a Haworthia I found under the staging, but it doesn't smell bad up close so maybe something else. The Lithops that look funny colours don't smell and none of the cacti seem to have been affected by the cold. Maybe it is just general mustiness from the condensation.

[Paul in Essex]

A lot of my newer, untested stuff I have planted over the last couple of years seems to have suffered. Some may recover, doubtless more will keel over in spring once they realise they are dead. My coldest temperature across the garden was -6C, which is the coldest I have seen here for over 10 years. But it wasn't the low temperature that killed outside plants off, it was those exposed to the freeze/thaw over a week where temps barely recovered to above freezing. I guess that is the nature of experiments - you always get results, just not necessarily the ones you had hoped for Then again, there are plants that look absolutely fine and dandy so tentatively added to my expanding list of garden plants. My 'stalwarts' are fine, though. Fingers crossed for a mild January and February! I'd also wish to become slim and handsome, which are about as likely

[Darren S]

I decided, due to lack of space, to overwinter a lot of my Opuntia and Echinocereus in an unheated cold frame, along with some other reputedly hardy plants in pots. All were dried off in October.

All the opuntia and Echinocereus are unharmed.

Agave utahensis and some young mckelviana look fine. A couple of other young agave look unhappy. An unknown Echeveria sharing an Agave pot is mush.

Aloe striatula looks ok. Aloe aristata next to it looks very unwell despite being allegedly hardy.

The Aloinopsis/Nananthus hybrids I have posted on here before are completely unharmed despite being rained-in on then frozen. Given the Denver provenance of the seed this is not too surprising.

[RayW]

First signs are not good, it would seem a few Cumulopuntias and Tephrocactus have turned to mush and like Mike I have taken a few cuttings of the bits that might survive, it seems to be the large plants that are the worst, cuttings and small plants of the same species look fine. ( well at this point in time anyway ).

[Mike P]

I think with the Opuntias this is because the larger clumps take longer to dry out and were still turgid although the roots were dry.
The Echeverias were a gamble anyway and were mostly sales plants I couldn’t house at home. The only one I am really cross about is my old Lagopus which I have had for many years.

[Phil_SK]

I accidentally left my Matucana madisoniorum out in the greenhouse a couple of years ago and it survived (I aim for 1C) so didn't really give it much thought this year. Greenhouse dipped a bit lower, to -2ish, with colourful results. A few other things look unhappy but should be OK.

[Herts Mike]

As it’s a decent morning for a change I’ve been able to check the outside beds.
As mentioned elsewhere Aloe striatula looks rough and we’ll have to see if it comes back in spring.
Lampranthus also may well have gone.
The Aloe polyphyllas look fine, a Manfreda looks to have survived but outer leaves have gone. Agave gentryi marked but fine, Agaves parryi, mitis, utahensis v nevadensis and eborispina are fine. Selenicereus spinulosus and Nolina nelsonii are fine. Echeveria Perle von Nurnburg a bit marked but looks ok as it was sheltered by a big Lampranthus.
Cycas revoluta leaves have mostly gone brown but I think the crown is ok.
And of course Disocactus flagelliformis looks fine as well!

[Smel]

Hi,
Yes I too have lost many plants with that very cold snap! I had intended to replace the cheap packing bubble wrap with the proper stuff, but never got around to it!! And has the last two Winters had not been that bad!
I spent sometime in the Greenhouse yesterday many of my Lithops were just bags of water! and Conos too. Many soft succulents Crassulas, Aeoniums and the like, some may recover I hope.

So first job for March-April get that greenhouse insulated!! with the right stuff, big bubbles, triple laminated ? Anything else, I should be doing??

I'm sure we will all come bouncing back, with new plants and lots of flowers..................

[edds]

I've lost all the Echeveria (cante and gigantea) I left in my unheated, cold and dark greenhouse.

I've also lost at least one Aloe polyphylla that were in there. These were in 2l pots and were 2 years old. The crown of the dead one has gone completely to mush. The others don't look good either. Bit surprised by that seeing as larger ones live outside wet and cold!

The three planted outside were covered in fleece. The largest looks ok but has damage to leaf tips, the 4 year old looks pretty good but the smallest, 3 year old plant, is looking ropey. It had some slug damage on autumn which hasn't helped I think.