Sempervivum calcareum is a species of Sempervivum that has been relatively popular for a while. Most of the calcareums that I have seen tend to look similar, being characterized by a whitish green with sharp, dark tips. I'm opening this thread for people to post pics and discuss their various calcareums.

I think that calcareums are a bit more fragile or sensitive to conditions than your typical Sempervivum. I know that I have lost several types of calcareums overwintering over the years.

Here is a partial list of the calcareum varieties, which I'll update from time to time as I hear about others. * means I have it in my collection, + means I am looking to add it.

+ S. calcareum (the species type)
+ S. calcareum ex Guillaumes (S. calcareum from Guillaumes, France)
+ S. calcareum 'Extra'
+ S. calcareum from Route d'Annôt, France
* S. calcareum 'Greenii'
+ S. calcareum 'Limelight'
+ S. calcareum 'Monstrose' (or sometimes 'Monstrosum')
* S. calcareum 'Mont Ventrox'
* S. calcareum 'Mrs. Guiseppi'
+ S. calcareum 'Nigiricans'
+ S. calcareum 'Nigrum'
* S. calcareum 'Oddity' (earlier name S. calcareum 'Grigg's Surprise')
* S. calcareum 'Pink Pearl'
* S. calcareum 'Sir Wm. Lawrence'
+ S. calcareum 'Spinulifolium'
+ S. calcareum 'Tip Top'

Once you've seen a few of the calcareums, you'll start to recognize the type. However, some caution is needed before assuming a cultivar is a calcareum as there are other Sempervivum species with sharp dark tips that can look very similar.

Below is a pic of S. calcareum 'Greenii' and a closeup of the same plants. I'll add some more pics in the future of the ones I have.

S. calcareum 'Greenii'

Here is my S. calcareum 'Pink Pearl'. I had trouble for the first time this year with losing most of them due to our very long wet winter and spring. But I did manage to save a few. I'm adding extra chicken grit for these. I really love this semp.

Here is my new plant S. calcareum 'Monstrosum'. Hopefully it will do well for me and I can send you some offsets next spring twit.



Edited on 9/8/2015
This semp has been sold by the name of S. calcareum 'Monstrosum', but it is the same sempervivum as S. 'Oddity' which is not a form of calcareum.

I would love to have one. I had one last year and lost it by the end of summer. It was doing OK for a while, but didn't make it to the end of the summer. I realize now that I did not have it in the best spot for the "fussy" ones.

Your 'Pink Pearl' looks white-ish and is very nice. Did I mention that some of the calcareums are known to get large? None of mine have ever done that, but I just started collecting them last year and haven't seen full size on some of them yet. I had a rescue calcareum two years ago that first attracted me because it was almost white. Of course, it was fussy and dried out too much over wintering.

Here's a picture of S. calcareum 'Sir Wm. Lawrence'. I think this one can get large and is sort of majestic in a calcareum way.

S. calcareum 'Sir Wm. Lawrence'

Your S. calcareum 'Sir Wm. Lawrence' is beautiful twit. I think I am falling in love with the calcareum now. I always did love Pink Pearl though from the firs time I saw her. She got about 4½" across. Not sure if she will get bigger than that. I will know next year as I have her in an area where she won't get crowded. Time will tell. I will work very hard at keeping Monstrosum happy and healthy, so we can both have them in our collections.

Here's another calcarem, S. calcareum "Mrs. Guiseppi'. It's a new one for me form a trade this summer, so I don't know much about it.

S. calcareum 'Mrs. Guiseppi'

Interesting how the two above photos almost look like the same plant, until you look at the foliage growth.

Most of the calcareums I've seen have been very similar. I'm just now getting a collection to compare over the next couple of growing seasons, if they remain hardy in this area.

I almost lost my S. calcareum 'Sir Wm. Lawrence' with all the rain we had this spring. Luckily it seems to have recovered. I'll have to be careful with it this winter too.

S. calcareum 'Mrs. Guiseppi' seems to be more of an open or loose than most of the other calcarems. Pretty!

Good point, but these are recently acquired relatively small chicks raised elsewhere. So, I'll be looking to see how they develop and mature with chicks of their own.

Here are my new baby S. calcareum 'Greenii'.

Your 'Greenii' are showing a lot more red than mine get. They look very healthy and happy! They make nice clumps.

We have had very cool nights all summer, and now even the day times have cooled down. I think it tends to bring out the red, also these are still kind of closed up so show more of the red tips. I can hardly wait until they have multiplied enough to make a clump.

WOW Love that S. calcareum 'Monstrosum'.

Holly, the little offsets are so cute in all their tiny, odd growth. This is my first year with this plant so will have to see how it does on making offsets. Hopefully I will have some extras to trade in the spring. They would be really cute in your rock wall.

That is very unusual.

What is unusual Jacki?

S. calcareum 'Monstrosum' - sorry, I guess that comment was kind of out there by itself

Sometimes you have to hit me over the head to get a comment across.
I have a hard time telling
S. calcareum 'Monstrosum' and S. tectorum 'Oddity' apart. Can anyone help me with that problem?

Those do look similar - I think on 'Oddity' the young leaves are cylindrical (cut one open - are they hollow inside?) and 'Monstrosum' seems to just have the downturned foliage. That will be interesting to grow them side by side and see the differences.