valleylynn said:So far all of my J. 'Feuerrad' grow on very short stolon, I have found non yet that have multiple rosettes from a single crown/root.

Peter, do you know why the Sempervivum and Jovibarba will not cross?

that's the difference between the nixonii-groups - Jowan is a x nixonii (x nixonii) and Feuerrad is a x nixonii (x smithii);

I don't know enough about genetics to understand why Jovibarba and Semps will not cross; I only know that there is no example where it works;

I wonder if @jungleshadows has an answer about why Jovibarba and Sempervivum will not cross. Seems like when I was at the clinic in the spring he said why but I don't remember.

Thank you Peter for the explanation.
Do you find J. 'Jowan' to be somewhat unstable in the way it grows?

I've had a lot of trouble with Jowan myself. I obtained it a few years back, and all of the rosettes that I had bloomed for me. So as soon as I noticed the blooms forming, I divided all of the rosettes and removed the forming flower spikes. Unfortunately all of the divisions eventually re-bloomed or died off with none of them ever producing additional rosettes. The exception was one rosette that earlier this year did finally, after a couple of years of doing nothing, form an extra rosette (or possibly two). However, the last time I saw it, it was blooming again. I'll have to track it down to see what as become of it. Hopefully its finally decided to behave like a plant that wants to survive.

Frequently when closely related plants will not cross, they have different numbers of chromosomes. This does not appear to be the case, but there is an apparent difference in the pollen shape between Jovibarba and Sempervivum, which might be significant.

The following article, although it gets a bit technical at times, does contain some useful information as well as speculations about this issue.

http://stalikez.info/fsm/semp/...

valleylynn said:
Do you find J. 'Jowan' to be somewhat unstable in the way it grows?

sorry - 'Jowan' is not part of my collection; I've only heard that it grows slowly;

other J. x nixonii - cultivars like 'Feuerrad' (not the sempervivum from Martin Haberer but the nixonii with unknown breeder) grows quick and stabel;

Twit, that is a very interesting article, thank you for the link. I read it through, but need to go back and study it more closely.

Peter, it is my experience that Jowan grows slowly, and that Feuerrad grows quickly and has never been unstable in growth type.

Lynn. That was a interesting article. I need to read and look up definitions so I can understand more of what is being said. Thank you, Twitcher.

twitcher said:I've had a lot of trouble with Jowan myself. I obtained it a few years back, and all of the rosettes that I had bloomed for me. So as soon as I noticed the blooms forming, I divided all of the rosettes and removed the forming flower spikes. Unfortunately all of the divisions eventually re-bloomed or died off with none of them ever producing additional rosettes. The exception was one rosette that earlier this year did finally, after a couple of years of doing nothing, form an extra rosette (or possibly two). However, the last time I saw it, it was blooming again. I'll have to track it down to see what as become of it. Hopefully its finally decided to behave like a plant that wants to survive.

Frequently when closely related plants will not cross, they have different numbers of chromosomes. This does not appear to be the case, but there is an apparent difference in the pollen shape between Jovibarba and Sempervivum, which might be significant.

The following article, although it gets a bit technical at times, does contain some useful information as well as speculations about this issue.

http://stalikez.info/fsm/semp/...

Thanks, Twitcher!

In Section 3.3.1 under the heading "Genetics", it appears the author is saying that crossing may be possible between Sempervivum and Jovibarba?

I saw that also Janice.
Hmmm, maybe we will all have to give this a try.

Janice do you still have some of this plant?? It sure is a nice one. I too thought it looked like a rosularia or something other than a semp. Don't know what their flowers look like though

sandnsea2 said:I agree with you, Chris, it definitely looks to be part Jovi and that is what I asked Youngs, if perhaps they had a mixup, which they assured me was not the case.
However.........

Based on what I see on Sempervivum Liste site and our database photos, this does not look to be Green Gables.
****Note the difference in the flower color on Liste site.
http://sempervivum-liste.de/Se...

(However, looking at the photo on the Young's website, yours looks exactly like their Green Gables, which does not look correct.)

Mine now looks like this, which still does not look like it should, so I think mistakes were made at Youngs, and we should label it a NOID.

yes here is the photo from farther up in this thread.

I've looked at this one from Young's and SMG and almost got it!! Now I'm even more curious about it!!

A couple of points I want to make for clarity here.

While I found the article very interesting as well, we need to all remember that the article is a translation from French, so it is possible that some inaccuracies due to translation can occur. Please be sure to read all of the other chapters when you can. There's a lot of good work and information there.

Regarding crossing between Sempervivum and Jovibarba, there is a nomenclature issue to keep in mind. Some authorities regard Jovibarba as not a species, but rather a subset of Sempervivum. So when reading discussions regarding Sempervivum X Jovibarba heuffelii crosses, please keep in mind that the "Sempervivum" involved could conceivably be another "Jovibarba" according to how the author is using the nomenclature terms. I am not current on what the proper nomenclature is these days, but always try to watch out for that possible ambiguity. Not my area of specialization, just being a hobbyist. I try as much as possible to go with correct names, but as a hobbyist, also try to use the best name I can to identity the plant in the hobby.

Regarding Green Gables, I had that a few years back from a trade, but all of the rosettes bloomed out without making any offsets. As I recall, the plant was a bit unusual in that the blooming occurred over a two summer period. The plant had a "crowning" shape the first summer that I could not be sure was preparation for blooming, but the second summer that became clear as the plants all bloomed.

Thank you twit, I will keep that in mind when I read the article again.
Do you have any photos of when your Green Gables bloomed?

I saw Peters comment re: Jovis and Semps?

http://garden.org/plants/brows...

it's ok that ATP makes the difference between Sempervivum and Jovibarba;

in newer botanical dictionaries this two species were put together under the roof of Sempervivum;

but that isn't undisputed and a lot of older collecters stay at the old version;

on our homepage we use the botanical names of the newer version (f.e. Sempervivum heuffelii) but we add "/Jovi" to the names; that's helpfull because there are a lot of names identical between Jovis and Semps;

Oh, Thank you, Peter, that clarifies greatly!

Thanks, Peter. The example (in Janice's reference which I had missed before) makes it clear what I was trying to get at.

Sorry, no photos of Green Gable here that I know of but I will keep that in mind. There might be some lurking, but unlikely. I lost a lot of early photos to a disk crash and now keep better backups of them.

I was looking at some of my older photos this morning, and came across this NOID (not Green Gables) again. Looking at the flower, it does resemble the flower of rosularia.

Here is my picture


Here is a picture on Fernwood Nursery's website http://www.fernwood-nursery.co... (scroll down toward bottom of page)

Hi Chris;

it's looking like a rosularia-flower - that's no sempervivum-flower;
they would have more and smaler petals...

Peter