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This section is dedicated toward maintaining one active thread for each Crassulaceae species/subspecies/variety/cultivar. Please feel free to add information and/or photos to existing threads or start your own by adding Genus/species as the thread subject. Note that listings are displayed alphabetically. Enjoy!
It seems that a lot of the Simsii in cultivation are actually simsii based hybrids, and not pure simsii. From experience, the easiest way to tell if a plant is pure simsii is by looking at the water tubes at the back of the leaves.
Same in the UK, historically plants sold as simsii are the hybrid with spathulatum called x barbatum. Although, that said, I find x barbatum to be a better garden plant than either simsii or spathulatum, both of which are majorly summer dormant yet the hybrid not so much.
A. simsii is interesting to see in habitat - it grows only on the Canary Island of Gran Canaria, only at the highest altitudes there and almost invariably on the north/shady side of rocks or at the base of trees in the shade of their canopy.
I don't have anything wrong with the Hybrids, but it will impact the plant's cold hardiness. Simsii is rather frost tolerant, tolerant down to the low 20s f. However, most of it's hybrids (simsii x zwartkop, xSventenii, etc) are only hardy down to 25 degrees f.
I used to have this Simsii hybrid. It's one of the more common Simsii hybrids in cultivation here, but it is clear that it is NOT pure Simsii. A nice ground covering plant, anyway. From experience, purer simsii form longer stolons... Also, note that the marginal cilia on this plant are shorter, point upwards, and less than an mm in length. I'd be curious if the Barbatum hybrids have the idioblasts that are present on Aeonium Spathulatum.
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Aeonium Simsii Hybrid.
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Actually A. spathulatum is more frost tolerant than simsii. At least here. So the hybrid between these two parents is tough, my x barbatum was barely damaged at -8C with two weeks below freezing day/night one bad winter.
How do these idioblasts manifest themselves? I thought the term was some specialised cell or other but could be wrong - I'm on thin ice with botany. I remember I'll take some pics of my plants tomorrow.
@Paul S
From my understanding, the idioblasts are the water storage cells. They appear as black/brown spots, or the dots at the back of the leaves. They appear similarly to the water tubes on Simsii, just that they are dots.
Great photos! Amazing rock garden. It's too bad I can't get seeds from the UK. It appears that many of the species available in the UK aren't available in the US, and vice versa.
