I have this little aeonium on a warm South facing window. It grew a new rosette when I got it early in the year but hasn't done much since. I think I read somewhere that they go dormant when it's hot? Anyway, I have this odd looking stem poking through the soil now...you can see it in the second pic. Does this look atypical or is it just what they do?

Yes, they rest during summer (to greater or lesser degrees depending on the plant and the conditions). It looks like the plant branched below ground level (maybe there was a lot of buried stem) and the resulting shoot lost its chlorophyll due to lack of light, but has now broken ground level and will proceed to regain that color and turn into a regular branch.

I've never seen that before, but this is my best guess.

If it were given stronger outdoor light that somewhat buried stem can try to make new rosettes anywhere along that stem as it attempts to grow upright.

If it were mine, I would move the container outdoors. But if your area is rainy, just be careful as you keep it indoors. It may eventually rot.

My aeoniums here stays outdoors and as our weather stays too hot and dry, they go dormant and ratty. It will be in late Fall before these ones perk up again.

Baja_Costero said:Yes, they rest during summer ......

@Baja_Costero , I always think that all succulents will grow in spring/summer and rest/dormant in winter, until I saw your post in other threads that mentioned lithops will rest in summer, and now this, would you mind to share which species of succulents will go dormant in winter and which one will rest in summer ? Tx

I believe it depends on where they grow in the wild (Northern or Southern hemisphere), as the Southern hemisphere is opposite of Northern with respects to winter and summer (and vice versa).

So you take a "Southern hemisphere" plant and grow it in the Northern hemisphere, it's care will be opposite (goes dormant in our summers, grows in our winters).

It also depends on the rain pattern where they evolved. The Canary islands are a 'Mediterranean' climate where it is warm/hot and dry in the summer and cool and moist in the winter. In other areas it may be warm and wet in the summer and cool and dry in the winter.

if thats the case, then what if I change the question, I want to know which species go dormant in hot weather and which ones go dormant in cold weather, then we will just focus on the weather/climate where the plant is growing now..

The hemisphere of origin does not change whether a plant will be active or inactive during summer. A plant does not have a "memory" of what half of the planet it came from... if you moved a plant from (say) South Africa to (say) California, it would be confused for a while (maybe the first couple months) and then resume its normal seasonal behavior, to the extent it had seasonal behavior to start with. Maybe it would skip a flowering season or flower off season its first year.

There was a list of summer growers and winter growers circulating on the internet a few years ago, and though it was mostly inaccurate, it was useful as a point of departure. Summer dormancy depends on the climate of origin, specifically its seasonal rainfall pattern, but cannot necessarily be predicted from that.

Aeoniums are (mostly) from the Canary Islands, which have a Mediterranean (winter rainfall) climate pattern, and they are winter growers. So is Senecio kleinia, a deciduous succulent shrub, which loses all its leaves in summer.

The winter growers around the planet come from Mediterranean (winter rainfall) climate patterns, which exist in about 5 different locations globally. Outside the Mediterranean itself, they tend to be on the west side of continents in the subtropics. They exist in Mexico (ie. Baja California) and the succulents from this area are either year round growers (no dormant season) like our native Agave shawii, or they are winter growers (summer dormant) like our native Dudleyas.

The greatest diversity of winter rainfall succulents comes from South Africa, which has summer rainfall and winter rainfall (and mixed) zones. The west coast of South Africa has winter rainfall, with increasing aridity as you go north. The more arid the climate of origin, the more likely the winter rainfall aspect will dominate a plant's growth in a more forgiving climate. Some examples of winter growers (summer dormant plants) from South Africa include Tylecodon, a whole genus of succulents that lose their leaves during summer; and Pachypodium namaquanum, the only member of its genus which goes deciduous during summer and experiences most of its active growth during winter. Both of these would be terrible ideas for climates with lots of summer rainfall. I know people who have tried and were disappointed.

The important distinction here is between hard wiring (so-called obligatory summer dormancy) and responses to environmental stress (eg. summer heat and drought). Not all plants from winter rainfall areas will be hard wired to go dormant during summer. They will usually be opportunistic in their growth pattern and keep going when conditions are favorable (as they generally are here, at least on the patio).

As for which plants go dormant in hot weather, that probably would apply to lots of plants which do not necessarily come from winter rainfall climates, but for whatever reason do not tolerate heat very well. (Maybe they come from high altitude.) I would not treat the groups as equivalent, though the end result may be the same in a hot climate.

A long answer and more than you wanted to know...

To illustrate: here's a shrubby Aeonium hybrid in the landscape in full summer mode. The rosettes are smaller (fewer leaves, shorter leaves) and closed up on themselves. There's nothing wrong with the plant, it just hasn't rained properly since March and it usually doesn't rain until October at the earliest. It will rebound and green up after that point.



If you look at the two red arrows I put in there, you can see "waists" in the stem where it narrows and the leaves are packed much more tightly together (judging by the scars they leave behind) along the stem. That is summer stem. The distance between the two arrows is one year's worth of stem growth.

Compare and contrast that image to this one (same hybrid, just growing on the patio) in mid fall.

Thanks Baja, it is clear now that I cannot just generally assume the dormant period for the whole species, tx