Heat tolerant succulents ?????

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don
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Location: Carefree, Arizona zone 9b

Heat tolerant succulents ?????

Post by don »

I have lots of cacti but recently I've been attracted to succulents. I particularly like sempervivums, echeveria, and some sedums. My concern is tolerance for heat in zone 9 in the foot hills 40 miles outside Phoenix (average summer temps 102-107). My reading tells me that the occasional dips into the upper 20's in the winter here in southern Arizona is not the problem but I don't know about the heat. Is it best to put them in containers in the partial shade or can they go into the ground (sun or partial shade?). If these are not good, what succulents would be best?

thank you
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Harriet
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Post by Harriet »

I will be interested in the responses you get to this question. I wish there was a heat tolerence index for plants as well as cold tolerence information. Learning through trial and error can get expensive, and I don't like to murder plants.

I have found that many (but not all) of the semperviums and sedum do not like heat and humidity and can just melt away. You might have better luck if you have cooler nights than I do, and can keep them out of the full sun. Good luck!
It’s not the fall that kills you; it’s the sudden stop at the end.
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Peterthecactusguy
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Post by Peterthecactusguy »

I too sorta wish there was a heat tolerance for plants. The desert is a harsh environment. I also have a lil trouble believing that Carefree only gets to the temps. I think they might be a little warmer. I know the inside of my car got to 186F in Cave Creek. (don't know what the outside temp was) also my high temp in the shade in Black Canyon City is 117.9 degrees.

Just saying, I would be careful what you plant. A lot of the succulents other then Cacti that I like would get fried :(
Here's to you, all you insidious creatures of green..er I mean cacti.
don
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Heat !

Post by don »

thank you Harriet and Peter. Yeah the temps I mentioned are average...it exceeds 110 several times during the summer and the nights hover around 80 but at least it's not humid like Florida. I have one pot of echeverias that I just planted from cuttings and they seem to be OK but I have them in partial shade...still too soon to tell for sure.
Buck Hemenway
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Post by Buck Hemenway »

I feel for Harriet. Her weather is just not desert-like. The night time conditions are the real difference. It always cools off in the dessert and, of course the humidity difference is huge.

You need to pay attention to where your plants come from Don. In particular, sempervivums generally come from the mountains of Southern Europe. Hard to imagine a lnat that is native to 6000 ft elevation in Spain or France liking Phoenix weather.

You should take an afternoon to look around the Desert Botanical Gardens in Phoenix. They've done a really nice job of displaying plants that can survive in your garden. Pay attention to the ones in the shade houses or that have been planted under trees. You'll need to provide the same protection at your house. Lots of succulents will do well, and some will really surprise you. A number of aloes will do well there for example.

Our weather is not quite as hot as yours, but we have a number of 110 plus days every summer. We plant what we like and most survive, some thrive and others just don't like the super heat.

One great source of information is the local C&S club. Central AZ C&SS. They meet monthly and almost everyone there will have experience, just like you're getting with the echeverias. Not all, but some of those come from areas in Mexico with weather exactly like yours.
Last edited by Buck Hemenway on Tue May 18, 2010 4:19 pm, edited 1 time in total.
Buck Hemenway
don
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Heat !

Post by don »

Thank you Buck. The natural habitat of sempervivums is exactly what prompted my question. I'm glad to hear that you've had good experiences in Riverside with many succulents...I'll be careful with the direct sun and see what happens. (I'll wave as I drive through Riverside Friday on my way to see my mom in Carlsbad)
iann
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Post by iann »

The Echeverias may come from Mexico, but generally quite high in the mountains. It is unusual to find them with the cacti, they like it cooler. They are found right the way down to South America though, so possibly some of them like it hot.
--ian
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Peterthecactusguy
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Post by Peterthecactusguy »

I too am starting to take an interest in succulents. I need to get a few. I want to try growing those pickle plants in the shade. I have a pretty nice spot that is always shady that they would look good in. I also need to find some more succulents for the desert. Most of the ones I like won't grow here in the ground tho!
Here's to you, all you insidious creatures of green..er I mean cacti.
don
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Post by don »

I "borrowed" some Echeveria cuttings from my friend in San Francisco and put them in a pot about 8 weeks ago. They are actually blooming but they don't look like they are real happy. More shade might help and I'll see if they make it.
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Harriet
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Post by Harriet »

I wonder if in your situation, putting them in the shade and watering more might do the trick. If it is too hot during the day would the extra water cool them down, or just drown them?
It’s not the fall that kills you; it’s the sudden stop at the end.
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Peterthecactusguy
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Post by Peterthecactusguy »

Harriet,
I sorta wonder myself about watering cooling down plants. I think it might because when water evaporates it cools off the air around it, if that makes any sense. Arizona is pretty dry this time of the year and I am thinking that if the water evaporates outta the ground around the plant it might cool the plant.

PeterB mentioned steaming the roots tho, so I am not sure, because the soil can get very warm to the touch.
:dontknow:
Here's to you, all you insidious creatures of green..er I mean cacti.
Buck Hemenway
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Post by Buck Hemenway »

The other thing to be careful of is that many succulents will enter a dormant state when the weather is too hot for them. Certain death if you over water during that period. Shade will help in Arizona, at least it will keep them alive until the weather cools and they can start growing again. You have one of the finest sussculent display gardens in the world in Phoenix. Go there and see how they handle the succs.
Buck Hemenway
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Peterthecactusguy
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Post by Peterthecactusguy »

Buck,
I assume you mean DBG. It does have a really cool display of succulents and cacti. :)
I need to go back again someday when I am not rushed! :)
(also so I can buy more cacti hahaha)
Here's to you, all you insidious creatures of green..er I mean cacti.
JEPlants
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Re: Heat tolerant succulents ?????

Post by JEPlants »

Every Phoenix nursery I've asked has recommended shade past about 9, maybe 10 a.m. for cacti and succulents in the summer here--with shade cloth if need be.

More frequent watering IN the sun doesn't help most (unless a plant that can definitely handle summer desert sun--e.g., some agaves and some cacti). Just shade them, I was told.

My own experience is that thick-leaved plants are likelier to survive the heat because they retain water better. Sedum adolphii and graptosedum California sunset, for example, plus gasterias, some haworthias, and some aloes. I almost always kill sempervivums in my indoor-growing environment; so, I strongly doubt they'd survive high temps and low humidity.

Mature plants (with good roots) in the ground need to be watered less often presumably because roots can go deeper and because the ground will be cooler than a pot sitting on concrete, but completely dry soil (top to bottom) in the heat seems to be a recipe for disaster. Wet at watering time then left to mostly dry out (root area lightly damp) before watering again is what I aim for. Lightly damp will be cooler than bone dry.

Water-absorbing gels (like found in diapers) near the roots can help hold water and keep the root ball cooler. My plants like the gel I use which is the potassium form instead of the sodium one (if I recall that detail correctly).

Jennifer Everett
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