South American Hardiness

[jam]

I would thing the northeastern populations of Escobaria missouriensis and vivipara would be even more ironclad for you. The ones from the eastern plains get plenty of moisture at times and their ranges into the Canadian Prairie Provinces for vivipara and east into Minnesota show they can take cold. I have had vivipara to 38 below zero in a seed tray and wet with no issues. Hoping to collect some seed of both from a ranch in eastern South Dakota next year.

On top of Escobaria I would add Pediocactus, there are various simpsonii variants which can handle our winters without rain shelter. With these I always try to look out for plants of Colorado origin. I also read some Sclerocactus can live through harsh conditions but haven't tried any of those, yet. If you're willing to provide rain protection in winter, the list of species would inflate drastically.

Yes, I always use rain cover. My Winter hardy cactus are grown in a 2' deep raised bed, with a hoop house cover in Winter. Did try a Pediocactus, but it did not survive.

I am sorry. I've always thought the south shores of the Great Lakes got moderated temperatures due to the water mass. I've checked Toledo, OH average temperatures and precipitation and you get colder from November to May and more rain per annum than my location. Thus what works for me may not work for you.

[jnewmark]

On top of Escobaria I would add Pediocactus, there are various simpsonii variants which can handle our winters without rain shelter. With these I always try to look out for plants of Colorado origin. I also read some Sclerocactus can live through harsh conditions but haven't tried any of those, yet. If you're willing to provide rain protection in winter, the list of species would inflate drastically.

Yes, I always use rain cover. My Winter hardy cactus are grown in a 2' deep raised bed, with a hoop house cover in Winter. Did try a Pediocactus, but it did not survive.

I am sorry. I've always thought the south shores of the Great Lakes got moderated temperatures due to the water mass. I've checked Toledo, OH average temperatures and precipitation and you get colder from November to May and more rain per annum than my location. Thus what works for me may not work for you.

Yes, we do get what is called, "Lake Effect " weather episodes here on the NW shores of Lake Erie. Actually, when I first starting growing Winter hardy cacti, about 25 years ago, we were classified as Zone 5A. Gradually it got warmer to now where we are in Zone 6A. But, we still get alot of moisture here in Winter, where it rains almost as much as it snows, and sometimes a mixture of both. It is not a "dry" cold here at all, with constant freeze/thaw conditions which usually means rot for many cacti and Agave that I have tried regardless of how much I try to protect them. Right now, my raised bed is mostly Echinocereus, Agave Gracilipes, and a small Yucca Nana.

[MJP]

At my old garden, I grew from seed and tried a great number of cactus species from Uruguay and Argentina.
All my hopes with *Gymnocalycium* species were eventually quelled - except for Gymnocalycium andreae which endured 5F. A few seedlings had gorgeous sulphur yellow flowers.

I also tried a great number of Notocactus species and seed selections.
The best performers were always Notocatus submammulosus from Cordoba Province, Argentina.
From Mesa Garden, seed collection djf276 was a standout. Older plants rebloomed in autumn - and set seed.

A few individual Notocactus turicekianus also survived 5F. Most, however, turned to mush.

I hybridized the survivors with Notocactus roeoluteus and Notocactus herteri to obtain seedlings with flower colors inclusive of orange and red hues.

The Notocactus sumbammulosus x herteri have surpassed my expectations for cold hardiness. They survived 11F without a problem. 2nd generation seedlings are now available at Plant Delights Nursery. Yes, I bought one for my new garden. [We moved 2 years ago].

---------------------
Gymnocalycium species I tried and that failed at or below 10F
- baldianum (not ever really a candidate with promise against deep cold, but with gorgeous flowers)
- bruchii (several clones tried)
- gibbosum (many seed collections tried)
- chubutense (rather promisingly from Chubut Province, Argentina - once again, however, a failure in the end)
--------------------
I also tried micro-opuntia species from Argentina, without success.

[Gafoto]

At my old garden, I grew from seed and tried a great number of cactus species from Uruguay and Argentina.
All my hopes with *Gymnocalycium* species were eventually quelled - except for Gymnocalycium andreae which endured 5F. A few seedlings had gorgeous sulphur yellow flowers.

I also tried a great number of Notocactus species and seed selections.
The best performers were always Notocatus submammulosus from Cordoba Province, Argentina.
From Mesa Garden, seed collection djf276 was a standout. Older plants rebloomed in autumn - and set seed.

A few individual Notocactus turicekianus also survived 5F. Most, however, turned to mush.

I hybridized the survivors with Notocactus roeoluteus and Notocactus herteri to obtain seedlings with flower colors inclusive of orange and red hues.

The Notocactus sumbammulosus x herteri have surpassed my expectations for cold hardiness. They survived 11F without a problem. 2nd generation seedlings are now available at Plant Delights Nursery. Yes, I bought one for my new garden. [We moved 2 years ago].

---------------------
Gymnocalycium species I tried and that failed at or below 10F
- baldianum (not ever really a candidate with promise against deep cold, but with gorgeous flowers)
- bruchii (several clones tried)
- gibbosum (many seed collections tried)
- chubutense (rather promisingly from Chubut Province, Argentina - once again, however, a failure in the end)
--------------------
I also tried micro-opuntia species from Argentina, without success.

Always helpful info. What do you suspect was the cause of death? Cold or moisture (or the insidious combination of the two)?

In my limited experience with cactus a lot of them don’t mind the winter moisture we get down into the 20s but once things get into the teens and lower is when damage occurs and major spotting happens. I think we generally don’t get enough moisture for exclusively fungal issues to be the cause of death with succulents.

[MJP]

The ability of a cactus (or any plant) to endure freezing, without cell death as result, depends on the kind and quantity of solutes in their cells.
These equate to antifreeze.

The colder the temperature, the better the antifreeze must be.

When the antifreeze fails, ice crystals form, and the tissue is ruined.

It is my experience from growing South American globular cacti, that the cold-hardiest small globular cactus is Gymnocalycium andreae (to about 5 F), and that the cold hardiest large globular to columnar cactus is Soehrensia formosa (10 F or slightly less). These are cacti of low heat environments, so unlike the desert southwest of the USA, and slightly more the like USDA Zone 7b in the Southeast USA, which is why they are successful here.

Neither of these species (or genera for that matter) showed any problems from wet soil due to rainfall (given well-drained soil and landscape position).

The problem for large globular and columnar cacti here is termites. They will sometimes devour the cactus roots, (this was limited to Trichocereus species for some reason) and via this route access the inside of the cactus. Fungal infection follows. If discovered in time a top cutting would save the cactus.

Thus are the vagaries of life for cacti.

[Meangreen94z]

I guess it depends whether you are willing to sacrifice and perform a true test or give in and provide some protection . A local friend has had 2 Trichocereus terscheckii for 20 years, first in Dallas and now relocated here. He wraps them in a canvas tarp and then a plastic tarp below 15°F. No heat applied but they have survived singled digits and 120 hours below freezing in 2021.

[jnewmark]

The ability of a cactus (or any plant) to endure freezing, without cell death as result, depends on the kind and quantity of solutes in their cells.
These equate to antifreeze.

The colder the temperature, the better the antifreeze must be.

When the antifreeze fails, ice crystals form, and the tissue is ruined.

It is my experience from growing South American globular cacti, that the cold-hardiest small globular cactus is Gymnocalycium andreae (to about 5 F), and that the cold hardiest large globular to columnar cactus is Soehrensia formosa (10 F or slightly less). These are cacti of low heat environments, so unlike the desert southwest of the USA, and slightly more the like USDA Zone 7b in the Southeast USA, which is why they are successful here.

Neither of these species (or genera for that matter) showed any problems from wet soil due to rainfall (given well-drained soil and landscape position).

The problem for large globular and columnar cacti here is termites. They will sometimes devour the cactus roots, (this was limited to Trichocereus species for some reason) and via this route access the inside of the cactus. Fungal infection follows. If discovered in time a top cutting would save the cactus.

Thus are the vagaries of life for cacti.

Would love to try an Andreae but can't seem to find one for sale anywhere in USA. EDIT: Found one at Planet Desert. Maybe I'll give it a try.