I have a covered garden - 16ft x 9ft x 9ft in height - where I have been experimenting with "tropical plants". The inside temperature will get rather hot during the day (over 30C is not uncommon during the summer) but, being open at both ends, it cools off at night so below 0C is possible during the winter. And because it is covered it keeps things dry and frost free unless watered - plants at the perimeter can get moisture from outside but those in the middle can dry out if not careful. This has also allowed me to plant some cold hardy cacti and agave without them turning to mush during the winter months. Now everyone takes it for granted that cacti like the heat but I also know that a lot of deserts will drop to near freezing at night so cold temperatures don't bother them. I would like to experiment with planting so called "tropical cacti" in this area of my garden and was wondering if anyone else has tried something similar? Does anyone have any suggestions as to the type of cacti I should try, or do I just buy one from Walmart and give it a try? (but not the grafted type) Thanks for any and all input
What do you mean by "tropical cacti"? Melocactus? (Will not work.) Epiphytic cacti? (Some may tolerate it, but not all) Or something else? And what kind of cold hardy cacti have you tried already?
Tropical as in what is sold in garden centers and nurseries as 'houseplants'. I'm looking for the names of cacti that can handle cold but not the moisture because I believe keeping them dry but not necessarily warm during the winter months is the key and my covered garden is allowing me to do this. "Many cactus species can tolerate cold temperatures, although some can't tolerate winter moisture. The lowest temperature a cactus can survive, depends on the species". It's really hard to find even the cold hardy varieties and if you do they are all the same (as my list shows). So far I have: Agave Americana ‘variegata’ (now about 4 ft tall) Opuntia polyacantha, plains prickly pear Opuntia compressa, eastern prickly pear Opuntia compressa var. humifusa Opuntia erinacea ‘esquisite’, mojave prickly pear I acquired the opuntia last year as pads and they not only grew well but some even flowered, and they all handled the winter without issue. As for the agave, it's been in-ground in the garden for 3 years now and not only is it doing well but it's even producing offsets
The Opuntia on your list are among the toughest cacti you can find, except that O. fragilis is not there. The difference between them and "normal" cacti is quite big. There are some other cacti from North America that you can try, like Escobaria missouriensis + vivipara, and a few Echinocereus, notably triglochidiatus but perphaps reichenbachii and rigidissimus could work as well. It depends very much on the climate, air humidity seems to be important too, not just how wet the soil is. Among the more typical "houseplants", a few Rebutia could be worth a try, but don't expect too much. If you can find them, Gymnocalycium bruchii, gibbosum, and oenanthemum are good candidates, but I have only heard about bruchii being sold in garden centers. Avoid columnar cacti, they are rarely frost-tolerant. There are some more, but I have never heard about them being sold in garden centers etc.
Thanks for the info. I've been trying to get a hold of O. fragilis but it is native to certain areas of the province and therefore not often available....short of digging it up from the wild.
Sad, there are some very nice fragilis cultivars with large, beautiful flowers that should look great in a garden.
Strange how what we deem common or uninteresting because it's native is unavailable to us but usually ends up being sold in other countries as 'exotic' plants......