Growing Ariocarpus and Astrophytum Species Outdoors

[hegar]

I hope, that I can find a few members of this forum, who do grow Ariocarpus and Astrophytum spp. cacti in the ground of their yards.
I have been trying - most of the time with limited success - to grow members of these two genera. Some of the plants did last for several years, but then died of root rot.
The people, who do have what seems to be successful growing experiences, are cactus lovers, who grow their plants indoors, where it is much easier to control the conditions they are exposed to.
Is there anybody else on the CactiGuide forum, who has plants of these two genera all year round established in whatever kind of growing medium in the ground?
If so, and if you do have success growing these outdoors, would you please respond to my plea and let me know, what you are doing in order to keep these plants alive?
I do lose almost all of my plants in early to late spring. Perhaps my soil is too moist during the cold part of the year. We do have regularly subfreezing temperatures here in El Paso. Most of the time the temperature does not drop below 20 degrees F, but we have had a few single digit temperatures for a few hours in January/February as well.
I am trying to plant these two genera in very coarse growing medium, consisting of coarse sandy material collected in the desert, topped by golden granite pebbles. Would it help, if I were to just stick the cacti in a thick layer of the pebbles, so the roots would not even touch any soil/desert sand at the time of planting?

Harald

[cactushobbyman]

I've grown Astrophytum ornatum outside in my garden for several years. I have mine in full sun and with this heat wave they are showing a little stress. They have flowered, set seed and I have seedlings a few weeks old from them. My temps in the summer, 110 degrees and in the winter mid 20's. Last year we had 14 inches of rain and they did well. I have a few in pots outside and they get some shade during the heat of the day and they are looking better than in the garden. Ariocarpus; I have a spot in the garden that I'm going put some, but as of yet, I have other projects to do. I'm going to put other cactus with them, and I think they will be okay even though others say they will not make it. My soil is heavy clay and now when I plant I will add amendments to the soil for extra drainage. I have other Astrophytum in the greenhouse and they seem to die more than the ones I have outside. I do water the outside cactus about every two weeks during the growing season.

[hegar]

Hello cactushobbyman,
thank you for your quick reply. Of all the Astrophytum spp. I only have one larger A. capricorne, one A. capricorne ssp. senile and - lo and behold - two A. asterias hybrids left alive. I am myself surprised about the A. asterias hybrids, which have been in the ground ever since they were seedling plants. They are flowering several times a year and have grown quite a bit bigger, than what you could expect a pure-bred A. asterias to do.
Perhaps there is some truth about what my former horticulture professor called "hybrid vigor". I hope, that the three older plants will be with me for a good number of more years.
The general consensus is, that A. asterias tends to develop root rot more easily than members of the other species within that genus. A grower, with what looks like perfect plants of both Astrophytum and Ariocarpus spp. told me, that he does cut off the tap root of young A. asterias seedlings, which results in a more fibrous root system and less root rot. I shall try that method, when I purchase my next small A. asterias.

Your climate is equally extreme to the one I do experience in El Paso. However, because of our altitude (4,000 ft above sea level), we do have slightly colder winters and cooler summers. Most of our rainfall occurs during the summer months (June - August) and we only receive about 8 inches of precipitation per year. There is a possibility of snow during the winter and except in very rare instances, the difference between the low night temperature and the high day time temperature is considerable during the winter months. At night it might be around 20 degrees F, while during the day the temperature will be about 70 degrees. I thought, that perhaps the snow that does accumulate on the ground and can be over 1 inch thick, followed by the usually rapid melting during the day could contribute to the Ariocarpus spp. plants death by root rot.
Also, I have noticed, that members of that genus do not like to be exposed all day long to our strong sunlight. So I am planting these cacti in filtered light underneath a tree so that they get some shade during the hottest part of the day.

Harald

[kuni1234567]

I grow all of my cactus outside in pots and some are in the ground. I live in Los Angeles near the ocean and believe that some cactus do not like winter rain, but I still grow my cactus outside. The minimum winter temperature is around 45F and think that your winter temperature is too low for those two genus. I would use a cold frame with double plastic layers to increase minimum temperatures or put the plants into pots that can be taken out of the cold. I live within fifty miles where cactus plants grow naturally, but there are no Ariocarpus or Astrophytum that grow in California.

[hegar]

Hello kuni1234567,
I have been in contact with a blog member, who is very successfully growing all kinds of Ariocarpus spp. and also Astrophytum spp., which I also do love. He does grow these plants in a greenhouse setting and is thus able to regulate everything from watering to fertilization to temperature.
By what he has been telling me, it seems like the cold, and oftentimes wet soil during he winter months is the reason for me losing these plants as often as I do.
Ariocarpus fissuratus ssp. fissuratus does grow in the wild in the Big Bend area of Texas. That is not too far away from where I live. The plants that do reasonably well and have survived a number of years in the ground are Ariocarpus retusus ssp. trigonus, and Ariocarpus fissuratus ssp. fissuratus.
I did have two plants - one an Ariocarpus bravoanus, and the other an Ariocarpus retusus x agavoides hybrid - flower this year. However, before I will state, that they are good for outdoor growing here, I will need to keep them alive another two or three years.
I did plant three large A. fissuratus ssp. fissuratus plants in a big planter and will place that in a location that does not receive rain during the winter. If everything works out as planned, these plants should be doing fine when the next spring arrives. The others I may cover with a tarpaulin, in order to reduce an accumulation of moisture. That would also protect them a bit from low temperatures.
I shall be reporting about the results late next spring and hope, that only very few, if any, will be dead by then.

Harald

[hegar]

Here it is, almost May and I can report, that one of my two Ariocarpus bravoanus plants - the larger one, which flowered last fall - succumbed to root rot. The other one may still be alive. The three potted large A. fissuratus plants are doing well. Hopefully, I will be having nice blossoms on them this fall. All the other plants are doing fine, but I doubt, that any of them will be blooming.
I did go ahead and planted the newly acquired Ariocarpus and Turbinicarpus spp. plants in a growing medium made up of about 50% of my native sandy loam and 50% of grit-like material, which I hauled in from the Orogrande, NM arroyos.
Cacti, that are placed just in this small gravel mix after having been obtained from the mother plants, are doing really well. Despite getting watered three times a week, they do not develop root rot. The growing medium does drain rather well though, which probably is the reason for this success.

Harald