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  Tucson Cactus and Succulent Society

Growing Succulents in the Desert Column

(List of Growing Succulents in the Desert columns)

Ferocactus of the Month
"Ferocactus latispinus and F. latispinus ssp. spiralis" by Chris Monrad

Photos by Chris Monrad

(This article may only be reprinted with the author's permission.)

Ferocactus latispinus and F. latispinus ssp. spiralis (formerly known as Ferocactus recurvus or sometimes as F. nobilis) are two more of the winter blooming ferocacti, with various specimens of F. latispinus typically blooming in local cultivation from late October through late January. Ferocactus latispinus ssp. spiralis generally blooms two to three weeks later than F. latispinus. F. latispinus is widely available in the trade and is well known for its vivid solid purple flower (Fig. 1) and displays a cream colored flower in the lesser-available and blond-spined variety. Ferocactus latispinus ssp. spiralis and its darker purple striped blossom (Fig. 2) is generally seen less frequently for sale but can be found locally at some TCSS member nurseries. I suspect that F. latispinus is better established due to its propensity to bloom at a smaller size and therefore being more aesthetic and marketable in this regard. The blooming periods can vary from specimen to specimen depending upon growing conditions, weather and perhaps just kismet.

If seed production is desired, hand pollination is recommended due to the sporadic to non-existent insect pollinator activities associated with the seasonally cold weather in Tucson. Unfortunately, local hard frosts may cause fruits to abort prematurely even if the initial pollination is successful. Native to Puebla, Oaxaca and surrounding tropical locales in Mexico over 1000 miles south of Tucson, these species are a long way from home and their naturally occurring pollinators. F. latispinus ssp. spiralis has a larger and more upright growing habit and twists as it grows (Fig. 3), hence its epithet. It also has a longer central spine and a simpler yet very sturdy spine cluster, in that it lacks the more delicate spider-like lateral spines of F. latispinus.

As with many cacti, various clones are more frost hardy than others. The recent cold snap of early January 2011 burned the ribs of one of my specimens of ssp. spiralis at an unprotected 22F (Fig. 4) , while several other specimens in my yard were unharmed and held their flower buds through the same 22F , also with no protection whatsoever (Fig 5). It is still possible that the buds will ultimately fail to open due to the frost but the plant itself is unharmed. These plants are suitable for full sun conditions in pots or in the ground, but do benefit from well draining soil and regular supplemental watering when stressed. Time-release granular fertilizer administered in May will carry the plant nicely through the monsoon season.

As seems to be the case with the dedicated cultivation of ferocacti in the suburban and rural Tucson area, our native Cactobrosis fernaldialis moth and its Blue Cactus Borer larvae (not to be confused with the invasive Cactoblastis moth that preys upon Opuntia species) can cause damage or sometimes death to small and occasionally even larger specimens if enough larvae infiltrate the plant. (Fig. 6) portrays the entry points in which several female moths have laid eggs within the tissue of a Ferocactus latispinus and (Fig. 7) shows the blue larvae and the damage to another plant resulting from its feeding and attendant rot. Non-native exotic ferocacti are definitely more susceptible than our native F. wislizenii, but the Cactobrosis moth will also target sick or stressed natives. If you live in Southern Arizona outside of the urban Tucson core, you are likely to see calloused-over circular infiltration points on ferocacti of many species if you look closely for them. The persistent and rigorous use of systemic insecticide is known to be effective in limiting the damage of the moth larvae but can be costly, time consuming and may have food-chain implications on the pollinator community. For this reason, one may be advised to just cultivate a few more plants to allow for the occasional loss. After all, the moths were here first.


List of Growing Succulents in the Desert columns