“Flowering Your Cacti” By Heather Farmer

“Flowering Your Cacti”

By Heather Farmer
Box 331, Cranbrook, B.C. V1C 4H8

Every time I think of the term “flowering“ my cacti, I have to stop and consider whether I should use it or not.  It sounds to me as if I am doing the flowering and does not give due credit to the plant.  I am sure that my plants are saying “if that stupid human would just give me what I need, I will do the flowering!”

In view of this conversation with my “wards”, I diligently try to give them everything they need.  I research and make notes on not only cacti in general, but each individual species, to see if there is something special they need.  I have found out certain facts such as Aporocactus  species like a little added bone meal and don’t push Mammillaria sheldonii  too early in the year as it likes to grow and flower later in the summer.

I water very carefully.  I inspect each of my over 150 plants to determine how much water they need.  I give them maximum water they can take in the summer.  This is sometimes risky as too much when they are not growing can cause them to rot.  I must make sure they are growing, which, with some of the slower species is not always easy to tell.  I cautiously harden them off in the fall and bring them back to life in the spring, trying to balance weather conditions with how much water to give them.  In the winter, I worry that some species don’t like to be completely dry and others need to be.  I panic when my watering can slips and I give one too much.  I then sit them under a warm lamp, hold my breath and keep my fingers crossed.  (It’s very hard to work in this situation!)

I watch and research each plant to determine the maximum light each should have.  I juggle them between windows and outdoor places in the summer to find a spot each likes.

I even watch how each one likes the kind of pot it is in.  Some have really done a lot better when I put them in a different pot.  It is a proven fact that some species will not bloom if they are in a too-large pot.  Epiphyllums, Christmas and Easter cactus and I suspect other hangy-downers (jungle cacti, epiphitic cacti) such as Aporocactus  need to be pot bound to produce flowers.

Many cacti will not flower in captivity as they cannot grow large enough or need unlimited root space that can only be achieved outdoors or when planted into the floor of a greenhouse.  Most opuntias are like this, and of course the monsters like Carnediea gigantica  or saguaro, and Cephalocereus senilis  or old man cactus.  Cleistocactus  and Trichocereus  do better with free root run.

All cacti need a rest stage in order to bloom well.  For most cacti this means a period of limited water and very cool temperatures.  My cacti get 4 months from 1st November to 1st March with minimum water and temperatures below 15 degrees Celsius.  Most probably experience temperatures lower than that as they are on windowsills.  These temperatures must be balanced with the amount of watering given the colder the temperature, the less water they can take.  Again, different plants need different temperatures.  For example, Coryphanthas  such as vivipara and some Mammillarias  such as longiflora  can take close to freezing.  However, some cacti such as Setiechinopsis, Hylocereus  and I am suspecting Gymnocalycium bruchii  and andrea  might develop ugly and possibly killing orange spots like a rust because they were kept at too-low temperatures.  Some plants are dormant at different times of the year.  The Christmas Cacti are dormant in March at my place in south-eastern B.C. while the main body of my plants are waking up.  Some epiphyllums  have been growing all winter.  They have short rests after blooming in the summer and some also rest in winter.

By now you may be saying, “Gracious, this is extremely complicated!  Forget flowering!”  But wait.  Can anyone tell me how my mother has managed to get a Cereus peruvianus only 30 cm tall to bloom?  Can anyone tell me how my girlfriend can get most of her varied types of cacti to bloom consistently?  She doesn’t have any species names committed to memory, much less studying their habits and behaviours.  She treats all of them the same, mostly to the point of neglect.  How can she do this and raise gorgeous plants?!

It is my suspicion that the person who told you you had to study and know your cacti and treat them very carefully just said and does so because she likes to play with her plants.  The keys to flowering are a cool, dry rest and good sun.  Period.


Source:  This article is from the very first issue of The Amateurs’ Digest, in May of 1989, when it went by the name Cacti & Other Succulents.  There is no ISSN showing on this little 8-page first issue.  Very possibly, an ISSN was attributed later.