Green7humbs said:I've been desperately in search to figure out what the genetics are so I can treat this plant how it wants to be treated and really let it grow. I'm just shocked to find out that the plant needs full sun and is also in the hardy category. I've certainly not been treating it like it wants so it's time for a change.
For what it's worth, F. purpusii is a highland plant. It's found above 5000 feet in tropical Mexico. Intense summer sun there is not accompanied by heat the way it is in St. Louis at 500 feet. And I don't know if the plant needs full sun. I would say it does not. Most sun-loving plants do better in part sun (like 4-6h/day of direct sun) or filtered light (25-50% shade) when given the choice. I can say this from direct personal experience with a fair variety of sun-loving succulents, though not the species in question. And the database here indicates tolerance more than needs, when it comes to exposure, and those err on the side of what's possible in a permissive (mild) climate.
"Full sun" is defined as more than half a day (>6h/day) of direct outdoor sun. It is impossible to provide full sun indoors, because regular window glass filters out a lot of the UV part of the spectrum (which you can't see with the naked eye). Indoor sun is not direct, though you might not know by looking.
I would think natural light would be the best choice, if you can provide a very sunny southern exposure during winter. Like right in front of a southerly facing window. Be careful about introducing your plant to outdoor sun.... do it gradually, in steps, from bright shade to morning sun or filtered sun and so forth, over the course of weeks. The UV in direct (outdoor) sun can be punishing for plants that have not had time to adjust. And as Daisy said, try to change one thing at a time for best results.
Fouquierias have a season of active growth, which roughly follows the calendar (F. columnaris: winter) or depends on precipitation (F. splendens: various) or some combination of the two. This is when new stems are elongated and you see the type of leaf with long petioles. At this time they enjoy regular water when the soil is going dry at depth, and do not particularly enjoy sitting with dry soil for any extended period.
They also have a season of rest when they go somewhat or totally leafless, depending on genetics and conditions, and that's when they will only have short-petiole leaves, the kind that sprout from the base of the spines. During the season of rest you probably want to make sure the soil is going dry in between watering most of the time. If it occurs during winter, be aware that low light and low temps will tend to slow down the process of evaporation, which is the main route water will leave the container when the plant is not actively drinking. So do not overwater during the rest period, especially if it occurs during winter. Do not withhold water, either. I would think it's probably a good idea to keep temps above 45°F during winter if reasonably possible, despite the rated minimum of mature landscape plants.
Here in our mild climate I water my Fouquierias the same year round, but our climate is very mild (average high and low temps in December were 65°/53°F) and I definitely would not recommend that treatment elsewhere, especially if the plant endures a dramatic period of dormancy. F. purpusii will grow for most of the year if temps are moderately warm. It probably would be best to use a mix of 50% organic, 50% rock (or more rock if you're into watering a lot), which is what I use for my other F's.
Choice F. purpusii here from a grower's page (already sold) so you can see what proper care can give you.
http://raresucculents.com/extr...
