mcvansoest said:I doubt that soil matters too much as it grows naturally in pretty much crappy soil to begin with. Given your climate you will want it to be fast draining, but I am sure you figured that out.right now it's in your average catus potting soil. The pot is deep. Was thinking of repotting it soon. Think I'll add something so it drains better. 3 year's ago I grew a lot from seed just because I thought it would be fun. Most germinated but That's the only one that made it past it's infant seedling stage. so I really want to take good care of that one. Thanks for the tips.
Thing is Wisconsin vs. the Mojave Desert is a difficult comparison when it comes to providing a comparable growing environment - you will want to give it as much sun as possible, ideally day long (of course be careful when you move your plant into more sun especially if you are moving from inside to outside) full exposure. Pretty much nothing else tall grows around these plants in their habitat so they get little to no shade. Rain is episodic but in a pot you will want to find a schedule where you give the plant a good soak and then let it pretty much dry out before watering again.
They grow reasonably successful here in the Valley of the Sun (Phoenix Area) which gets hotter than the Mojave but is not too different water wise. They are considered reasonably fast for a desert plants at about 3" year in their early lives, slowing down later, but in their natural habitat their growing season is just way longer than what you can provide.
I suspect but am not sure that to even begin to thrive it will need a bigger pot, this is not a yucca that is supposed to stay small and it is used to harvesting water from a large area, so I suspect it wants to make an extensive root network. It also has a deep root system so probably has some roots that serve as tap/water storage roots, so a shallow wide pot is not going to it.
I guess my final comment would be that there are other yuccas that remain smaller throughout their life that might be better suited to pot culture, than the Joshua tree, for which even 'small' specimens still top out at 2.5m tall.