Yes, you can grow Dioon spinulosum cycads in the Phoenix, Arizona area. I have three, and they have all been here over ten years. I think they're beautiful, as they look either like big ferns or small palm trees. I've never seen them for sale here in the Phoenix area, like at Home Depot or places like that, but they are common in Los Angeles, and are not expensive. That is, they're about the same as a sago palm (cycas revoluta).
There are a few tricks to getting Dioon spinulosums to be happy in the desert, though. As you can see in the photo, they like shade. They also like the frost protection provided by a tree. Like all cycads, they only grow once a year in spurts called "flushes", so they use very little water in the summer and none at all in the winter. No, they're not cactuses (cacti?), so you can't just put them in the ground and forget about them, they just about the only way to kill them, or any cycad, is overwatering. Plant them in well-draining soil on a slight slope where the water can drain away quickly. Cycads don't like standing with "their feet wet"!
I call this area the Dioon garden, but I have Dioons all over my property. The fine-leaf one in the foreground is not a spinulosum, it's an edule, but the two bigger ones in the deepest shade, are "spinners" (as we cycad collectors like to call them).
Like all cycads, spinulosums grow very slowly. They can get very tall, over forty feet, but the only ones I've ever seen like that are the ones in Pacific Palisades, which are about 100 years old. In a normal lifetime, they really won't get very tall. By the way, I've made planted mine where they would have room to get very tall, in case the person who is in this house after I've gone wants to keep them.
By the way, "spinulousum" means spiny, so plant them away from where people walk. The leaves are stiff, and sharp!
|Dioon spinulosum flushing|