Mark (starch)--I'm glad to hear it survived the Phoenix inferno! As mild as your winters are, it should push new growth almost continually and become well established by the time the heat returns. I'll be very interested to hear how it does next summer with roots in the ground. It would probably be wise to shade it during the next hot season. Pardon my poor memory, but did you get it as an already-grafted plant, or a scion that you grafted yourself? What rootstock is it on?
I had been confused about reports that Brazos Belle is a genetic clone of Wilma, so I phoned Bill Schneider (who holds the trademark on 'Wilma') about ten days ago to see what he could tell me. He had no information about Brazos Belle, and could not tell me anything about its origins or relationship, if any, to Wilma. However, I learned that Schneider's trademark protects the specific product that he sells, and that he is the only one authorized to sell it under the Wilma name. As I understand it now, Wilma avocados are only those which he produces, which are on a particular rootstock and grafted in a specific way (with the graft union very close to the roots themselves), which allows the union to be buried a couple of inches or so below ground level. This way, the superior cold-hardiness of the above-ground portion is not compromised by exposure of a frost-tender trunk. His rootstock also has other advantages, such as tolerance of alkaline soil.
Schneider's reason for trademarking the Wilma name (along with others that he sells) is that if someone else were to graft scions from his trees in the more traditional way, say several inches higher on the rootstock, or onto less cold-hardy or otherwise inferior rootstocks, and sell them under his trademarked names, they could not be expected to perform as well as his trees, and might well damage the reputation of his particular product.
I was worried that I might have impinged on his trademark by sharing grafted plants and cuttings from my Wilma tree (which was purchased at his nursery), but he said anyone can propagate it any way they see fit, and even sell it, but they can't call it Wilma--they have to come up with their own name. So, if I understand it correctly, a trademarked plant is less restrictive than a patented plant (such as Peterson Pawpaw cultivars, which are illegal for anyone but Peterson or his authorized agents to propagate), but only the owner of the trademarked name can legally apply that name to plants propagated from the named variety.