I have heard that many of the Citrus sold in Miami are on rootstocks not well adapted to our rocky, alkaline soil. I think this true because some of my Citrus are much more needy than others. My Satsuma and Persian lime require half the fertilization that my Meyer Lemon requires. I want to keep expanding my Citrus collection by grafting new varieties on my own rootstock.

So what is the best rootstock for alkaline rocky soil? Or should I just wander Everglades National Park until I find a healthy wild tree.

Sour orange will be your best citrus root stock for alkaline soil.
Take Care,
BC

A couple of problems I see. Sour Orange is, indeed, alkalinity tolerant. However, it will very quickly succumb to citrus tristeza virus in south Florida. I think I'd try one of the mandarin types.

However, be aware that budding your own citrus in Florida is against both Federal and State law, and they can and will come onto your property and they will notice a change in the number of trees you have. Then they destroy your trees and you can be fined.

I don't think that second part is true. How would they know I added citrus? How would they know I didn't buy them from a nursery? Its not like I keep my tags on the trees I buy after I plant them.

Besides the citrus police don't come around Miami anymore. Not after Costa farms sued and won millions of in compensation for having there groves cut down.

It is definitely true that propagation by anyone, by any means, in any number, for any purpose, is forbidden under state and federal law, except for certified citrus nurseries with all the psyllid-proofing equipment. Perhaps they're not patrolling your neighborhood; they are elsewhere.