Anwers the question: Is Mexicola a good rootstock for Florida ?

[CTMIAMI]

A picture is worth a 1000 words.

[JakeFruit]

Unless that's some new variegated variety, I'm guessing that's a "no" to the question.

Related question, what variety(s) of rootstock are good in Florida that a home grower can obtain fairly easily? The stores around me only carry the "slim-cados." I end up planting any and every non-Hass seed I can get my hands on. Seeing your pic gets me worried some of the seedlings I'm using as rootstock are going to leave me sad in a few years.

[CTMIAMI]

Jake, Slimcados is just a trade name for Brooks Tropicals. Encompasses all the fruit they sell.
If  low temperatures is not your concern, the safest bet, short of having access to Waldin avocado fruit is to make sure you can ID West indies varieties. 
Public, and Winn-Dixie will carry the fruit. Out of these the best will be Waldin but you also have Simonds which will be in the stores the first week of July and is a very decent root stock. My Zutanos are on Simonds and are spectacular.
Waldins,  if they hit the store (because of the high demand for seeds) will be in mid August,  but they do make it to the stores, the premium ones will make to the stores, the rest will be used for seeds.
Do not use Donis, avoid Lulas due to susceptibility to Laurel Wilt.

The other solution will be to get together with a group in your area and come to Homestead and get a couple of boxes of Waldins. By the way the seed market is going crazy, Waldins are used as nurse seeds in the cloning process.



 

[JakeFruit]

You've given me a good plan, thanks Carlos. I'll start staking-out my local Publix in July/August. 
Are there any commuter/regional airports close to your place? I have a buddy with a single prop plane, flying would shave half a day off the trip.

Since you know most/all avocados, can you identify this seedling? Fruit was small, Hass-sized but had a pear/teardrop shape; skin was dark green when they were ripe. Seeds were tiny, walnut/pecan-sized, seed skin clung to the flesh, hard to separate. Flesh was creamy, made pretty good guacamole. Guessing it's some Mexican variety. The seedlings are healthy, but even the biggest trunk is maybe pencil-width. I have a few skinny scions grafted onto some of them, they look like they might take. Now I'm worried the seedlings I grafted to are Mexicolas :/

[CTMIAMI]

Was the origin of fruit store or private?  Very hard to tell from a seedling what it is. I do know some Mexicans take a long time to size up. Did you try to rub/crush the leave to see if you get an anise smell? 

Closes to Avocado producing area are the Tamiami Airport and a smaller Miami Homestead General Aviation.

[JakeFruit]

Private; I did not get to see the tree, my lawn guy brought me a box of various avocados from his other customers who didn't want them or were snow birds. I'll probably get another bunch from him, I'll ask him to pinch off some leaves.

Thanks for the airport options. I'll PM you if I can get my buddy to plan a trip with me.

[CTMIAMI]

Check your seedling for smell. I say that 1/2 of openly pollinated in Florida of Mexican avocados get the smell. Some more than others

[CTMIAMI]

Checking on my Doni on Poncho it looks Beautiful



Also this Beta on Duke 7 seedling



Both as Mexican as Mexicola. Never expected the Poncho to do this. It is a slow growing seedling. Duke yes they are used in many places for rootstock.

[JakeFruit]

I picked several new & old leaves off the seedlings, crushed them, and there was no anise smell.

[CTMIAMI]

You know now is not 100 % Mexican.

[pineislander]

Carlos, I'm curious what you think about Choquette as rootstock? They were large seeds, and a storm knocked down 50 pounds at once so I had a lot of seeds at once to plant. They seemed to take grafts well.

[CTMIAMI]

I never planted Choquettes for rootstock I have no personal experience. It is a vigorous tree, but it should do well. If anything, I would guess it would make a large tree.