you can take a broom handle for example and poke holes around the tree drip line and fill the holes with your fav fert and have instant fert sticks of your own.

I dont know if its better or not and how long it lasts, but I do this often if I happen to remember to do so.

Are any professional landscapers using fertilizer spikes for trees?

Consider simply lightly fertilizing with a 6-6-6 every couple months during the growing season. If its a native, it probably doesn't need any, especially if you already fertilize your grass some.

Gary

A lot of the so-called slow-release fertilizers do not last as long as advertised in Florida. Therefore, you may end up with a heavier concentration than you would like to have.

Susan