_gonzo_

As more or less stated, often too much attention goes to the visible part of the plant instead of the unseen foundation.

In the end improving the "soil" and therefore the roots, often requires both immediate and long term results for a tree's overall health. I am a fan of organics for this reason simply because (in So. Florida) I see great results.

I use about 60% Turface MVP, about 20% peat, and depending on the plant, 20% either fine bark chip, loam, or sand. All mixed with small amounts of various (beneficial) fungi spores as a basic soil.

I then use liquid organic fertilizers with nutrients that are chelated, meaning instantly available to plants and also employ bi-weekly foliar feeding (sprayed on and under the leaves) as many plants benefit from the underside of their leaves for nutrient intake.

If you are using various fungi to assist your root system you are also feeding them. I find that either 8-4-4 or 10-8-8 fertilizers seem to do the trick.

Finally, something with a bit of molasses (for instance) seems to be good. Whether this helps the plant, fungi or both convert simple sugars or just offers them directly, I don't know, but it does seem to work.

Cheers,

_gonzo_