This answer may seem long, but I think all these points are important.

If you want to be sure what nutrients are needed, you'd have to have a soil test done. There's no other way to accurately tell what nutrients are needed.

In this part of the country, our soil is typically fairly nutrient rich (at least relative to what trees and shrubs need). Clay is often very nutrient rich because it can hold onto nutrients better than other soil types.

Trees can usually get all the nutrients they need without supplemental fertilizer, especially in a wooded area (where leaves and stuff are allowed to compost naturally). In lawns, trees occasionally need extra fertilizer.

Using fertilizer when it's not needed can be detrimental to trees and shrubs. I wouldn't use an all-purpose fertilizer on woody plants without a soil test or at least without a good indication that it was needed.

In cases where nutrients are needed, the most common nutrient need, by far, for better tree and shrub growth is nitrogen. If you do use a fertilizer without a soil test, it should have a high nitrogen-to-other-nutrient ratio (The first number should be considerably higher than the second two numbers). Blood meal can be great (except that I've heard it may attract some varmints).

Compost and compost tea are almost always a great source of nutrients. They can feed your woody plants without many of the pitfalls other fertilizers may present. The only two things that I can think of that could possible go wrong with compost are 1. if you have a tree that's already growing very fast and additional nutrients cause spindly growth, and 2. if you piled compost up year after year it could eventually smother the root system of trees or shrubs as layers built up.

Thanks Brandon!... very good information.

For the few evergreens that I fertilized, I used evergreen tree spikes. Not sure if those are much good, but it is on a steep slope, and I fear that surface fertilizer would wash away.

I try to under-fertilize when I do use the stuff.

Thanks again (you don't seem this chatty in person!)

Kelton

Tree spikes don't even distribute their fertilizer in the root zone and are therefor pretty ineffective. They are also expensive compared to the same amount of fertilizer in granular form. Thirdly, they aren't formulated for your soil. Many more small pockets with a small amount of the correct fertilizer might work better on a slope, if the trees really need fertilizer.

You probably met my shy personality, Brandon 5-3/8. He is the quite one.

OK... I wondered about the problem with "distribution" on those spikes. I just figured that the developer considered that factor as well.

I had thought about just spiking some holes around the drip line and putting the appropriate fertilizer granules in those holes.

Oh well, in the future, maybe I'll just not fertilize at all! Let the earthworms do their thing.

I think I've mentioned before- the earthworms in Tennessee are FAR more powerful than those found in Florida. Grabbing an earthworm up here feels like snake wrestling!

You know, I've noticed a big difference between the way different worms feel around here. Most of the time, when you pick one up, it's just completely limp, but then sometimes you'll get a real fighter. I don't know what the difference is. They look the same (or at least to me). And, it's not size. I picked a little one up the other day that physically protested my assault on his peaceful afternoon in the mud.