A participant in a perennial class today mentioned fertilizers. She'd found that the local Wal-Mart isn't selling 10-10-10 (NPK) anymore, only 10-0-10 (eliminating the phosphorus that can be problematic in streams, ponds, and lakes). She likes to apply 10-10-10 around her garden every spring, she said. Another participant said that she'd found 10-10-10 at Lowes.
And I'm thinking, goodness, why would you want to spread fertilizer around shrubs and trees in your garden every year?
Annuals and edibles certainly need fertilizer (I use organic time-release and compost), but most shrubs, and trees should be quite fine with regular organic mulches, since we don't harvest them. Some herbaceous perennials will benefit from a bit of (preferably organic) fertilizer in addition to mulch, since we often do cut their flowers or remove their spent foliage.
Soil tests provide the most accurate information, of course, about your soil nutrient levels and degraded urban and suburban soils may need building up, to be sure.
But the most important thing to do is to keep the organic matter produced by your garden plants (leaves, twigs, etc) IN your garden, recycling it as either as mulch, compost, or both. That's what happens in natural ecosystems, after all.