Each of them love to dig. Within a few short months the tilth of the soil improves dramatically merely by adding organic material to the top of the soil. The greatest enemy to the health of our garden may be salt. We get it as residue from our water as it evaporates, from our chemical fertilizers, and it even leaches out of the cement around our homes. Adding organic mulch neutralizes the effects of the excess salts by the release of acids as it breaks down.
More plants die due to over-watering than drought, ask any professional gardener.
When a city ordinance required that the irrigation water be turned off during a severe drought the plants that I was caring for did not all die. In fact many started to grow much better. For years people have been selecting plants that are equipped to handle the vagaries of our climate. The problem is that, as a group, we just don't know enough about the plants in our gardens. To remedy this problem we are developing a series of lists, pictures and descriptions detailing the needs of our plants.