1. Dig a hole three to five times the width of the rootball and no deeper than the rootball. The walls of undisturbed soil should be rough and tapered, as shown.
2. Set the plant on undisturbed soil in the center of the hole, with the top of the rootball at or slightly above soil level.
3. For trees that need staking, sink two wood stakes (2 inches in diameter or 2 inches square) at least 6 inches into undisturbed soil on opposite sides of the plant, outside its canopy.
4. Partially backfill the hole, firm the soil, water thoroughly, and finish backfilling.
5. Build a small berm of soil around the rootball and water thoroughly.
6. Mulch with a 3-inch layer of compost or ground bark; mulch should not touch trunk. If you used stakes, loosely tie them to the plant.
Soil with caliche underneath
Ideally, the workable soil should be 18 to 24 inches deep; if it isn't, you may have to bring in more topsoil. Imported soil should be as similar to your native soil as possible and free of weed seeds, rocks, and debris. If in doubt, consult your nursery, landscape professional, or extension service.
1. Follow step 1 above.
2. Drill or dig through the caliche layer with a soil auger or jackhammer to create two drainage chimneys at opposite ends of the hole as shown.
3. Set the plant in the center of the hole, staking it if necessary.
4. Add backfill as described in step 4 above.
5. Add topsoil as needed to make it level with the rootball.
6. Build a berm as described in step 5 above; soak the plant thoroughly.
7. Apply mulch and tie stakes as described in step 6 above.