Tree Planting Recommendations from Urban Forestry Services, Inc.

Plant 2" caliper trees or larger.
All trees shall conform to most recent ANSI 260.1 American Standard for Nursery Stock. First limbs shall be 5' above ground or higher.
Excavate hole to 1" less than height of rootball and three times width of rootball. In heavily compacted ground, loosen all soil 10 feet from the planting pit, 24" deep. In poor soils replace or amend entire rootway to 24" deep. Guarantee positive drainage from pit. Slightly mound in heavy clay soils. Tamp bottom of pit under rootball thoroughly to keep tree from settling. Set tree a minimum 4' from sidewalk or center between curb and side. If no drainage is possible in the pit, install circle of perforated pipe in bottom of planting pit, or entire bed, and connect to storm drain.
Place root barrier flush against curb and/or sidewalk a minimum 6 feet in both directions if tree list, specifications, or arborist calls for it.
Minimize damage to balled and burlap rootballs when planting. Remove all wire, string, and burlap, or at least from top and sides of ball, only after placing in hold. Cut and spread roots to eliminate root circling for container stock. Remove all fabric from grow bag trees.
Set tree straight and rootball on solid ground. Top of rootball must remain 1" above finish grade.
Backfill hole half full with native soil and no amendments. Tamp soil to stabilize rootball. Finish backfilling and tamp again.
Form water dam with soil around planting site to hold water for deeper soaking at least 2' from trunk. Watering must penetrate and saturate the rootball to maintain tree and initiate new root growth.
Place Osmocota Plus 15-9-12 slow release retilizer or similar at manufacturers recommended rate evenly over the soil of the planting site. Cover minimum 2' radius area with 3" composted medium/coarse bark mulch. Pull mulch 3" away from trunk. Maintain mulch indefinitely and do not allow grass to invade.
Water immediately and thoroughly, twice/week during the first month, then once/week through the remainder of the dry season. Water a minimum of once/month during the second summer season.
Stake trees outside rootball and parallel to street. Use 2'x6' treated lodgepole pine tree stakes. Use 1" heavy chainlock tree ties or similar, and fix to post with wood screw. Remove after 1 year.