Your bare root Arizona cypress (Cupressus arizonica), suitable for U.S. Department of Agriculture plant hardiness zones 7 through 9, may just be a sprig at planting time, but don't let its diminutive size convince you to plant it near your home's foundation or next to the driveway. Just as a sweet baby boy becomes a hulking teenager in what seems like no time flat, this evergreen, which begins as a slim blue-green column, eventually grows into a broad pyramid-shaped tree 30 to 50 feet tall and 15 to 30 feet wide. Bare root evergreens are commonly only available as seedlings, and are sold for planting in late winter and early spring.
Unwrap your bare root Arizona cypress as soon as you get it home. Evergreens need constant moisture to support their foliage, since they don't go fully dormant like deciduous trees, so are only sold bare root when very small.
Examine the roots and the foliage. An Arizona cypress has a central tap root and many small lateral roots. Roots are often trimmed for shipping and may have been dipped in blue hydrating gel to keep them moist. Return or discard any seedlings with brown foliage -- it doesn't green back up -- or roots that are tightly wrapped around each other, brittle or mushy.
Put the roots of the seedlings in a bucket of water for at least a few hours, but no more than 18 hours, so they are fully hydrated.
Put on garden gloves, and clear sod, rocks and weeds from a space in full sun that has enough room both overhead and around it for the mature size of the Arizona cypress. Allow for enough space to plant your seedlings 6 feet apart on centers if you want to create a windbreak or screen that grows in to create a wall of blue-green foliage.
Dig a hole that is just as deep and twice as wide as the plant's root system. Since an Arizona cypress has a tap root, don't make a mound of soil in the bottom of the hole to support the roots. Instead, hold the plant so the point where the roots end is at soil level, and scoop loose native soil into the hole so it fills in the spaces between and around the roots, up to the level of the surrounding soil.
Water the plant well to settle the soil, then make any adjustments needed so the plant is perfectly vertical and the soil is at the right level.
Provide at least an inch of water a week -- adjusting for any rain -- so the soil stays moist, but not soggy. Arizona cypress trees are drought tolerant once they get started and need only 10 to 12 inches of water per year.