Red oak (Quercus rubra), sometimes called northern red oak, is a sprawling shade tree that grows 50 to 75 feet high with a spread of 50 to 75 feet in U.S. Department of Agriculture plant hardiness zones 4 through 8. It grows at a medium to fast rate, meaning from 12 to more than 25 inches a year, and will tolerate the pollution of urban growing conditions. The chief concern is planting it in a location that can handle the large spread of its roots. There are no major differences or unusual practices for planting red oaks than for other tree species.
Timing, Seedling Selection and Location
Since red oak trees establish new roots slowly, the best time to plant them is in early spring just before or just as plants in your area are beginning new growth.
Buy the largest possible seedling from a local nursery. Seedlings grown elsewhere may not thrive in your climate. If it's a bare root tree, look for a taproot with six to eight side-roots at least 1/8-inch wide growing on the taproot. If it's a container tree, it should be no smaller than 3/8-inch wide at the base.
Large, spreading roots of a red oak can undermine above-ground structures. The [Sacramento Tree Foundation](http://www.sactree.com/pages/165) advises planting it at least 8 feet from a sidewalk or driveway; 15 feet from a building foundation, swimming pool or septic tank; 25 feet from another tree; and 30 feet from an overhead power line.
Sun and Soil
Plant red oak in full sun.
Red oak will grow in dry to medium soil with a pH from 4 to 7. It prefers finely textured, fertile, sandy soils that drain well. Native soil is generally fine for red oak. Do not add sand or organic matter to the planting site. The exception: Add 25 percent peat moss if you have rocky or clay subsoil. Do not add fertilizer. Avoid planting in depressions or in shallow, rocky or poorly drained soils.
Remove grass in a circular area 3 feet wide where you plan to plant the tree, and turn up the soil in that area.
Root Ball Seedlings
For a seedling purchased balled and burlaped, or in a nursery container, dig a shallow, bowl-shaped hole as deep as the root ball is high or from 1 to 2 inches shallower and at least three times the width of the root ball.
Remove the burlap or wire basket after you put the root ball in the hole, to incur less damage to the roots. Cut wire baskets into pieces with snips, then pull them out with pliers. If a loose root ball prevents you from removing burlap, slit it and peel it away from the roots below the top of the soil. To remove the root ball from a nursery pot, tap the sides of the container to loosen the soil, tip the seedling on its side and gently slide the tree out; do not aggressively pull it out by the trunk. If a container-planted seedling appears root-bound, with roots tightly encircled, cut an X in the bottom as well as a few vertical slices along the sides to loosen the roots; use a sharp knife disinfected with rubbing alcohol.
Sit the collar, where the root meets the stem, level with the ground or 1 or 2 inches higher.
Bare Root Seedlings
Nurseries sometimes sell bare root trees or you may have bought one online. After you have unpacked your tree, carefully untangle the roots and soak them in water for three to six hours. Don’t let them dry out.
Dig a hole large enough so you can spread the roots out and so that the crown of the tree, that point where the roots meet the stem, will be level with the ground.
Finish adding the soil. Construct a circle of soil several inches high around the diameter of the planting hole. Fill this basin with water and let it soak in.
Mulching and Watering
When you're finished planting, add a 2- to 4-inch layer of straw, grass clippings, bark or wood chips over three times the diameter of the root ball or the spread of a bare root tree. Keep the mulch from touching the base of the tree. Add to the circle of mulch as the tree grows. The mulch keeps the soil cool and moist, deters mowers and suppresses grass and weeds that may compete for nutrients.
Keep the soil around your newly planted seedling moist but not soggy by watering slowly at the drip-line, the outer spread of the tree’s branches. Water every seven to 10 days in dry weather for the first year. Add the water slowly, not all at once.
If the sun hits the stem in winter, wrap paper around the stem from the bottom up for one or two years.