Ornamental oak trees include trees such as the white oak, English oak or northern red oak. They are generally large shade trees with a full lush canopy. When planting ornamental oak trees, be sure that your trees grow the way you intend and that you do not plant them too close to overhead wires, other trees or solid structures. Ornamental oak trees are usually planted as young trees purchased from a nursery, and should be set in an area with full sun and well-draining soil.
Research your ornamental oak tree's mature height and spread. Each variety grows differently and knowing your tree's growth potential will help you determine how far apart to plant your trees.
Space them with plenty of room to reach their fullest potential. If for example, your oak tree has a mature height and spread of 50-80 feet, then space them so they are clear from any structures (e.g., house) by 25-40 feet on all sides of the planting site. Look up to be sure there are no overhead wires within 80 feet in any direction from the spot where the trunk is to be planted.
If you're not sure of the distance, call your local utilities department to come have a look at your site. If you are planting another similar oak tree, they will need 50-80 feet in between them so they both can reach their mature spread.
Space them so the ornamental oak trees will grow taller, rather than wider. If you plant your trees closer together, then they will not have as many lower branches and will not reach their mature spread. You can plant the trees within a couple feet of each other if you want since that is how they often grow in forests, but about half of the distance or more as discussed in step 2 may be more reasonable and be more aesthetically pleasing for the average homeowner. Still leave enough room for mature growth from structures or overhead wires.
Consider the roots, which generally grow as wide as the mature spread. If your tree has a mature spread of 50-80 feet, then stay about 40 feet away from septic tanks, main water pipes or basements. You may need to call a plumber or look at any permits your house may have at your local government office to map out where some of these underground obstacles are located.