Maple trees bring beautiful color and dependable shade to yards in almost all growing zones. Relatively disease-free, with warm green leaves, small seed pods and roots that seek deep locations, spreading disruptively under pavement only when crowded, maples make good yard trees and street trees. Fall color ranging from pleasant to spectacular adds to the list of reasons to include maple trees in your landscaping. The only caution is knowing the correct planting intervals for healthy tree growth.
In general, trees need to be planted at intervals approximating the size of their leaf spread. This allows major roots to establish and take in enough nourishment for the tree. Many gardeners and nursery workers calculate mature root spread as equaling or slightly exceeding leaf spread. For a row of trees that at maturity have an approximate leaf spread of 40 feet, trees should be planted no closer than 40 feet apart. This distance can be decreased slightly if very thick screening is wanted (as for traffic on an elevated highway), but it is important to allow for mature growth.
Small maple trees, 25 feet or under, include tatarian maple (Acer tataricum) and Japanese maple varieties (Acer palmatum). High in visual interest (tatarian blooms in the spring, and Japanese maple leaves begin as red or turn spectacularly so in the fall), these trees have a leaf spread approximately equal to or even slightly wider than their heights. Some varieties of Acer palmatum are small enough to be treated as ornamentals; some are even miniaturized as bonsai.
The smallest of the middle-sized maples is trident (Acer buergerianum), ranging between 20 and 30 feet in height. Big leaf maple (Acer macrophyllum), canyon maple (Acer grandidentatum) and several kinds of red maples (Acer rubrum) complete this category, members of which run as large as 50 feet in height. Some red maples run larger; your local nursery will help you choose the right size for your space.
This grouping includes maples with some of the most familiar names, including sugar maple (Acer saccharum). Rock maple, better known as black maple (Acer nigrum), can reach heights of 80 feet or more, as can silver maples (Acer saccharinum). Norway maple (Acer platenoides), reaching heights of 60 feet or more, may not be the biggest of the maples, but it's particularly broad spread and dark leaves make it seem very large.
Other Planting Considerations
In addition to wanting adequate space, maple trees by and large do best in full sun. Take into account differing heights of different kinds of maple trees if you are planting a group of them; shorter maples will welcome the sun as much as larger ones, which should be spaced far enough away so as not to shade them. Ask questions about the specific performance of the kind of maple you want to plant. The specific variety (red maples include "Red Sunset," "October Glory" and others) may have a particularly large leaf-spread, a narrow silhouette or other considerations you need to factor into planting. Taking your time at planting will pay off in the long run. Maples can live 100 years or more.