One of the two main groups of oaks (along with the white group) is the red or black group. Trees in this group have leaves with pointed tips on divisions. Red oaks generally have fibrous roots near the surface, so are easier to transplant. They produce acorns generally every two years, termed “biennial maturation.” Hardy common examples in this group are the scarlet oak (coccinea), shingle oak (imbricaria), pin oak (palustris), northern red oak (rubra), shumard oak (shumardii), and the black oak (velutina).
The scarlet oak starts off with a pyramid shape, becoming more rounded with age. It can reach 75 feet high and 50 feet wide. The leaves can turn a vivid red in fall, as its name indicates, turning color later than many oaks.
The shingle oak also is called laurel oak, as its leaves resemble those of laurel. They turn a bronze to russet fall color. The bark is used to make shingles, so its other common name. This oak will tolerate some urban pollution. It produces less acorns than many oaks, only every two to four years, so is less messy in landscapes. With age, this oak reaches 50 to 60 feet high, and a little over half as wide.
The pin oak is one of the most popular seen in landscapes, as it tolerates a range of conditions. It can even tolerate wet soils and clay soils if not compacted. Pin oak is easily spotted in landscapes with its upward reaching top branches, horizontal middle branches, and drooping down lower branches. Over time the pyramid shape may reach 60 feet high and half as wide. The leaves turn a golden brown in fall and are held all winter. If soils are too alkaline, summer leaves may turn yellow with green veins.
The northern red oak may show similar leaf yellowing on alkaline soils as the pin oak, yet remains a top choice with red fall color. It is fast growing, with a rounded shape reaching 50 to 70 feet tall with age, and 40 to 60 feet wide. This red oak tolerates city conditions better than many oaks.
The shumard oak is another adaptable oak for a range of conditions, from wet to dry soils, salt, and air pollution. It, as the northern red oak, is fast growing. With age it can reach 40 to 80 feet high, and 40 to 60 feet wide. Fall leaves are an attractive bronze to deep red. The shumard oak tends to produce many acorns, which is good for wildlife but not as desirable in more formal landscapes. Being hardy to zone 5 (-10 to –20 degrees F) makes it not as hardy as many other oak species.
The black oak is attractive with its shiny leaves similar to those of the northern red oak, but is less commonly found in nurseries, is slower growing, and is difficult to transplant. This long-lived oak, none-the-less, is desirable and existing trees should be saved during construction. The rounded shape to 50 feet high can vary widely among individual plants.Many red oaks are native to this country, so even if you don’t plant them, you may find them while you’re on woodland walks. You often see them in parks and large landscapes. If you have oak furniture or wood in your home, it well may be from a red oak.
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