The Garden Guru: Now's the time to plant dependable Shumard red oaks

No tree that we grow surpasses Shumard red oaks for quality, beauty, longevity and dependability. They set the standard against which all other tree species can be measured. Since they’re coming into their peak season in North Texas, this would be a great time to give them a call-out.

Shumard red oaks (Quercus shumardii) are native to Texas and the entire South, all the way into Canada. Locally, you’ll find them growing in mixed pecan bottomlands and on chalky hillsides. About all they really require is ample space and fairly dependable moisture.

Given good growing conditions, Shumard red oaks are large shade trees. They grow to 50 to 60 feet tall and wide, and their trunks can reach several feet in diameter. Their leaves are the size of your hand, and they’re dark green all summer, turning to shades of red and burgundy before they fall in late November and early December.

Their branches are generally ascendant, which is a primary way of distinguishing them from pin oaks (Quercus palustris). Although the leaves of both varieties are similar in size and form, the lower branches of a pin oak hang downward, much like boughs on a Christmas tree. It’s a critical distinction, too, because pin oaks do not adapt to North Texas’ alkaline clay soils. They’re doomed to short lives punctuated by extreme iron deficiency. They should never be sold here, but they sometimes are, generally mistakenly as Shumard.

Texas red oaks are also quite similar in appearance to Shumard red oaks. They’re native to a broad area of the rocky Texas Hill Country. Their leaves tend to be smaller than those of Shumards, and they are generally found in multi-trunk clumps, where Shumard red oaks are usually single-trunked. These two types are equally well-suited to alkaline soils.

Because of their large size, Shumard red oaks are best used as specimen shade trees. Allow your tree ample room to grow to its full height and spread. Plant it no closer than 40 feet from power lines and the street, and keep it at least 30 or 35 feet from other trees and high rooftops. As with any massive shade tree, keep it at least 10 or 15 feet away from walks and driveways to prevent damage from its large surface roots.

Oaks often get the reputation of being slow-growing trees, and this one is no exception. However, if you choose your tree carefully, plant it immediately and care for it regularly, a Shumard red oak will grow two-thirds as quickly as a fast-growing "trash" tree but will live 10 or 20 times longer.

Fall is the best time to plant your new red oak. Container-grown trees will have all of their roots intact, so they’ll establish and take off more quickly. There is, however, a risk of getting a type of red oak that isn’t a true Shumard if you buy one in a pot. They’re decidedly more mobile, so they can be brought in from far greater distances. Balled-and-burlapped trees, by comparison, usually have local beginnings. If you do opt for a dug tree, however, be sure that it has a full complement of leaves and that it’s well on the road to recovering from the shock of being transplanted.

New red oaks should be planted at the same depth as they were growing in the nursery. Form a basin using the soil you have removed from the hole. That will allow you to water your new tree by hand every week for its first year. You cannot count on sprinkler irrigation to provide sufficient water.

Perhaps the biggest stumbling block home gardeners encounter with Shumard red oaks comes from trunk damage from borers and sunscald. The damage almost always affects new trees before they establish good canopies to shade their smooth trunks. Always wrap the trunks of new red oaks with paper tree wrap from the ground to the lowest branches. You’ll find it in hardware stores, nurseries and home centers. Leave it in place for 18 to 24 months to get your new tree off to its best possible start.

Other than the possible outbreak of borers, few insects bother Shumard red oaks. Occasionally you’ll see leaf and twig galls — abnormal growths that result from adult insects laying eggs within the leaf or twig surface. The gall is plant tissue that develops around the larvae. There is nothing you can do, but luckily, they don’t harm the plant.