Many people place oaks in a somewhat more revered category than other trees. Mighty oaks are used as a symbol of things that are strong, longlasting and reliable. There are about 400 species of oaks that grow to tree-size worldwide, 58 of which grow in the U.S., and 38 of those grow in Texas. There are at least 10 species of oaks that grow in the Edwards Plateau.
Oaks are generally classified as in the white oak or red oak group; the colors themselves are not really meaningful.
White oaks are characterized as having leaves with either smooth edges or, usually, rounded lobes (bumps along the edge of the leaves) without bristles at the tips of the lobes. Their acorns grow to maturity in one year, and usually sprout in the fall. The acorn cups have a knobby appearance on the outside and are smooth on the inside. Next year’s buds on white oak branches are not sharply pointed.
Red oaks, by contrast, have lobes with points along the edge of the leaves and bristles at the tip of the points. Their acorns take two years to mature (become mature in their second fall) and usually sprout in the following spring. Red oak acorn cups are smoother than white oaks on the outside and are densely hairy on the inside. Their next year’s buds are usually sharp pointed.
White oaks have plugged cells or vessels which prevent flow of fluids from one part of the wood to another, and are therefore the wood of choice for making wine barrels. Red oak heartwood is permeable and therefore not suitable for wine barrels.
Oaks are wind-pollinated with the female flowers tiny and inconspicuous at the junction of the leaves and the stem. The male flowers are in dangling, bead-like strings that hang from the twigs and are called catkins. They appear as the leaves are forming in the spring.
Of the common oaks around here, only Blackjack oaks and Spanish oaks (also known as Texas red oaks) are in the red oak family. All of our other oaks: Lacey oaks, Chinquapin oaks, Shin oaks, Post oaks and Live oaks, are in the white oak family. (Some experts put live oaks in a separate group altogether, but most call them white oaks). If we stretch our area a little to include the rest of the Edwards Plateau, we can add to the above list Vasey oak to the west and Bur oak and Shumard oak to the east. Vasey and Bur oaks are white oaks, and Shumard oak is a red oak.
Oaks in general are slow growing, and slow growing trees tend to be the strongest, although Spanish oaks seem to be brittle and break off in wind storms more often than most of the others.
It is possible to grow oaks from acorns, although many acorns are not viable because a small wasp has laid its eggs in the acorn and the worm thus hatched eats the inside of the acorns. Put a handful of acorns in water and those that float are not viable.
Root sprouts, which are little trees that are connected to the roots of a mature “mother” tree usually grow faster and have a better chance of making it than trees growing from acorns. That is largely because the former are growing from a network of mature roots much larger than itself and so it can withstand drought and any other stress much better. If you see root sprouts coming up under and around a mature tree, if you cage them before the deer find them, you will have a much better chance of having a healthy new tree than planting an acorn or planting a nursery tree either for that matter. When most folks think of oaks, they tend to think about oak wilt. Here are some of the basics about oak wilt. We lose many more live oaks to oak wilt, by far, than other oaks. This is mainly because naturally growing live oaks tend to have interconnected roots, so when one tree gets oak wilt, its neighbors are likely to also. Other oaks, including other white oaks, tend not to be as interconnected as live oaks.
Most infected live oaks tend to die within three to six months. Red oaks never survive and frequently die within four to six weeks.
For more detailed and reliable information about oak wilt, go to
I have noticed around my place that the extreme cold weather we had (<5 deg) appears to have killed a lot of live oak leaves, many dropping already. I have hopes new leaves will appear as normal later in the spring. This may be only a local phenomenon.
Until next time…
Jim Stanley is a Texas Master Naturalist and the author of the books “Hill Country Ecology,” “Hill Country Landowner’s Guide” and “A Beginner’s Handbook for Rural Texas Landowners.” He can be reached at