The red oak tree

Contents

Red oaks: Where and how they grow

The searing heat of the summer day seemed inescapable. I tramped through the tall grass and headed for shade. A grove of oak trees looked promising.

Reaching the hillside grove, I leaned against one of the massive trunks and wiped my brow. A heaven-sent breeze rustled the leaves above, and the sanctuary of the oak grove was, for the moment, the most beautiful spot on earth.

The oaks that created this oasis on the prairie were black oaks. Black oak trees belong to the red oak group. In this column we’ll take a look at the red oak group — who they are, where they grow, and what the future holds for islands of oak groves in a sea of suburbia.

The red oak group as a whole has two main characteristics: pointed leaves ending with small bristle tips, and acorns that take two years to develop. Each species within this general group shares these two traits; each has additional, unique characteristics that separate it from the others. Fortunately for us, it’s easy to learn the distinguishing characteristics.

The group’s namesake, northern red oak, is a tall forest tree that favors deep, moist soils on upland sites. Northern red oaks can reach more than 100 feet tall in good conditions, with trunks three or more feet in diameter. These stately trees stand out in the forest by their beautiful bark. It’s dark at maturity, with silvery flat stripes running up and down the tree. These were described to me years ago as “ski tracks” and that image has stuck in my mind ever since. Look way up the trunk of a tall red oak tree, and you’ll see the tracks.

The leaves of northern red oak have between seven and 11 bristle-tipped lobes. These can be tricky to distinguish from some of the other red oaks. The acorns, though, are a dead giveaway. They’re large — about 1½ inch long, and they seem to bulge out of the acorn cap. This cap looks like a beret atop a person’s head.

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You may see “mini” red oak acorns fastened tight to the tree. These are next year’s fruit. As with all members of its group, the northern red oak acorns remain on the tree and take their time maturing. They will ripen and fall the second year.

What’s red about the northern red oak? You have to cut into the bark to see. The inner bark is pinkish more than red, but quite distinctive in freshly cut wood. Otherwise, the only red thing about the red oak is the autumn foliage. A beautiful red it can be, too.

Black oak is another member of the red oak group. Although similar in many respects to northern red oak, it possesses, as Donald Culross Peattie wrote in “The Natural History of Trees,” “a rough, unbending grandeur of its own.”

Black oak can grow tall and straight like northern red oak, but it can tolerate sandier, drier and coarser soils than red. It can grow in open, dry savannas and hills made of porous glacial till. In these conditions, black oak is often a gnarled-looking but picturesque tree.

At first glance, the black oak leaves are quite similar to northern red oak’s. Each leaf has seven to nine bristle-tipped lobes. Black oak leaves, however, have deeper sinuses, or indentations, between the lobes. Turn over a black oak leaf and look closely — there’s a layer of fine, rust-colored “fuzz” underneath. You might need a hand lens to see this.

And while you’ve got that hand lens out, look at the acorns. They, too, are fuzzy, particularly inside the acorn cap. The scientific name Quercus velutina refers to this velvety characteristic. Black oak acorn caps, unlike the tight berets of red, are shaggy and bowllike, covering up to one-third of the nut. The caps also have small, overlapping scales that look like shingles on a roof. Further, if you cut open the nut with a pocket knife, you’ll see that it’s a distinctive yellowish color.

Black oak bark is similar to that of northern red oak, ski tracks and all. The inner bark, like the acorn meat, is yellow to orange — not at all like the pink-tinged inner bark of red.

Pin oak is another type of red oak that grows in our area. It’s not native to Kane County, but it’s common in landscape plantings. Pin oak leaves are similar to the previous two species, but the sinuses are very rounded and very deep, reaching almost to the middle vein of the leaf.

The main trunk grows straight. For this reason, people like to plant it as a street tree. The lower branches droop, but overall the tree has a pyramidal shape. Numerous short spurs grow from the branches; these are the “pins” of pin oak. The bark is light and thin — quite unlike the dark, tough bark of northern red or black oak.

Pin oak’s scientific name Quercus palustris means “oak of the swamp.” This species can tolerate wet clay flats, often referred to as flatwoods. It’s a tree well suited for bottomlands, whereas the other red oaks in our area are upland dwellers.

Often, pin oak leaves are light green and kind of sickly-looking, indicating the tree is suffering from an iron deficiency. This problem led the late Dick Young, author of “Kane County Wild Plants and Natural Areas,” to look askance at the use of pin oaks in landscaping.

“(They are) widely planted for ornamental purposes that often backfire,” Young wrote. “We commonly see this yellowing, skeletonized, nursery-recommended oak as a bleak front yard emblem of wasted money and hope.”

Best to let pin oak grow in clay-lined flatwoods where it does best.

Close kin to the previous oaks is Hill’s oak. It shares leaf characteristics of both black and pin oaks, and the bark is similar to that of pin oak. Hill’s oak differs mainly in its fruit. The acorn is uniquely elongated with a pointed base. There’s considerable hybridizing between these species, and you may find individuals with a mixture of features.

The future of oaks

Red oaks were once numerous in Kane County. But just as with white oaks, the red oaks are in serious decline. Only ten percent of the county’s original oaks remain, and there are scant few seedlings to build new generations of these great trees.

The challenges to oak regeneration are formidable: loss of habitat, competition with invasive species, and an increase in herbivores. When the tall, stately oaks fall, there are few progeny to replace them. Turf grass and asphalt are not inviting to sprouting acorns. Invasive species that shade out seedlings. Saplings are browsed by deer. The shifting climate and change in soil conditions contribute to the stress on oak trees. All these factors have taken a tremendous toll on our native oaks.

In my mind’s eye I return to the oak grove on the prairie where I sought refuge from the heat. I remember the venerable, old trees and the comfort they gave on that hot summer day. I listen in my memory for the sough of their summer leaves. Our long-ago ancestors called these sacred groves, and I understand why. These are special places, and priceless trees.

Valerie Blaine is an inveterate oak nut, and a naturalist with the Forest Preserve District of Kane County. Email her at [email protected]

Meet the Northern Red Oak

Writing by Whit Beals

Have you ever found yourself struggling for traction on a dry slope while on a fall walk in a hardwood stand? The cause of that slipperiness might have been freshly fallen Northern Red Oak (Quercus rubra) leaves, which have waxy surfaces, or an abundance of the tree’s acorns, which in some years cover the forest floor with “nature’s marbles.” Both the acorns and the leaves tie to the oak’s evolutionary strategy.

Red oaks evolved in concert with the now extinct Passenger Pigeon. It is estimated that 2 to 5 billion of these plump birds once inhabited the eastern forests. Their primary fall food was red oak acorns, and they would descend on forests in the midst of heavy acorn crop years—called mast years—in such abundance they would break off oak branches, building kindling on the forest floor. Similarly, the waxy oak leaves are fire prone once dry. This adaptation, combined with the life history of the Passenger Pigeon, helped create conditions for surface fires that oaks can often resist, but that may kill competing species.

You can spot red oaks in spring, when beautiful pink leaves covered in silky down emerge from the trees’ buds. Keep an eye out for them as you explore the woods this season.

Leaves

Leaves have pointed lobes, and are five to ten inches long and four to six inches broad. In summer, leaves are a dark green, and they turn a rich red or brown in fall.

Bark

Northern Red Oak’s distinct bark makes for an easy way to identify the tree species. Its bark appears to have irregular shiny stripes—they resemble downhill ski trails streaking a distant hill—between rougher ridges. A few other oaks have bark with this kind of appearance in the upper branches, but the Northern Red Oak is the only one with striping all the way down the trunk, except in trees of very large diameter when the bark becomes rougher at the base. Red oaks often hybridize with black and scarlet oaks, but the hybrids’ “ski trails” are apparent only in the upper branches.

Age and Size

In forests, these trees grow straight and tall to a height of about 100 feet, though exceptional trees will reach 140 feet. Their trunks reach up to 40 inches in diameter. When they grow in the open, red oaks don’t get as tall but they can develop stouter trunks, up to six feet in diameter. Trees may live up to 400 years according to the US Forest Service.

Wildlife Habitat

While the acorns are bitter, at least to human taste buds, years with high acorn yield can be a great benefit to many acorn-eating species of birds and mammals, including jays, wild turkeys, grouse, mice, chipmunks, squirrels, raccoons, bears, and deer. The “boom and bust” cycles of small-mammal populations generally coincide with high and low acorn production.

Growing Conditions and Timber

Northern Red Oaks grow rapidly and are tolerant of a variety of soils and site conditions, though they prefer well-drained lower slopes and stream bottoms. A typical southern New England woodlot might have drier sites hosting black, scarlet, and white oaks, with red oaks growing at lower elevations where the soils are deeper and moister. Red oak also persists onto warmer, drier sites in some northern portions of the region.

The tree produces very durable timber that is commonly used in cabinetry, furniture, interior trim and flooring, and is a particularly popular flooring choice.

Red oak also is the most financially valuable timber on NEFF’s approximately 29,000 acres of Community Forests even though it comprises just 20 percent of the total sawlog volume. Red oak, although slightly less abundant than white pine on NEFF’s lands, sells for about three times the per-unit value of the pine. As a result, red oak forms about 36 percent ($11 million) of our total value of standing timber ($33 million).

Red Oak

Quercus rubra

The red oak is one of the largest and most important timber trees. One of the fastest growing of the oaks, it attains a to 80 feet and a diameter of two to three feet. It has a wide, spreading head with few far reaching branches. Found growing over southeastern Canada and the northeastern United States, it reaches west to central Minnesota, eastern Nebraska and Kansas. It is found over most of Iowa on a variety of soils, except on the drier clay uplands. It prefers moist, rich soils on north, east or northeast exposures.

The tree has a single, lobed leaf with seven to eleven pointed or bristly-tipped lobes. The lobe sinuses reach one-half way to mid-vein. The leaves are thin, firm, dull green above, yellow-green below, varying considerably.

The fruit is a large, broad, rounded acorn with a very shallow disk-like or saucer-shaped cup or cap.

The twigs are small, slender, greenish brown to dark brown. On young branches the bark is smooth and gray to greenish. On the trunk it breaks into long, narrow, shallow ridges flat and smooth on top. The underbark is light red.

Leaves:

  • Have seven to 11 toothed lobes that are separated by sinuses extending about halfway to the midrib.
  • Contain tannin, a substance that makes the leaves leathery and hinders decomposition.
  • Dark red, fading to brown but may remain on the tree well into the fall.


Branching: alternate

Bark: reddish brown when young; mature tree is dark, furrowed and often laced with broad shiny strips (ski trails).

Height: 70 to 90 ft.

Trunk Diameter: 2 to 4 ft.

Longevity: 300+ yrs.

Tolerance: intermediate

Range: eastern U.S. except for the south Atlantic and Gulf Coastal Plains

Fun Facts: Acorns provide a food source for numerous birds and animals: Ruffed grouse, nuthatch, blue jay, wild turkey, red, gray and fox squirrels, bears, deer, raccoons.

Question: How many root beer barrels could you make from a red oak tree? Answer: None – red oak has big pores, so all the root beer would leak out.

Identify Another Tree

Environmental Studies

One of the most dominant of the northern oak species, the red oak, lives throughout eastern North America. It is the state tree of New Jersey and the arboreal emblem of Canada’s Prince Edward Island. It is very tough and planted throughout cities and along streets. Its natural habitat includes moist woods, valleys, and slopes.

Physical characteristics

Photo by Julia Giza

Leaf: The leaves are smooth and lustrous. Leaves are deciduous, alternate, elliptic, and 10–25 cm long and 8–15 cm wide. They have a few irregular bristle-tipped teeth, and the sinuses usually extending less than 1/2 distance to midrib. The colors range from light to dark green in the summer, to orange/red in the fall.

Flower | Seeds: Male and female flowers are borne in separate catkins on the same tree. Acorns fall and mature within two years.

Trunk | Bark: Dark reddish grey brown, with broad, thin, rounded ridges, scaly. On young trees and large stems, smooth and light gray. Rich in tannic acid. Branchlets slender, at first bright green, shining, then dark red, finally dark brown. Bark is brownish gray, becoming dark brown on old trees.

Life span: Red oaks can leave up to 500 years, but usually live to about 300 years.

Ecological characteristics

The red oak grows in rich and well-drained soil. The wood is very porous and resistant to decay. The tree produces acorns in which many types of wildlife eat.

Distribution range

Importance to the ecosystem

The red oak is a producer. It uses photosynthesis to produce energy for itself and also converts carbon dioxide to oxygen. The tree provides many types of birds nesting opportunities and homes. The tree produces acorns in which many kinds of wildlife consume.

Relationship with other species

Non-human: It is a provider of food for all kinds of animals. It also serves as shelter for many birds and mammals.

Humans: Red oak wood is one of the main woods used for timber in the eastern United States. Because of its ability to tolerate many conditions, it is planted in many cities and urban areas. It is often planted for landscaping.

Pests: Two diseases that affect the red oak tree are oak wilt and oak decline. Oak wilt is caused by a fungus and in the eastern U.S. it kills thousands of red oak trees whether they be in forests or cities. The oak wilt fungus can be carried from tree to tree by insects or connect through root systems. Oak decline is a much slower tree disease that can take up to five years to kill a tree. It is not just one disease but really a combination of several different stresses on a tree such as drought, fungi, boring insects or late frosts in the spring. The biggest pest for a red oak tree is the red oak borer, but it does not kill the tree. It is the borer’s larvae that first damages the tree by burrowing into crevices in the bark.

Other interesting facts

  • Red oaks can thrive in about any kind of soil.

  • In the fall, red oak leaves turn to beautiful colors of red and orange.

  • The red oak wood has very large pores.

Photo by Julia Giza

Page drafted by Charlie Marshall

Northern red oak

Northern red oak (Quercus rubra) photo: John Hagstrom

Tree & Plant Care

Prefers a well-drained, rich woodland site. Best in sandy, loam soil.
Tolerant of air pollution and salt.
Prune oaks in the dormant season to avoid attracting beetles that may carry oak wilt.

Disease, pests, and problems

The Northern red oak develops chlorosis symptoms in high pH soils.
All oaks are suceptible to oak wilt.
Galls and mites are common insects, but not harmful.

Disease, pest, and problem resistance

Tolerant of black walnut toxicity.

Native geographic location and habitat

C-value: 7
Native to eastern and south-central North America.

Bark color and texture

Young trunk and branches grayish turning dark gray with age.
Mature bark is bark gray with flat-topped ridges. Lower bark can be blocky or furrowed.

Leaf or needle arrangement, size, shape, and texture

Alternate, simple leaves with 7 to 11 lobes. Each lobe has a bristle tip.
Dull dark green upper surface and slightly paler beneath in summer changing to a russet red to bright red fall color.

Flower arrangement, shape, and size

Borne separately on same tree. Male flowers are hanging catkins, female flowers are tiny spikes in the axils of the new leaves.

Fruit, cone, nut, and seed descriptions

Acorns are medium brown, 3/4″ to 1 inch long, and barrel-shaped. The cap is thin, flat, with appressed scales barely enclosing 1/4 of the nut.

Texas Red Oak Tree Information

Texas Red Oak Tree Information (Quercus buckleyi).

A good looking tree for the southwest and other parts of the west. I love this for its hardiness and overall looks. Many folks do not realize Red Oak trees will do well here particularly the Texas Red Oak. It is native to south-central Texas but can be grown in most southwestern cities.

Yes, they do like water and can tolerate the hot desert sun they can also be planted in shady conditions. It a bit smaller than the Eastern or Shumard Red Oaks as it will grow about 50ft. tall and 30 ft. wide. This makes them a great tree for smaller yards or landscape areas.

It is deciduous meaning it will lose its leaves in winter but has a burst of orange, red, and bronze colored leaves in fall from about mid-October until early winter.

What about maintenance?

They produce acorns that will fall in early spring so there is cleanup during the spring seasons. Also, foliage cleanup in late fall. Occasional trimming to keep branches from getting too wide.

What about insects and diseases on Texas Red Oaks?

It is a hardwood species tree that makes it difficult for insects or borers to dig into. But if the conditions are right it may develop Oaktree wilt. This is a fungal virus (Bretziella fagacearum) that attacks Oak trees in regions where there is lots of rainfall. Spraying with a tree fungicide will remove this fungus.

Read more on the Oaktree wilt over at Wikipedia.

Texas Red Oak fall foliage.

The Fall Foliage of the Texas Red OakA Texas Red Oak Tree about 10-13 years of age. During fall Season. A Texas Red Oak during the summer season.

Information on the Live Oak tree here.

The Shumard Red Oak looks similar but grows much larger see photos and information here.

The Mighty Oak: Oak Trees of the Chicago Region

How to identify and care for the mighty oak trees of Illinois

At Hendricksen Tree Care, we are not only professional arborists, but also tree enthusiasts who are dedicated to caring for the many types of trees found throughout the Chicago area. For the first feature of our blog series highlighting the many different trees of Chicago, we start with the mighty oak tree. The oak tree has a long history in the Chicago area. Before Chicago was established and developed as a city, oak trees were by far the most common type of tree in the area. There are twenty species of oak tree that are native to Illinois, including the white oak, swamp oak, shingle oak, and Chinkapin oak. In 1907, school children voted to make “native oak” the official state tree of Illinois and in 1973, the white oak became the official state tree.

In this guide, we will cover general information about oak trees, identify oak trees native to the Chicago area, discuss how to care for oak trees, and cover pests and diseases that commonly affect oak trees. If you have a beautiful old oak tree on your property, our arborists at Hendricksen Tree Care provide tree care and maintenance services to protect your oaks against pests and diseases.

Basic Characteristics of Oak Trees

There are over 20 species of oak trees in Illinois, if you are concerned about an oak tree on your property call a professional arborist such as Hendricksen Tree Care today

Oak trees are large trees that are found throughout the world in the Northern Hemisphere including North America, Asia, North Africa, and Europe. There are an estimated 600 species of oak tree that fall under the genus Quercus, and the highest number of oak species is in North America. The United States alone is home to around 90 different oak species, 20 of which are native to Illinois.

Oak trees can grow in different climactic conditions from cool temperate conditions to tropical climates. Most oak species are deciduous, meaning they lose their leaves every year, but there are some species that are evergreens. Oak trees are also monoecious which means that male and female flowers will bloom on the same tree.

The mighty oaks are also an ancient species, mentioned throughout human history in reference to their strength and endurance. Once an oak tree reaches a mature age, depending on the species, can live anywhere from 80 to 500 years.

The following are basic characteristics that can help you identify an oak tree:

  • Height: Oak trees generally grow to be 80 feet tall, but their height can range from 50 to 100 feet depending on the species. It can take 20-30 years for an oak tree to fully mature and reach its peak height.
  • Diameter: The average diameter of an oak tree is 4½ feet. Some oak trees can have a trunk diameter as large as 7 feet.
  • Leaves: The leaves of an oak will look different between different species, but they are almost always arranged in a spiral off the branch. Oak tree leaves can have serrated or smooth edges, and they can have thin elongated shapes, or lobe shapes more similar to that of a maple leaf.

Acorns from an oak tree in Chicago, Illinois

  • Flowers: Oak trees produce male and female flowers in the form of catkins, which are flower clusters with no pedals that are cylindrical in shape. The catkins of an oak tree are typically green or purple in color.
  • Fruit: The fruit produced by oak trees is the acorn. The acorn is a nut that contains one oak seed and it has a cup-shaped crown called a cupule. Acorns may look slightly different between species of oak trees.
  • Bark: The bark also looks different depending on the species of oak, but almost all oak trees have deep, defined ridges in the bark.

Oak Tree Sections

Oak trees are classified under the genus Quercus, and the different types of oak species under this genus are classified into 5 different sections; Quercus, Mesobalanus, Cerris, Protonalanus, and Lobatae. The following sections are those found in the United States:

  • Quercus: This section includes white oaks and other similar species native to North America, as well as Asia and Europe. Most oak tree species in the Chicago area fall under this section.
  • Protobalanus: This section includes the canyon live oak and similar species and are commonly found in the southwest U.S.
  • Lobatae: This section includes red oaks that are found in North and Central America, as well as northern regions of South America.

Hybridization

It is common for oak trees to be hybrids of two different species of oak from the same section. The Quercus oaks, including the white oak, swamp oak, and Chinkapin oak are the most likely species to be hybrids due to wind pollination. These oak species can be pollinated by different species of oak in the same section because they do not distinguish the difference in pollination. Hybridization among oaks can also result from ecological stress factors.

Native Illinois Oak Trees

Autumn colors on oak trees are a common sight in the Chicago, IL suburbs

As mentioned above, there are approximately 20 species of oak native to Illinois. The following are brief descriptions of several of the most common oak trees in the Chicago area:

  • White Oaks: The white oak is the state tree of Illinois and can be found in every county of the state. These oaks usually grow to be about 60 to 70 feet tall, but can be as tall as 100 feet, and their trunk diameter can be between 4 and 7 feet. The leaves of a white oak are lobed with rounded tips. The acorns are greenish in color with a hairy cap, and they are eaten by squirrels, birds, and other local wildlife. White oak bark has light ridges and is grayish in color.
  • Swamp White Oaks: Swamp white oaks grow between 50 and 60 feet tall and they have an irregularly shaped crown and slender trunk. Their leaves are lightly lobed and fuzzy on the underside and their acorns are dark brown and grow on fuzzy stalks.
  • Shingle Oak: Shingle oaks can grow between 65 and 80 feet tall and start out with a pyramidal crown that becomes more outstretched and rounded with age. The leaves of a shingle oak are slender with smooth edges and they can turn different colors in the fall from dark yellow to red. Its bark has small, yet prominent ridges. Shingle oaks used to be much more prominent in the Chicago region, but they have become scarce because they were once used heavily to build roofing and shingles, hence the name.
  • Red Oak: Red oak trees can grow up to 70 feet tall and they develop symmetrical crowns. They get their name from the reddish color that the leaves turn in the fall. The leaves of a red oak are lobed with pointy tips, and the acorns are reddish brown in color. The bark of a red oak has flat ridges that get longer and broader with age.

Threats to Oak Trees – Disease and Insects

The various species of oak trees are vulnerable to several different diseases and pests that can cause damage to the tree. The following are the main threats to oak trees:

Diseases

  • Sudden oak death: This disease is caused by a water mold and it is very deadly to oak trees. It causes bleeding sores in the tree bark called cankers and kills the foliage.
  • Oak wilt: This is another fungal disease that is especially deadly for red oaks. The foliage on infected trees will begin to discolor and eventually die off the tree.
  • If your oak tree has rot, don’t let it end like this picture. Call a professional arborist like Hendricksen Tree Care

    Powdery mildew: Yet another fungal disease that results in spots of white mildew on the affected leaves. The spots will continue to expand and spread throughout the tree.

  • Rot: It is common for wood in older oak trees to rot from the inside. Excessive rotting can make the tree dangerously unstable. Unfortunately, Oak trees inflicted with serious rot may need to be removed, especially if close to a residence.

Insects

  • Wood-boring insects: There are several types of wood-boring insects that literally eat away at the wood inside the tree. These insects can cause serious damage inside the tree before their presence is apparent.
  • Galls: Galls are abnormal growths on oak trees that are typically caused by a parasite such as an insect, mite, bacteria, or fungus. There are many different types of galls that can affect oak trees and they can be caused by moths, scale insects, and certain wasps.

Oak Tree Care – Plant an Oak Tree Today!

Plant a new oak tree in your Chicagoland yard this Spring, and be sure to put mulch around the base to help retain moisture

Providing the right care and maintenance for your oak trees can help prevent harmful diseases and insect infestations. Oak trees are fairly low maintenance, they just need plenty of space to grow and should be planted in an area with well-drained soil and plenty of sun light. The following tips will help you care for your oak trees:

  • Watering: Oak trees are resistant to dry conditions so it is not necessary to water them more than 2 or 3 times during the summer if conditions have been dry. When you do water your oak trees, you should water them gradually throughout the day until the surrounding soil is thoroughly soaked. Do not water an oak tree more than once per month.
  • Mulching: Putting mulch around the base of an oak tree will improve the aeration of the soil and help contain moisture and nutrients. The mulch should extend out 4 to 6 feet from the base and should be no more than 4 inches deep.
  • Fertilization: Oak trees should be fertilized early in the spring with nitrogen-based fertilizers to help with new growth. You can also fertilize oak trees in season if they are showing signs of a nutrient deficiency.
  • Pruning: Pruning oak trees is important to remove dead or dying branches and keep the canopy the right shape. Tree trimming, especially in larger oaks, is also a dangerous job that may be best handled by a professional arborist.

Professional Tree Service for your Oak Trees

Oak trees have been gracing the Chicago area with their beauty since before Chicago was established as a city. If you are considering planting a new tree on your property, planting an oak tree will provide added beauty and shade. However, it is important to make sure your oak trees receive proper care to live long, full lives. At Hendricksen Tree Care, our professional arborists can provide complete tree care services including fertilization, pruning, and treatment for insects and diseases to help your trees live and grow to their full potential. We are passionate about caring for the trees that are native to the Chicago area. We serve the northwest suburbs of Chicago, IL including Arlington Heights, Northbrook, Palatine, Park Ridge, and surrounding cities.

Texas Red Oak, Spanish Oak, Spotted Oak, Red Oak, Rock Oak
Quercus texana

Fagaceae

Texas Red Oak is a medium to small tree, rarely growing over 75 feet, but usually 30 to 50 feet, with spreading branches. It is found on alkaline limestone and neutral to slightly acid gravels and sands of north central and central Texas west to the Pecos River. Along the White Rock Escarpment through Dallas to San Antonio there are hybrids of Texas Red Oak and Shumard Red Oak, Q. shumardii – the pure Texas Red Oaks exist to the west. Texas Red Oak is smaller, more often multi-trunked, and more drought tolerant than Shumard Red Oak. The foliage turns bright shades of vivid red and orange in autumn. The bark is dark gray to black with platelike scales, although sometimes it is light gray and smooth.

Plant Habit or Use: medium tree

Exposure: sun

Flower Color: reddish-brown, catkins 1 to 3 1/2 in. long

Blooming Period: spring

Fruit Characteristics: acorns, reddish-brown

Height: to 75 ft.

Width: to 60 ft.

Plant Character: deciduous

Heat Tolerance: high

Water Requirements: low

Soil Requirements: alkaline adaptable

USDA Hardiness Zone: 8

Additional Comments: There is a close relationship between Texas Red Oak and Shumard Oak. This has caused many botanical classification problems. The two trees may be listed as two separate species in some manuals, while list Texas Red Oak as a variety of Shummard Oak.

Plant Database

Marcus, Joseph A.

Quercus buckleyi

Texas Red Oak, Buckley Oak, Texas Oak, Spanish Oak, Spotted Oak, Rock Oak

Synonym(s): Quercus texana

USDA Native Status: L48 (N)

Small to medium tree to 15 m (50 ft) tall. Bark dark gray, smoothish, furrowed into ridges on lower trunk and older branches. Twigs slender, grayish or brownish, glabrous, ending in a cluster of small egg-shaped grayish or brownish buds. Leaves alternate, elliptical or obovate, 6-12 cm (2.4-4.8 in) long and 5-10 cm (2-4 in) wide,deeply divided into 5-9 (usually 7) lobes which are usually broadest toward the tip and end in several bristle-tipped teeth, shiny dark green above, pale green with tufts of hairs in vein axils below, turning brown or red in fall. Fruits are acorns maturing in the second year, egg-shaped, 12-18 mm (0.5-0.7 in) long and 8-14 mm (0.3-0.6 in) wide with a more or less shallow cup covering 1/3-1/2.

This species was named for Samuel B. Buckley, botanist and state geologist of Texas. Quercus buckleyi leaves are similar to those of Q. texana, but the two species do not overlap in their distributions. This species should be considered a conservation concern. The largest known Buckley oak grows in Travis County, Texas.

From the Image Gallery

Plant Characteristics

Duration: Perennial
Habit: Tree
Root Type: Tap
Leaf Retention: Deciduous
Leaf Arrangement: Alternate
Leaf Complexity: Simple
Leaf Shape: Elliptic , Obovate
Leaf Venation: Pinnate
Leaf Margin: Lobed
Leaf Apex: Acuminate , Acute
Leaf Base: Truncate
Breeding System: Flowers Unisexual , Monoecious

Inflorescence: Catkin
Fruit Type: Nut
Size Notes: Height to 75 ft. Width to 60 ft.
Leaf: Glossy green above, light green to coppery-green below
Autumn Foliage: yes
Fruit: Acorns biennial; cup scales smooth to sparsely pubescent, inner surface smooth, covers 1/3-1/2 of nut; smooth or slightly pubescent, broadly ovoid nut, 3/4 inch (19 mm) long.
Size Class: 36-72 ft.

Bloom Information

Bloom Color: White , Green
Bloom Time: Mar , Apr , May , Jun

Distribution

USA: KS , OK , TX
Native Distribution: Native to an area from southcentral Texas to northcentral Oklahoma.
Native Habitat: Restricted habitat associated with limestone ridges, slopes and creek bottoms.

Growing Conditions

Water Use: Low
Light Requirement: Sun , Part Shade
Soil Moisture: Dry
Soil pH: Alkaline (pH>7.2)
CaCO3 Tolerance: High
Cold Tolerant: yes
Heat Tolerant: yes
Soil Description: Medium Loam, Clay Loam, Clay, Limestone-based
Conditions Comments: Q. buckleyi is more drought tolerant than the Shumard oak, but less hardy. This tree tolerates alkaline soil as well as neutral and slightly acidic soil. It is a super shade tree if you do not mind raking leaves in the fall. Red or yellow foliage in the fall.

Benefit

Use Ornamental: Fall conspicuous, Attractive, Color
Use Wildlife: Produces large numbers of acorns, which are valuable as food for wildlife.
Use Other: Texas oak is usually too small for sawlogs.
Warning: Leaves and acorns can be toxic to animals if eaten. Humans should generally avoid ingesting plants that are toxic to animals.
Interesting Foliage: yes
Deer Resistant: No

From the National Organizations Directory

According to the species list provided by Affiliate Organizations, this plant is on display at the following locations:
Lady Bird Johnson Wildflower Center – Austin, TX
Brackenridge Field Laboratory – Austin, TX
Patsy Glenn Refuge – Wimberley, TX
Nueces River Authority – Uvalde, TX
NPSOT – Fredericksburg Chapter – Fredericksburg, TX
Texas Master Naturalists – Lost Pines Chapter – Bastrop, TX
NPSOT – Austin Chapter – Austin, TX
Jacob’s Well Natural Area – Wimberley, TX
NPSOT – Williamson County Chapter – Georgetown, TX

Bibliography

Bibref 766 – Dale Groom’s Texas Gardening Guide (2002) Groom, D.
Bibref 1134 – Field Guide to Native Oak Species of Eastern North America (2003) Stein, John D. and Denise Binion
Bibref 355 – Landscaping with Native Plants of Texas and the Southwest (1991) Miller, G. O.
Bibref 354 – Native & Naturalized Woody Plants of Austin & the Hill Country (1981) Lynch, D.
Bibref 318 – Native Texas Plants: Landscaping Region by Region (2002) Wasowski, S. & A. Wasowski
Search More Titles in Bibliography

Additional resources

USDA: Find Quercus buckleyi in USDA Plants
FNA: Find Quercus buckleyi in the Flora of North America (if available)
Google: Search Google for Quercus buckleyi

Metadata

Record Modified: 2017-06-24
Research By: TWC Staff

Go back

Texas is famous for its oak trees. In fact, there are more than 50 varieties native to Texas. Oak trees are important for wildlife because they provide acorns for food, and the large trees provide shelter within their huge branches. Even after an oak tree dies in the wild, it provides shelter as it slowly decays. Some oak trees grow more quickly than others and make good trees for landscaping. These trees can also help decrease your utility bills, protect against erosion, add to your landscape’s aesthetic appeal, buffer your home from strong winds and add to the value of your home.

Oak Tree Leaves: Similarities And Differences

There are about 60 different types of oak trees which are native to North America. These trees fall into two primary categories: red oaks and white oaks. Oaks have what is called “alternate” leaves, which means that only one leaf emerges from the stem, which gives the appearance that the leaves are alternating from one side to another. Depending on the species, the leaves can be a different shape or have a different number or shaped “lobes”, which are the parts of the leaf which curve outward from the primary vein.

A post oak leaf is usually dark green, thick and leathery. These leaves usually measure between four and six inches and have five lobes. Live oak leaves look very different from post oak leaves, with an oval shape and a glossy surface which is usually between two and four inches long. Bur oaks have leaves that resemble post oaks. These leaves are up to a foot long with five to nine lobes. Red oaks have leaves which come to a point at the ends instead of the rounded tips of post oaks and live oaks. These trees have between seven and nine lobes. To identify other species which grow in Texas by the shape and size of the leaf, consult the Trees of Texas database.

Types of Oak Trees in Texas

Which varieties of oak trees grow best in Texas, and what are their characteristics? Read on to learn more.

Post Oak

The post oak (Quercus stellata) grows in most parts of Texas and is one of the most important oak trees for wildlife because of the large number of acorns it produces. This type of oak is so common that an entire ecoregion is named after it: Post Oak Savannah. Post oak trees are not adapted for landscape use because they are difficult to transplant and have a slow growth rate. They often die when the soil around their base is disturbed or compacted. Post oaks prefer dry, sandy soil. They shed their distinctive cross-shaped leaves in the fall, and the fall color is brown or red.

Post oaks thrive in Texas because they require little water and tolerate heat well. Mature trees can grow to a height of 50 feet or more, with a diameter of up to two feet. Since the tree’s root system is shallow, post oaks are sensitive to excessive watering and the impact caused by new construction. To protect these oaks in your landscape, avoid hardscaping near the boundary of the tree’s root system to minimize soil compaction. Do not remove or add dirt or other materials within the root system boundary. To avoid overwatering, check drainage in your yard to make sure the soil around the tree’s base doesn’t get too moist and to avoid tree rot. Resist the urge to mulch around the tree to curb water buildup.

Live Oak

Although the live oak (Quercus virginiana) only grows to 50 feet tall, it can spread out up to 100 feet with big limbs reaching the ground in all directions. The live oak owes its name to the fact that the tree is evergreen rather than deciduous, as most other oak species are. The limbs of a live oak are strong and thick, and the tree is one of the slower growing varieties of oak trees. Live oaks are long-lived trees. The oldest known specimen in Texas is in Goose Island State Park in Rockport and is more than 1,200 years old. The live oak is a semi-evergreen that sheds its leaves in late winter, but they are immediately replaced with new leaf growth.

Gardeners have long found it a challenge to add grass and other plants to a landscape with live oak trees, since the large, thick canopy makes for a shady understory. In addition, live oak roots and leaves produce a chemical which prevents plant growth nearby, thanks to an adaptation called allelopathy. Because they tend to require less water and are heat-tolerant, shade-tolerant native plants and shrubs are often the best additions to a landscape with a live oak. As with other species of oaks, live oak roots grow close to the surface, making them vulnerable to damage by root fungus diseases, trenching, digging, traffic and soil compaction. Pruning may become necessary if long, heavy limbs pose a risk of limb failure over time as the tree ages.

Bur Oak

The bur oak (Quercus macrocarpa), also known as the prairie oak, is known for its large leaves and big acorns. This species is native to grassland prairies of Central and West Texas but is adaptable to most areas of the state. It has a medium growth rate but becomes such a magnificent tree that it is worth the wait. Larger trees have a large tap root that makes it difficult to transplant, so when buying a bur oak tree for planting in the landscape, buy a tree that is three to five feet tall. The bur oak’s fall color is brown, and it sometimes holds its dried leaves well into the winter. The bur oak is very drought tolerant once it is established.

One of the advantages of adding a bur oak to your landscape is that it is one of the fastest-growing shade trees, growing at a rate of up to two or three feet a year under ideal conditions. In fact, bur oaks are the only other species, other than cottonwoods, which can grow to be up to 10o feet tall. Unlike live oaks, the deep tap root system of the bur oaks allow the species to draw water and anchor the tree, even in the driest conditions. One of the only disadvantages of the tree is its large size and its golf ball-sized acorns, which can get in the way if you are mowing your grass or which can even dent vehicles. Thankfully, bur oaks don’t produce many acorns, and resident wildlife will happily help get them out of your yard.

Shumard Red Oak

The Shumard red oak (Quercus shumardii), also known as the swamp red oak or spotted oak, can grow up to 120 feet tall and 50 feet wide in moist, well-drained soil. The tree is named after Benjamin Franklin Shumard, the state geologist of Texas during the late 1800s. Although it is adapted to the eastern third of Texas, this oak species can be planted in the alkaline soils of Central Texas if there is adequate moisture. One of the distinctive features of this oak species is its leaves, which turn a brilliant red and purple in the fall. The Shumard red oak is a medium- to fast-growing tree.

Similar to other oak species, the Shumard red oak is long-lived and drought tolerant. Unlike post oaks and live oaks, Shumard red oaks tolerate compacted soil and are often incorporated into urban landscapes and even on streets, since they can grow in areas with air pollution, poor drainage and drought. The only downside, as with other oak trees, is the inconvenience of dealing with the tree’s acorns.

Oak Wilt

One of the biggest threats to oak trees in Texas is oak wilt, an often deadly fungal disease which compromises the tree’s ability to retain water. Although all oaks are vulnerable to this pathogen, red oaks, including Texas oaks, Shumard oaks, blackjack oaks and water oaks are the most at risk. White oaks and live oaks are someone susceptible to oak wilt. Signs of oak wilt include leaves with yellow veins which eventually turn brown, otherwise known as veinal necrosis. Symptoms of oak wilt are harder to find, but can include the presence of fungal mats. To find these spore-producing structures, look for narrow cracks in a tree’s bark which lead to hollow areas between the bark and the wood. You may also detect a distinct odor emanating from the fungal mats which attracts many types of insects.

The best way to avoid the spread of oak wilt is by only pruning between the months of July and January. When trimming oak trees, treat freshly-cut wounds with any type of paint to prevent trees from being exposed to insect vectors. Immediately dispose of diseased tree material impacted by oak wilt to make sure the disease doesn’t spread to other trees on your property.

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Northern red oak (Quercus rubra)

Fruit

Propagation Method

Seed collection: Northern red oak fruit is a nut commonly called an acorn. They form along the branches. Harvest the fruit in the fall after the acorn becomes brown or tan. Seeds can be collected after they fall to the ground. The cup is usually removed from the acorn prior to storage or germination. It is common to find weevils in acorns and they can destroy the ability of the seed to germinate. You can determine if the acorns have weevils by placing them in water. Acorns that float usually contain weevil damage and should be discarded. Only save the acorns that sink. They can be stored for short periods (~ 1 year) in air tight containers in the refrigerator if the seeds are not permitted to dry out.

Seed dormancy: Northern red oak has physiological dormancy.

Seed germination: Stratify seeds using moist chilling for 60 days to satisfy physiological dormancy. Following stratification, sow seeds in a nursery container to produce a seedling or sow them in a plastic container in the classroom to observe germination.

Return to propagation selection page

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Yard and Garden: Handling, Germinating and Planting Acorns

AMES, Iowa – Fall is here, and so are acorns, falling from oak trees into yards everywhere. Viable acorns can be grown into oak trees, if properly handled. How is this done?

Here are some tips from Iowa State University Extension and Outreach horticulturists on how to best handle, germinate and plant acorns. To have additional questions answered, contact the ISU Hortline at 515-294-3108 or [email protected]

My oak tree produced just a few acorns this year. Why?

It’s common for the acorn crop on oak trees to vary from year to year. Most oak species produce a good crop of acorns once every two or three years. However, the white oak (Quercus alba) tends to produce a good acorn crop once every four to six years.

Weather and other factors can affect flowering and fruiting. For example, freezing temperatures in spring (when trees are flowering) can damage or destroy the flowers, drastically reducing the fruit crop.

The acorns of white oak, swamp white oak (Quercus bicolor), and bur oak (Quercus macrocarpa) mature in one year. Red oak (Quercus rubra) and pin oak (Quercus palustris) acorns mature in two years.

How do I germinate acorns?

Acorns should be collected as soon as they fall to the ground. Sound, viable acorns can be separated from damaged or unfilled acorns by placing them in water. Sound acorns sink. Most floating acorns are not viable and can be discarded.

The acorns of white oak and swamp white oak should be planted in fall. They will germinate immediately after sowing.

Acorns of bur oak , pin oak, and red oak will not germinate until they have been exposed to cool temperatures and moist conditions for several weeks. Winter weather in Iowa normally provides the necessary conditions to break dormancy. The cold-moist requirement can also be accomplished through a process called stratification. Acorns can be stratified by placing the seeds in a moist mixture of sand and peat moss and then storing them in a cool location.

Suitable containers include coffee cans, plastic buckets and food storage bags. The refrigerator is a good storage location. (Stratification temperatures should be 32 to 41 degrees Fahrenheit.) Acorns of the bur oak require a 30 to 60 day stratification period, while red and pin oak acorns require 30 to 45 days. Acorns of bur, pin and red oaks can be planted in fall or stratified seed can be sown in spring.

When planting acorns, place the seeds one-half to one inch deep. Choose a planting site where the oak seedlings can receive good care for one to two years before they are transplanted to their permanent locations.

To prevent squirrels and other animals from digging up and eating fall planted acorns, cover the area with chicken wire or hardware cloth fencing after planting. Promptly remove the fencing material in spring when the acorns begin to germinate.

There are small, round holes in many of the acorns on the ground. What made the holes?

The small, round holes on the sides of the acorns were likely caused by the larvae of the acorn weevil.

The adult acorn weevil is a brown beetle about three-eight inch in length and has a long, thin snout. Adult females lay their eggs inside developing acorns on trees in mid-summer. The eggs hatch into creamy white, grub-like larvae that feed inside the acorns until fall. In fall when the acorns have fallen to the ground, the fully grown grub chews a round one-eighth inch hole in the side of the acorn, exits the acorn and tunnels into the soil to complete its development.

Squirrels and other wildlife eat or stash away the good acorns, leaving the “holey” (destroyed) acorns on the ground.

Red Oak acorns have a shallow dormancy, if they are sown outside in late winter or early Spring the dormancy will be easily broken by the cold conditions naturally found within the soil. They can be sown outside in the garden usually during late February or March in soil that has been well cultivated and is free from weeds. Acorns can be broadcast over the soil or sown in drills and covered with a couple of centimeters of fine soil and will need protecting from mice, squirrels and pigeons etc. and intense frost
For seed that will be sown under glass the acorns should be mixed with a 50/50 blend of moist peat/compost and sharp sand -just enough to separate the seeds from each other. Put them in a plastic bag (freezer bags are ideal) and place the loosely tied bag in a fridge for at least 4 weeks. If they show signs of germination sow them immediately. After this period of pre-treatment they can be sown in good quality potting compost in deep containers (at least 20cm deep), covering each acorn with a couple of centimeters of soil
As soon as these seeds germinate they produce a very strong taproot, planting in shallow containers will cause severe root deformation. They can be started off under protection or indoors but should really be placed outside from the early summer. If you need to store your acorns before pre-treatment, mix them with slightly moist compost or peat and keep them in a cool place such as a frost free unheated outbuilding or in the fridge.
Initial growth is very rapid and within a few weeks from germination the seedlings will be between 10 and 20cm high. The trees will then rest for a few weeks before developing a terminal bud that will break into rapid new growth if the conditions are right. This usually brings height growth to 20 to 40cm. In warm locations and in favourable years the seedlings can even have a third growing phase of rapid growth before setting a resting winter bud. To encourage maximum growth ensure that the trees are never stressed because of a lack of water and that they are well nourished and grown in a warm, sunny position.
Trees should be planted in their permanent position as soon as is practical. If they are large enough, at the end of their first growing season and certainly at the end of the second. Allowing them to be grown in too shallow a container for any length of time will cause permanent root deformities that can lead to the failure of the tree once it grows to a large stature. Remember that Red Oak is pretty fast growing and will become very large and responds poorly to attempts to control its size by pruning.

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