Description & Overview

Members of the Quercus genus are at the pinnacle of wildlife value – Black Oak is no exception. This fellow Wisconsinite is commonly found growing in the Southeastern part of the state – naturally occurring in our upland woods, sandy woodlands, or sandy savannas. This oak is known for the charcoal to the brownish-gray color of its trunk. Black Oak can be distinguished from other oaks by the patches of tan to reddish-brown hairs on the foliage’s undersides.

Core Characteristics

Category: Tree

Wisconsin Native: Yes

USDA Hardiness Zone: to zone 4

Mature Height: 50-60 feet

Mature Spread: 50-60 feet

Growth Rate: Very Slow

Growth Form: Upright, Rounded.

Light Requirements: Full Sun

Site Requirements: Dry, sandy soils to rich, silty soils. Intolerant of alkalinity

Flower: Inconspicuous, yellowish-green catkins

Bloom Period: April to May

Foliage: Thick, glossy green. Pale green underbelly

Fall Color: Dull Red, Yellow-bronze

Urban Approved: No

Fruit Notes: Elliptic acorn (3/4" long) with a saucer-shaped cupule.

Suggested Uses

Black Oak is an excellent choice as a shade tree or specimen so long as there is plenty of room for it to reach its mature size. While this species may develop chlorosis in alkaline soil, we select our Black Oaks to have a higher-than-average tolerance to soils with higher pH. Black Oak is adaptable and can tolerate poor, dry sites, and even those plagued with heavy clay.

Once established, Quercus velutina is exceptionally tolerant of sandy sites and drought, making it particularly useful in native restoration projects in dryer, sand-filled soils.

Black Oak is not extensively planted as an ornamental, but its fall color greatly contributes to the aesthetic value of oak forests.

Black Oak has similar foliage characteristics and acorns to Hills Oak (Quercus ellipsoidalis) and can readily hybridize. It’s challenging to tell the difference between Black Oak and a Hills Oak in the wild. A characteristic that we have observed that helps determine the difference between the two species is the fuzz on the dormant buds. Black Oak has fuzz, while Hills Oak does not. So, if you are in the sand country of Wisconsin and are wondering what oaks you are looking at, you should pull over and look at the buds!

Members of the Quercus genus are at the pinnacle of wildlife value – Black Oak is no exception. This fellow Wisconsinite is commonly found growing in …
Members of the Quercus genus are at the pinnacle of wildlife value – Black Oak is no exception. This fellow Wisconsinite is commonly found growing in …
Members of the Quercus genus are at the pinnacle of wildlife value – Black Oak is no exception. This fellow Wisconsinite is commonly found growing in …

Wildlife Value

Like other members of Quercus, Black Oak has an exceptionally high ecological benefit.

Black Oak is a member of the Red Oak group – meaning there is a higher tannin content in their acorns, making them more bitter tasting than those of the White Oak group. The acorns are produced more frequently and consistently than the White Oak group oaks, so it’s still an important food source for wildlife. Many mammalian and avian foragers like white-tailed deer, wood ducks, turkey, squirrel, chipmunk, raccoon, and black bears love feeding on acorns. Check out our Oak Comparison resource to see the difference between the Red and White Oak groups.

The foliage is eaten by the caterpillars of several butterfly and moth species such as Hairstreaks, Duskywings, Sphinx Moth, Great Oak Dagger Moth, and Sallow Moths. Other leaf-feeding insects include Oak Lace bugs, leafminers, aphids, and leafhoppers. The many insects that feed on oaks attract many insectivorous birds such as blue jays, woodpeckers, and warblers. Many birds favor oak trees for nesting habitats and feeding sites.

It should be noted that Black Oaks – and other oaks in the Red Oak group – tend to have higher concentrations of phenolic compounds and hydrolyzable tannins than other oak species, which are toxic to horses. Horses must consume large quantities over several days to develop oak toxicity – an illness predominately characterized as a gastrointestinal disease. Horses are most at risk of oak toxicity when turned out in pastures with little grass and access to fallen acorns. Black Oak was found to have the highest level of total phenolics.

Maintenance Tips

Black Oak typically grows in upland woods, sandstone glades, limestone glades, sandy woodlands, savannahs, and even stabilized sand dunes. This oak performs best in full sun in well-draining soil with dry to average moisture conditions, although it is often found on poor, dry, sandy, or heavy glacial clay hillsides.

All oaks are susceptible to the Two-Lined Chestnut Borer during their establishment period after planting. We recommend applying a systemic insecticide containing imidacloprid to Black Oaks when planting to protect against this insect. Be sure to give your oak a generous mulch ring and plenty of water to ensure it gets established quickly.

Do not prune Black Oaks during the growing season. Like all oaks in the Red Oak group, Black Oaks are highly susceptible to Oak Wilt, which is spread by a sap beetle that is attracted to fresh wounds. Prune oaks only during the dormant season in winter after the leaves have fallen. Oak Wilt can kill a Black Oak within one season if the tree is stressed, and it’s always fatal to trees in the Red Oak group.

We invite you to check out the Arborist For Hire lookup at the Wisconsin Arborist Association website to find an ISA Certified Arborist near you.

Members of the Quercus genus are at the pinnacle of wildlife value – Black Oak is no exception. This fellow Wisconsinite is commonly found growing in …
Members of the Quercus genus are at the pinnacle of wildlife value – Black Oak is no exception. This fellow Wisconsinite is commonly found growing in …

Pests/Problems

Oak Wilt is the primary disease to concern yourself with for Black Oak. This fungus will spread through root grafts between trees and kill entire stands in a forest setting. In a landscape setting, Oak Wilt is easy to avoid. Pruning should be postponed to the dormant season when the sap beetles are not active. Oak Wilt is always fatal to oaks in the Red Oak group. Oak Wilt cannot be treated once the tree is infected. Consult an ISA-certified arborist if you think your tree might be afflicted.

The Two-Lined Chestnut Borer is an insect you should be aware of when planting oak trees. The insect will attack stressed trees, especially newly transplanted individuals. We recommend applying a systemic insecticide containing imidacloprid for the first two years after planting to ensure your oak is protected from this insect. In addition, make sure the trees are given a generous mulch ring and watered regularly to get established quickly. The faster your oak gets established, the quicker the two-lined chestnut borer will lose interest and find them unattractive. Once they are established, treatments are no longer necessary, and they are on their way to becoming beautiful trees.

Leaf Lore

Quercus velutina is a member of the Beech (Fagaceae) family. The specific epithet ‘velutina’ is the Latin word for “velvety” in reference to the underside of the leaves, which are covered with fine hairs. These fine hairs can also be found on dormant buds.

The national champion Black Oak made its debut in 2018 and was recognized as the largest known tree of its species. It stands at 78′ tall with a crown spread of 89′ and is located in Hartford, Connecticut.

Like other oaks, the heavy wood of Black Oak is often used to make furniture, floors, interior finishing, barrels, railroad ties, and other products.

Companion Plants

Common forest companions include:

Other non-tree, sand-loving (or sand-tolerant) plants you may find growing near Black Oak are:

Members of the Quercus genus are at the pinnacle of wildlife value – Black Oak is no exception. This fellow Wisconsinite is commonly found growing in …
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Written by Miles Minter