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03/05/2020

Swamp White Oak

Swamp Oak

The Ohio Chapter ISA continued efforts is to advance responsible tree care practices through research, technology, and education while promoting the benefits of trees. This month Tree-Of-The-Month is commonly known as the Swamp White Oak(Quercus bicolor

The Swamp White Oak(Quercus bicolor) is an underutilized tree in the urban landscape today; however, for 1000’s of years in nature, it has tried and true record. If sited correctly, it could become an essential sustaining contributor to the urban forest canopy. This tree has a native range that starts from Ontario and to the Atlantic Ocean throughout the eastern seaboard states to South Carolina.  Its range reaches throughout the Midwest to the western states Missouri and Iowa. When you find this species of oak tree growing in natural conditions, it grows in groves of like species of Oak, Hickory, Elms, and other tree species

Swamp white oak is a large, full, round-topped, deciduous tree. Its leaves, with their silvery undersides, are similar to those of White oak (Quercus alba), yet Swamp white oak leaves lack deeply cut lobes. The tree grows to 100 feet (30.5 m) with an irregular crown. Bark dark gray, deep furrows are forming scaly or flat-ridges. Twigs smooth, light brown twigs; buds light orangish-brown, smooth, ovoid, and blunt. Leaves petiole from 3/8 - 1 inch (10 - 25 mm) long; leaves are narrowly elliptical to obovate, varies up to 7 inches (178 mm) long and 4 3/8 inches (111 mm) wide; base cuneate to acute, rounded apex; margin with 10 - 20 lobes with shallow sinuses, distal half of blade may have teeth; glossy dark green above with white velvety pubescence beneath. Fall color is golden-brown to russet-red.

One of these trees' greatest assets is its bright shiny leaves that make it a very handsome addition to the garden if it is given plenty of suns to grow.  This tree species is tolerant of partial shade conditions and is a beautiful tree to integrate when one is trying to create understory trees to replace a nearby declining tree.

Planting Requirements

Swamp White Oak can be grown and transplanted by nurseries by container production, balled and burlap, as well as bare-root methods. Unlike other Oaks, Swamp White can even be dug and harvested in the fall with a great deal of success in today’s urban landscape. Once established, this stress-tolerant species will grow rapidly with an average shoot elongation from 15-24” annually. 

If you are looking for a tree that can replace Ash trees or need a quick-growing shade-producing tree that will thrive in today’s urban conditions, then Swamp White Oak may be an excellent choice for your tree’s needs!

Swamp white oak grows in acid soils and is tolerant of high pH soils like what is found in new construction sites and can tolerate wet to arid soils.  This tree thrives in low oxygen soils that are heavily compacted, and its branches are unique with a central leader habit when it is young and will create a broad spreading tree that can reach 50-60 in height. Surprising Swamp White Oak has a cold tolerance to zone 4 and has the biological potential for at least 300 years.

Cultivars, Improved, and Selected Materials (and area of origin)

Swamp White Oak also has been known to hybridize with other nearby Oaks, and plant breeders often rely on Swamp White to create unique plant selections, and the following six hybrids with swamp white oak are recognized: Quercus x jackiana Schneid. (Q. bicolor x alba); Q. x humidicola Palmer (Q. bicolor x lyrata); Q. x schuettei Trel. (Q. bicolor x macrocarpa) ; Q. x introgressa P. M. Thomson (Q. bicolor x muehlenbergii x prinoides); Q. x substellata Trel. (Q. bicolor x stellata); Q. x nessiana Palmer (Q. bicolor x virginiana). Swamp white oak also hybridizes with chestnut oak (Quercus prinus) and English oak (Q. robur). Other named cultivars are:

National and Ohio champion trees

According to the website American Forrest, the national champion, Swamp White Oak, is located in Franklin Township, New Jersey, at is 97 feet tall and 101 feet wide. According to the Ohio Department of Natural Resources Division of Forestry says in Ohio, our state champion is located in Licking County and is 70 feet tall and 76 feet wide.

Unique Genetics

Two forms of swamp white oak have been described: a mesophytic form with leaves that are green and velvety on the lower surface and prefer soil conditions that provide moisture consistently like bogs and or swampy areas.

A second form is a xerophytic form with leaves that are white-tomentose beneath, and this plant species have evolved over time to adapt to dry regions.

Ethnobotany

Swamp White Oak falls into the white oak group and shares many of the same traits as White Oak (Quercus alba). White Oak, along with its brother Red Oak, are commonly used domestic lumber species. Hard, durable, and moderately priced, White Oak presents an exceptional value to woodworkers—which explains why it is so widely used in cabinet and furniture making. Swamp White acorns are noted to be some of the sweetest acorns of any of the oaks grown in the North American this species of tree is the food of choice squirrels. In a study in Wisconsin, swamp white oak acorns were found to make up 27 percent of the diet of wild ducks and other nongame bird species. It is also known Swamp White Oak provides habitat for songbirds, ground birds, water birds, and mammals.

Human Use-Food: Acorns (nuts) are edible after tannins are leached or boiled out. Gather nuts during the fall from September to October. Only gather the ripe tan-to-brown acorns, rather than the unripe green ones. To remove bitterness, shell the brown, ripe acorns and remove any corky skin layers, dice the meat, and boil the chunks in water from 15 to 30 minutes until the water turns brown. Then pour off the water and repeat the process until the water clears, indicating that the tannic acid has been removed. During the last boiling, salt water can be added; then, the acorns can be deep-fried or mixed in a soup. Finely chopped acorn meats can be added to bread doughs and muffin batters.

Use Medicinal: The Iroquois peoples used this oak as medicine.

Use Other: Swamp white oak produces a hardwood that has been used for construction, cabinet making, boat building, railroad ties, fencing, and cooperage.

Warning: Acorns (seeds of nuts) and young leaves. Low toxicity if eaten. Symptoms include stomach pain, constipation, and later bloody diarrhea, excessive thirst, and urination.

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Swamp Oak 2 Swamp Oak 7
Swamp Oak 5 Swamp Oak 6

Tree Selection Tips
The Ohio Chapter ISA recommends working with an ISA Certified Arborist when selecting or caring for any tree in your landscape. To better guide you on the vital plant information use our friendly users guide below:

Genus Quercus
Plant Family Fagaceae (Beech Family)
Life cycle Perennial woody
Origin Native to the United States
Habitat Full Sun
Tree form Large, wide, round-topped tree.  Unless a unique cultivar.
Does it produce shade? Yes
Soil

Soil Preference:  Poorly drained, heavy, or fine loams or clays.  
Tolerances:  Dry sites, Wet sites, Occasional flooding, Clay soil
Acid Soils:  Prefers
Alkaline Soils: Moderately Tolerant
Salt Spray: Tolerant
Soil Salt: Intolerant
Drought Conditions: Moderately Tolerant
Poor Drainage: Tolerant

Bloom season May and inconspicuous and not Showy.  Male catkins are 2-4 inches long.
Fruit/Seed Acorns annual; 1-2 acorns on peduncle up to 4 inches (101 mm) long; a grayish-green cup with scales covered with fine gray tomentum, cup rim often has spinose bristles, and cup covers 1/2 to 3/4 of the nut; oblong or ovoid, light brown nut, up to 1 1/4 inches
Plant height 72-100 ft.
Plant spread 50-80 feet
Growth rate Fast
Suitable for planting under or near electric(utility) wires No
Potential Concerns Anthracnose, occasional powdery mildew, chlorosis in high pH soils, and insect galls.  It is relatively resistant to oak wilt but may be affected by "oak decline;" anthracnose may sometimes be a problem.  SHOULD ONLY BE PRUNED IN WINTER.
Unique Traits This is one of the faster-growing oaks and appears to be more tolerant than similar trees to landscape use.  Swamp white is susceptible to iron chlorosis and prefers somewhat acidic soils.


Written by Mark A. Webber BCMA, CPH, LTE,  MArborA, OCMNT, TRAQ

 

Sources:

 

Robert Rogers. Swamp White Oak. USDA Silvicultural Manual  http://www.na.fs.fed.us/spfo/pubs/silvics_manual/volume_2/quercus/bicolor.htm

Bray, J. R., 1960. A note on hybridization between Quercus macrocarpa Michx. x Quercus bicolor Willd. In Wisconsin. Canadian Journal of Botany 38(5):701-704.

Field Guide to Native Oak Species of Eastern North America (2003) Stein, John D., and Denise Binion

Native Alternatives to Invasive Plants (2006) Burrell, C. C

Thomson, P. M., 1977. Quercus-Introgressa sexual hybrid, a new hybrid oak. Rhodora 79(819):453-464.

Clark, F. Bryan. 1965. Swamp white oak Quercus bicolor Willd.). In Silvics of forest trees of the United States. p. 625-627. H. A. Fowells, comp. U.S. Department of Agriculture, Agriculture Handbook 271. Washington, DC.

Martin, A. C., H. S. Zim, and A. L. Nelson. 1951. American wildlife and plants. McGraw-Hill, New York. 500 p.

http://www.boldspring.com/trees/qad-std (Collected on March 2, 2020)

https://www.mortonarb.org/trees-plants/tree-plant-descriptions/swamp-white-oak#destination (Collected on March 2, 2020)

https://www.wood-database.com/swamp-white-oak/ (Collected on March 2, 2020)

https://www.wildflower.org/plants/result.php?id_plant=qubi (Collected March 2, 2020)

 

Photograph sources Mark A. Webber 2020

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