Complete Guide For Swamp White Oak Tree – What You Need To Know


One of the more common Oak trees you may encounter near water is known as Swamp White Oak. Although moisture loving, it is really quite adaptable in regards to what growing conditions it can tolerate. I’ve grown to love this member of the White Oak family for it’s shape, wildlife value, and ease of germinating the acorns.

In this article:

What is Swamp White Oak

Swamp White Oak is a long-lived medium-sized deciduous tree native to North America.  Scientifically known as Quercus bicolor, it reaches heights of 60-80’ in full sun and wet or medium moist soil.  As a member of the White Oak family, it is hugely important for wildlife supporting dozens of species of butterfly, moth, leafhopper, and beetles. [1][2][3][4]

But the value doesn’t stop with insects, as Swamp White Oak is a keystone species.  While birds eat the caterpillars on the leaves, other birds such as Blue Jays or Turkey eat the acorns, often competing with mice, deer, squirrels, and chipmunks for the nuts. And finally, deer will browse saplings and rabbits will chew young bark in particularly cold Winters.

As the common name would imply, Swamp White Oak grows in moist areas and near bodies of water. Lumber from Swamp White Oak is prized for it’s strength, rot-resistance, and hardness.  It has been used as kitchen cabinets, flooring, boat hulls, and even fence posts.

Native Range of Swamp White Oak

The native Range of Swamp White oak is primarily from Minneapolis ,South to Missouri near Kansas City, then East to the Atlantic Ocean.  Isolated populations exist in Southern Quebec, Virginia, Tennessee, and North Carolina.

Sources [1][3]

The natural habitat of Swamp White Oak is the edges of ponds, lakes, within river or stream valleys, sloughs, and low-lying fields.  It can also grow in deciduous forests with medium moisture.  But being near water is definitely it’s natural habitat. 

However, it won’t tolerate permanent flooding.  So, you can keep it near a lake, but not in it.

Swamp White Oak Reference Table

Scientific NameQuercus bicolor
Common Name(s)Swamp White Oak, Swamp Oak
Native Range, USDA ZoneEastern United States, USDA Hardiness zones 3-8
Bloom Time, ColorSpring, Yellow
Growth Rate12-24″ per year (30-60 cm)
Height60′
Spacing / Spread50-60′
Light RequirementsFull sun to partial shade
Soil TypesSandy loam to clay loam
MoistureWet to medium moisture
Fauna Associations / Larval HostsAttracts much wildlife. Hosts numerous caterpillars.
Sources [1][2][3][4][5]

What are the Benefits of Swamp White Oak

Wildlife

Swamp White Oak trees are hugely important to wildlife.  Dozens of species of butterfly, moth, beetle, and other insect lay their eggs exclusively on Oaks (which includes Swamp White Oak).  These caterpillars feed numerous baby birds, which in turn are part of the greater food chain.  The acorns produced in Autumn are heavily consumed by many birds, ducks, and other animals such as bears, deer, raccoon, squirrel, and chipmunk. [3][4][5]

A house wren with caterpillar in it’s mouth.

Shade

Swamp White Oak reaches tall heights and can provide shade.  It grows relatively fast too, meaning it can reach a nice shade-providing height in roughly 20 years.[3]

Mature Swamp White Oak tree

Wet soil

Wet soil can often hamper our choices of trees to plant, as many species just can’t tolerate much flooding or wet feet.  Swamp White Oak will thrive in these conditions though, and research has shown that flooding doesn’t effect radial growth as much as other trees. [6]

Long lived

Swamp White Oak trees can live to be 300 years old, meaning the tree you plant today can be enjoyed for generations. [3]

Identification and Characteristics of Swamp White Oak

Swamp White Oak Growth Rate

Swamp White Oak grows fast, keeping pace with many other ‘fast growing trees’.  It has been documented to be over 30’ tall in 14 years when planted from bare root, which is a growth rate of over 2’ per year.[3]

The more sun provided, the faster Swamp White Oak will grow.

Trunk

In general Swamp White Oak will grow up to 60-80’ tall and develop an ovoid to obovoid crown.  However some specimens of 100’ and 84” d.b.h. have been reported in the past, particularly in Western New York.  At maturity the trunk can be 2-3.5’ diameter. [3]

When grown in the forest, the trunk is generally straight.  In the open, depending on available lighting, the trunk may be crooked if it was ‘reaching’ for sunlight.

Bark

The bark of Swamp White Oak changes with age.  It can be brown to gray, rough textured with furrows or flat-ridges.

Bark of a Swamp White Oak tree

Younger developing bark is generally brown and much smoother.  It will often have lenticels, which are small white dots.

Branching

The branch structure of Swamp White Oak will vary depending on the environment in which it grows.  When grown in forest stands, Swamp White Oak will have ascending branches and a narrow crown.  When grown in more open areas, the branching is generally irregular and will include many lower branches.

Leaf

The leaves of Swamp White Oak are arranged alternately.  They are usually 4-7” long by 2-5” wide, obovate or elliptic in shape, with 4-8 pairs of lobes on the edges.  The edges of the lobes will be rounded or blunted. [2]

Leaves of a Swamp White Oak tree

The upper surface of the leaves are medium green and smooth, while the underside is a lighter shade of green and will be covered with short white hairs.  The leaves feel very tough and somewhat leathery, and are attached with stems (petioles) that around ½”-1” long. In Autumn the leaves will turn mostly brown-yellow.  But sometimes you get shades of other colors too such as orange or red.

Fall Color of a Swamp White Oak tree

Flower

Swamp White Oak is either male or female.  The male flowers are drooping catkins (like a string with flowers attached) that are roughly 2-4” long.  While female flowers will be produced from the base of leaf stems in clusters of 2-4.[2]

Acorns

Swamp White Oak produce large crops of acorns every three to five years.  Acorns are usually in pairs, are ovoid in shape and rather large at roughly ¾” to 1-1/4” long and ½”-3/4” diameter.  They will generally fall in late Summer to early Fall, September to October.  Once they begin falling, you must be quick to collect them as the birds, rodents, and deer all prefer them as choice food. [2]

Swamp White Oak acorn

Two key features of Swamp White Oak acorns are that they are attached with long stems, and their crowns have a fairly unique look. I think the crown almost looks like a wig of hair rather than a ‘hat’. Just my personal opinion, but it gives them quite a distinct look.

How long until Swamp White Oak produces Acorns?

The earliest a Swamp White Oak will produce Acorns is 20 years of age, and the optimum producing age is from 75-200 years. [3]

Root

The root system of Swamp White Oak trees is shallow to medium depth, and very wide spreading.  It is very likely that the wetter the soil the more shallow the roots. [3]

Grow and Care for Swamp White Oak

Sunlight Requirements

Swamp White Oak prefers full sun, which is at least six hours of direct sunlight per day.  It can be somewhat tolerant of partial shade when a seedling or juvenile.  But eventually it will need the sun to fully mature.

Soil texture requirements

Swamp White Oak is tolerant of moist soil textures, from sandy soil to clay.  It can even handle compacted soil well. 

Moisture Requirements

For moisture, Swamp White Oak prefers wet to medium-moist soil.  It is not that drought tolerant. 

Maintenance

Swamp White Oak will need to be pruned periodically.  In late Winter trees should be pruned to ensure only strong branches are on the tree.  Any time a dead or dying branch is noted, it should be removed.

Fertilizer

Swamp White Oak should not require supplemental fertilizer.

How to Grow Swamp White Oak from Seed / Acorn

Swamp White Oak is relatively easy to grow from seed.  As a member of the White Oak family the acorns have no dormancy period.  So, they will germinate shortly after hitting the soil. [7]

Collecting / Harvesting Swamp White Oak Acorns

As soon as acorns are ripening, they will begin to fall off the tree.  This usually occurs in early Fall around September or October.  My advice to you is to locate your trees in late Summer, then watch them for any signs of dropping acorns.  Now, don’t be fooled by storms knocking off acorns prematurely.  You want to see/hear them falling every few minutes, or see fresh ripe acorns on the ground.

Swamp White Oak acorns.

Acorns that are still green in color are not mature, and should not be collected. 

Not ripe!

Examine the acorn for insect damage

If it is possible for you to collect acorns from the tree branches directly, you should do so, as this eliminates the possibility of insect damage.  But acorns that are collect from the ground should have their caps removed and then inspect the entire acorn for any holes.  And, any acorn that has a hole in it should be discarded as it is likely that it has a weevil or some other insect that has bored into the nut, rendering the acorn non-viable.

Float test

After inspecting acorns for insect damage, we need to conduct the float test.  Place all of your acorns into a bowl of water for sixty seconds.  Any acorn that floats is likely filled with air and should be considered non-viable, and discarded.  Acorns that sink within 60 seconds should be considered good, and can be planted. [8]

For more information on the float test and how accurate it is – see our write up here.

Storing Swamp White Oak acorns

Swamp White Acorns can be stored for a time if they are patted dry and placed in a sealed container or bag, in the refrigerators.  They can be stored in this manner for 3-6 months.  But know that the longer they are stored the lower the germination rate will be.

How to plant Swamp White Oak Acorns

Like all members of the White Oak family, Swamp White Oak acorns will germinate after being placed in a moist environment for a couple of days.  This is a great way to ‘test’ the viability and ensure you are only planting healthy acorns.

You can wrap them in a moist paper towel and keep them in a covered container for a day or two, checking them every 12 -24 hours.  Alternatively you can you can do this same test in moist sand, or moist soil by just pressing the acorns half-way in on their side.  Usually sprouting occurs in 1-2 days at room temperature, and within several days in the fridge.

Any acorn that sprouts can (and should) be planted 1-” deep in a pot containing moist potting soil immediately.  The pot can then be over-wintered in an unheated garage or shed, so long as the pot doesn’t freeze solid. Also, make sure the potting soil never fully dries out though.

Germination

Swamp White Oak acorns germinate hypogealy, so you won’t see any stems or true leaves until Spring. But, once temperatures are reliably approaching 70F, you should start to notice stems emerging. By mid to late May (zone 6) they should all have true leaves.

Swamp White Oak seedlings I grew in 2022.

Can you leave the pot with acorns outside?

Theoretically you can overwinter the pots outside, provided the acorn doesn’t freeze solid.  You see, and acorn nut is like a living thing, and if it freeze solid for an extended period of time, it will die.  I learned this the hard way the first time I sowed acorns.  So, learn from my mistakes!

Direct Sowing Swamp White Oak Acorns

Swamp White Oak Acorns can also be directly sowed in Fall.  If you wish to sprout test them to ensure they are viable, you can do so.  But then simply plant them about 1-2” deep in the ground, and cover them with chicken wire, hardware cloth, or some barrier to ensure squirrels and chipmunks don’t dig them up!

Caring for Swamp White Oak seedlings

Swamp White Oak seedlings will emerge in Spring.  They germinate hypogeal, meaning the cotyledon leaves are actually inside the nut, so you won’t see anything above the soil until well after the root is established.

But once it emerges, you can wait for it’s first leaves to show, then transplant it to it’s final location.  The earlier start the plant gets, the better.  You can however leave it in a pot over the first growing season, then plant it in it’s final location in Autumn.

Swamp White Oak seedlings are browsed by deer, and it should thus be protected with either a plastic tree shelter or cage.   Please consider doing this, as the threat posed by deer or even rabbits in Winter is quite real.

Should you apply mulch?

Swamp White Oak trees should not have mulch around their trunks. In particular, one should avoid the ‘mulch volcano’. Swamp White Oaks trees that have their root collars buried (either by mulch or too deep planting) can be susceptible to root rot, which can be fatal to the tree.[9]

Propagating Swamp White Oak via cuttings

Swamp White Oak can also be propagated by cuttings. Increased success is reported to occur as the younger the shoots, and the less light received.[10]

Wildlife, Pests, and Diseases associated with Swamp White Oak

Pollinators

Swamp White Oak is extremely valuable to pollinators not from it’s flowers, but from it’s leaves.  Dozens and dozens of butterfly, moth, beetle, and insect lay their eggs on this tree, and their leaves support the baby caterpillars.  Oaks in general are considered a ‘keystone’ species by Doug Tallamy due to their hosting ability. [4][5]

But that is not all, the caterpillars and bugs on an Oak tree are responsible for feeding numerous baby birds during the brooding season.  And these birds are themselves part of the larger food chain. [11][12]

Birds

Numerous birds love depend on Swamp White Oak to provide nourishing caterpillars for their young.[4][11][12]  But there are also numerous species of bird that feed on the acorns.  Blue jays, Blackbirds, Grackles, Grouse, Nuthatch, Pheasant, Brown Thrasher, Red-headed & Red-bellied Woodpeckers, and Turkey are just some of the birds who eat the acorns.  Amazingly, Wood Ducks & other ducks also enjoy the acorns, perhaps since they are usually close to water.  One study found that Swamp White Oak acorns could make up 27% of a duck’s diet.[3]

House Wren feeding a caterpillar to a baby that fledged the following day.

Other mammals

Other animals enjoy Swamp White Oak acorns.  Black bear, chipmunks, Raccoons, squirrels, and White-tailed deer also eat the acorns.

Deer and Rabbits

Like other Oak trees, Swamp White Oak seedlings, saplings, and new tender growth will be browsed by deer.[3][13]  They absolutely should be protected with a cage or tree shelter.

In winter, when there is a thick layer of snow on the ground for a prolonged period of time, rabbits may chew on the bark of young Swamp White Oaks.  This can be very damaging, and using a simple cage is often all it takes to dissuade them.

Disease

Similar to other members of the Quercus genus, Swamp White Oak is susceptible to cankers, fungi, and various insect pests. However, none generally warrant intervention, and usually survive without treatment. It is possible for it to get Oak Wilt, but is reported to be resistant especially compared with other Oak species.[2]

Where you can buy Swamp White Oak

Swamp White Oak is sometimes available from general garden centers, but often it is better to purchase from a nursery that specializes in trees or native plants. You can find native plant nurseries near you on our interactive map.

Uses of Swamp White Oak

Landscaping Uses

Swamp White Oak can be an excellent choice for landscaping near water or areas that occasionally flood.  Although not the fastest growers, they more than make up for it by the wildlife they support.  Once established they can make a nice shape and be an attractive landscaping tree. And Swamp White Oak is frequently encountered in municipal parks, golf courses, and other naturalized areas. [13]

Swamp White Oak in Winter

Shade tree / street tree

Another use of Swamp White Oak is as a shade tree or street tree. Because it is adaptable for growing conditions, Swamp White Oak can be utilized as a street tree.[2][14]

Companion Plants

Swamp White Oak is commonly found growing near other deciduous trees that are moisture loving and can tolerate occasional flooding.  Some examples would include Black Walnut, Butternut, Cottonwood, Shagbark Hickory, Black Willow, Basswood, Red Maple, Silver Maple, Sweetgum, and Sycamore.

For shrubs, Spicebush makes an obvious choice as it loves moisture and tolerates similar climate conditions.  Certain types of Viburnum can grow well too as long as the soil drains well. For flowers, a variety of Spring Ephemerals grow well near Swamp White Oak.  Marsh Marigold, Rue-Anemone, Spring-Beauty, Wild Violets all would do well.  For later season flowers, again we must try species that are somewhat shade tolerant and don’t mind moist soil.  The Great Blue Lobelia, Cardinal Flower, Wingstem, or Garden Phlox all can be found in similar conditions.

Wood uses / lumber

Swamp White Oak is a heavy, strong, dense, and hard wood.  It generally is fine-grained, and has a light brown color, and is sold as ‘white oak’ in lumber mills.  It has bee used for furniture, cabinetry, floors, barrels, and boxes/crates.  It is very rot resistant, and has also been used as boat hulls and even fence posts. [3]

The only downside of Swamp White Oak is that it does tend to be a bit knotty since it often is grown near water, leading to more branches. The ‘knots’ are often encountered as Swamp White Oak often grows near water, leaving at least one side exposed. If the trunk of a tree is exposed to sun, branches will form to create leaves so that photosynthesis can occur. This is in contrast to other Oaks in forest, where the only light is overhead, and thus there are fewer branches.

Leaves

It may be folklore, but leaves of Swamp White Oak reportedly repel various garden pests. It has been reported that they can keep slugs & grubs.[2] Also, the leaves of Swamp White Oak are good at suppressing Japanese Stilt Grass and generally persist well into Summer on the ground.[12]

Medicinal Uses

Swamp White Oak has been used medicinally by several different Native American Tribes. [2][15]

  • A decoction of bark was used to treat broken bones, cholera, and consumption
  • Bark was boiled with soft maple and hemlock bark as a cleaning agent to remove rust.
  • Leaves were smoked and exhaled through the nose for catarrh
  • Acorns were used for food

Final Thoughts

Swamp White Oak is a keystone species whose value to wildlife cannot be understated.  It hosts dozens of insects, feeds many birds and mammals, and the foliage is also browsed by deer.  It is a fast-growing Oak with some niche growing conditions that can add value in terms of being a shade tree and be aesthetically pleasing.  These reasons alone should justify more homeowners to consider landscaping with Swamp White Oak, as there really are no downsides.

Find more native plants here

References:

[1] – Quercus Bicolor. USDA NRCS. Accessed 10MAY2023.

[2] – M. Kat Anderson. “SWAMP WHITE OAK Quercus bicolor Willd.” USDA, NRCS, Plant Guide, National Plant Data Center, 2003. Accessed 10MAY2023

[3] – Rogers, Robert. “Quercus bicolor Willd.—Swamp white oak.” Silvics of North America 2 (1990): 614-624. Accessed 12MAY2023.

[4] – Narango, Desiree L., Douglas W. Tallamy, and Kimberley J. Shropshire. “Few keystone plant genera support the majority of Lepidoptera species.” Nature Communications 11.1 (2020): 1-8.

[5] – Tallamy, Douglas W., and Kimberley J. Shropshire. “Ranking lepidopteran use of native versus introduced plants.” Conservation Biology 23.4 (2009): 941-947. Retrieved 25MAY2023

[6] – Mitsch, William J., and William G. Rust. “Tree growth responses to flooding in a bottomland forest in northeastern Illinois.” Forest Science 30.2 (1984): 499-510.

[7] – Fare, Donna C. “Propagation container and timing of propagation affects growth of oak seedlings.” Journal of Environmental Horticulture 31.1 (2013): 43-48.Accessed 20MAY2023.

[8] – Gribko, Linda S., and William E. Jones. “Test of the float method of assessing northern red oak acorn condition.” Tree Planters Notes 46 (1995): 143-147. Accessed 20MAY2023.

[9] – Smiley, E. Thomas, Bruce R. Fraedrich, and Thomas R. Martin. “Phytophthoru Root Rot and Collur Rot of Landscupe Plunts.” (1999). Accessed 18MAY2023

[10] – Amissah, J. Naalamle, and Nina Bassuk. “Effect of light and cutting age on rooting in Quercus bicolor, Quercus robur and Quercus macrocarpa cuttings.” Combined Proceedings of the International Plant Propagators Society. Vol. 57. 2007. Accessed 20MAY2023

[11] – Tallamy, Douglas W., and Kimberley J. Shropshire. “Ranking lepidopteran use of native versus introduced plants.” Conservation Biology 23.4 (2009): 941-947. Retrieved 25MAY2023

[12] – Tallamy, Douglas W. The nature of Oaks: the rich ecology of our most essential native trees. Timber Press, 2021.

[13] – Grossman, B. C., M. A. Gold, and Daniel C. Dey. “Restoration of hard mast species for wildlife in Missouri using precocious flowering oak in the Missouri River floodplain, USA.” Agroforestry Systems 59 (2003): 3-10.

[14] – Brewer, Laura. “TABLE A. ACCEPTABLE SHADE OR CANOPY TREE SPECIES-DO NOT.” (2020). Accessed 24MAY2023

[15] – Quercus bicolor, North American Ethnobotany Database. Accessed 24MAY2023.

Joe Foster

Hi - I grew up outdoors in nature - hiking, fishing, hunting. In high school I got my first job at a garden center where I learned to garden and landscape. I've been growing plants from seed and designing native plant gardens for over 10 years. I hope to share some of my knowledge with you! You may have seen some of my videos I create on our YouTube channel, GrowitBuildit (more than 10 million views!). You can find my channel here: https://youtube.com/@growitbuildit Additionally I am a wood worker / DIY enthusiast. I enjoy designing/building projects (with hand tools when I can!). I hope to give you some tips and useful information!

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