King of the eastern North American forests, the northern red oak, Quercus rubra, can be found in woodlands all the way from Quebec to Georgia.
Growing up to 75 feet tall and just as wide, this prodigious acorn producer is an important player in the forest food web, feeding everything from weevils and mice to bears.
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Belonging to the Fagaceae family, which also includes chestnuts and beeches, red oak has many cousins you may be familiar with, including white (Q. alba), scarlet (Q. coccinea), and pin oak (Q. palustris).
Like all species in the Quercus genus, Q. rubra produces yellow male catkins, which are long and dangly. The small, inconspicuous female flowers are found on the same tree.
Hardy in USDA Zones 4 to 8, Q. rubra is one of the most rugged of the oaks. It’s tolerant of a variety of soil types, has relatively low water needs, and is largely pest and disease free.
Read on for more specifics about growing the mighty red oak. Here’s what I’ll cover:
What You’ll Learn
What Are Red Oaks?
“Red oak” refers primarily to two different species, as well as being the common name for the Erythrobalanus group – one of the two major groups that Quercus species are divided into.
Species in the Erythrobalanus group sport bristles or points at the ends of their leaf lobes and produce acorns which mature over the course of two years.
The northern red oak, Q. rubra, can be distinguished from the other species in the red oak group by its sharply pointed leaves and lobes that aren’t too deeply divided. In the fall, its leaves turn a beautiful deep reddish-bronze color.
The southern red oak, Q. falcata, is, as its name suggests, more southern in its native range. Its leaves are very hairy on the undersides and have numerous bristle tipped lobes.
Cultivation and History
Oak trees have a long and storied history. Q. rubra, as a North American species, was once a critical food source for Native American tribes who pounded the nuts to make a kind of meal, or flour.
The timber from these trees is prized for its durability and reddish tint, and is still used for furniture making, cabinetry, and as flooring.
Living up to the grand old age of 200 years, red oaks are what’s known as a climax species in the eastern forests. Essentially, this means they are dominant, abundant, and stick around for a long time.
This makes them of great ecological importance to forest ecosystems, providing food and shelter to a lot of wildlife.
In good acorn years, they produce thousands of pounds of nuts, and almost all of that crop is eaten by bluejays, bear, moose, and an abundance of other wildlife. A single turkey can eat over 200 acorns in a single meal!
It’s long been recognized that this species is tough, beautiful and easy to grow, too. Q. rubra has been in cultivation for almost three hundred years as a popular specimen and shade tree.
To find out how to grow your own red oak, keep reading.
Red Oak Propagation
Q. rubra can be grown from a purchased sapling or a lowly little acorn with relative ease.
For comprehensive details about how to start acorns indoors for transplanting, check out our guide to growing oaks.
The best time to plant acorns is in fall, shortly after they’ve fallen from the tree. Planting outside ensures each acorn receives the blast of winter weather they need to germinate.
To collect acorns, start searching as soon as they begin to drop from the branches. Usually this is around the end of September.
Collect only those that do not still have their “caps” on, and those that are free from obvious damage like holes or black stains. Place your bounty in a bowl of water and remove any that float as these are damaged or dead and will not germinate.
Once you’ve gathered 10 to 12 viable acorns, plant them directly in a prepared space in the garden about two inches deep.
Burying each seed a full two inches underground helps to prevent critters from finding your babies and digging them up.
Place stakes in the ground to remind you where you planted and a ring of chicken wire, or some other fencing to keep rabbits and groundhogs out.
Seedlings emerge in spring and need a lot of weeding. In its first tender year a seedling can be easily overrun by grass and other weeds.
Make sure to clear a circle of ground around your baby tree so it doesn’t have to compete for light or nutrients.
Also, oaks are a favorite of deer. Place a tree tube around the young specimen until it gets above deer height, about four to five feet.
This could take a few years. I prefer mesh tubes as they don’t get super hot inside during summer. You can purchase these on Amazon.
Depending on the size you choose, young trees will come either in containers or in a wrapped burlap ball. Make sure when transplanting your specimen you pay particular attention to the roots.
Try not to damage the roots as you unwrap your sapling or take it out of its container as they do not like to be disturbed.
If planted in the right place, red oak grows rather fast, putting on an average of two feet per year.
Site your tree somewhere with deep, freely draining soil and abundant sunshine.
Additionally, make sure you plant your tree in soil that is sufficiently acidic. The ideal pH range is 4.0 to 6.5, but it will tolerate a neutral pH of 7.0.
Trees that are planted in alkaline soils can become chlorotic, with pale, yellowing leaves. A simple soil acidity test can be purchased at Gardener’s Supply Company and takes about five minutes to complete.
Make sure your tree is situated somewhere that it can spread out its truly enormous crown of leaves. Red oaks can spread up to 75 feet when mature.
To plant your sapling, dig a hole the same depth and slightly wider than the root ball. Set the sapling carefully in the hole, making sure the bottom of the trunk is level with the soil and standing straight.
Pack the soil in firmly around the roots to remove air pockets and water in well.
Although this tree doesn’t like wet feet it will need to be watered regularly for the first year or two, until it is comfortably established. While these trees can do well on dry, rocky sites, that doesn’t mean they won’t appreciate supplemental watering when the weather is dry.
How to Grow Red Oaks
As with most natives, caring for Q. rubra is pretty straightforward. This tree is adapted to the vagaries of the climate within its large native growing range, and equipped with what it needs to defend itself against pests and pathogens.
Although this species does tolerate partly shady conditions it will grow a fuller, more symmetrical crown if planted in a sunny location and given lots of space.
Q. rubra is fairly forgiving on the moisture front, preferring slightly acidic, freely draining soils that often tend towards dry and lean, rather than moist and rich.
In the wild, red oak grows in a variety of soil types, provided they are well draining.
The most vulnerable time in the life of Q. rubra is the first year after planting while its roots are gaining purchase in the soil.
Make sure to water deeply once a week during this time, in the absence of rain. I like to turn the hose onto a tiny trickle and leave it at the base of the tree for a few hours.
If your specimen is planted in lean soil, a top dressing of compost in the spring will help, too.
- Situate plants in full sun to part shade.
- Water deeply once a week while the tree is becoming established and during dry spells.
- Plant in acidic to neutral soils.
- Provide plenty of space for the tree to spread its large crown.
As mentioned above, mature specimens don’t require anything in the way of maintenance except for some extra deep watering during dry spells.
In fact, it’s better to leave red oaks entirely to their own devices once their roots have penetrated deep into the ground.
Definitely put your clippers away as pruning makes these trees susceptible to disease-causing pathogens.
And please do not rake up their fallen leaves! Old foliage is essential to the critters that live and hibernate close to the soil through winter.
These dead leaves are also a source of nutrients for your tree as they gradually break down.
Another added bonus of leaving old, autumn leaves is you’ll provide your tree with a free source of mulch. Mulch can help keep weeds down, retain moisture, and provide nutrients as decomposition occurs.
Where to Buy
This is a fairly common species available at a wide range of local nurseries. It’s always worth asking where your nursery’s seed stock comes from.
Purchasing saplings grown from seed collected locally will produce plants that are uniquely adapted to your climate zone.
Q. rubra has a range from Georgia to Quebec and specimens hailing from each region will have different characteristics suited to that area.
Failing a local source, Nature Hills Nursery has saplings available for purchase online.
If you’re looking for a specific cultivar, you might be out of luck. There aren’t many. ‘Aurea’ has young foliage which is golden in color, and ‘Splendens’ has particularly bold red foliage in the fall, but both are difficult to find.
No matter, the straight species is all the beauty you need!
Managing Pests and Disease
Most of the pests and diseases you’re likely to encounter are nothing to worry about. Red oak is one of the toughest trees in North America and incredibly hardy once established.
It’s also one of the most important species of trees, ecologically speaking. A number of bugs, fungi and other critters, some deemed pests by humans, utilize Q. rubra to complete their life cycle.
Remember, when it comes to growing natives, just because something is nibbling your tree, doesn’t mean it’s bad, or needs management necessarily.
The following are common, non-harmful pests you may encounter:
- Acorn Weevils, Curculio spp.
- Carpenter Worms, Prionoxystus robiniae
- Columbian Timber Beetles, Corthylus columbianus
- Gall-Forming Cynapids, Callirhytis spp.
- Spongy Moths, Lymantria dispar
- Little Carpenter Worms, P. macmurtrei
- Acorn Moth Larvae, Blastobasis glandulella
- Filbertworm Moth, Cydia latiferreana
- Oak Timber Worms, Arrhenodes minutus
- Orange-Striped Oak Worms, Anisota senatoria
- Two-Lined Chestnut Borers, Agrilus bilineatus
- Variable Oakleaf Caterpillars, Heterocampa manteo
Oak wilt is a serious disease which certainly warrants your attention. Although the origin of this disease is unknown, it continues to spread throughout North America.
This disease is caused by a fungus (Bretziella fagacearum) that infects the water-carrying cells, known as xylem, of its host.
By cutting off the transport of water and other essential nutrients, this disease causes leaves to suddenly turn brown, wilt, and die. If infected, red oaks can die in a matter of weeks.
Unfortunately this disease spreads very rapidly from tree to tree. Sap beetles attracted to weakened specimens can spread the fungal spores further afield, so if you spot this disease in your area report it immediately to your local extension service or department of environmental conservation.
Oak wilt is most noticeable in spring and summer when the conspicuous brown leaves really stand out. Once it’s been detected, nothing can be done to save the tree.
You can, however, act quickly to save other oaks in your area by alerting the professionals.
Best Uses for Red Oak Trees
Renowned entomologist and ecologist Doug Tallmy heralds oaks as the best trees for supporting wildlife in the garden.
Red oaks are home to lichens, fungi, caterpillars, birds, beetles and small mammals. Undoubtedly the best use for this tree is as an oasis for wildlife.
Broad and imposing once mature, Q. rubra can double as a gorgeous shade and specimen tree for years to come.
Quick Reference Growing Guide
|Plant Type:||Deciduous tree||Foliage Color:||Greenish white or yellowish/green|
|Native to:||Central and eastern North America||Water Needs:||Moderate|
|Hardiness (USDA Zone):||4-8||Maintenance:||Low|
|Exposure:||Full sun to part shade||Soil Type:||Average, loam, clay, silt texture|
|Time to Maturity:||25 years||Soil pH:||4.0-6.5|
|Spacing:||20 feet||Soil Drainage:||Well-draining|
|Planting Depth:||2 inches (seeds), same depth as original container (transplants)||Uses:||Native plant garden, naturalizing, specimen tree, shade tree, wildlife garden|
|Common Pests and Diseases:||Acorn weevils, carpenter worms, Columbian timber beetles, gall-forming cynapids, spongy moths,little carpenter worms, acorn moth larvae, filbertworm moth, oak timber worms, orange-striped oak worms, two-lined chestnut borers, variable oakleaf caterpillars; oak wilt||Species:||Rubra|
Kings of the Forest
Long-lived, resilient, and important to wildlife of all shapes and sizes, the red oak is truly king of the forest.
Planting this species is not just an aesthetic choice, but an ecological and an ethical one, too. Grow Q. rubra in your backyard and reap the environmental benefits for years to come.
Do you have this species growing in your landscape? Tell us what animals you find munching on its leaves or acorns. Where did you plant your red oak and how did it go? Let us know in the comments!
And if you’d like to learn more about oak trees, check out these guides next: