How to Plant, Grow, and Care for Oak Trees

Oak trees belong to the genus Quercus and are members of the Beech (Fagaceae) family. There are more than 500 species of oak trees globally. Approximately 90 of these species are native to North America.

Oak trees come in a variety of sizes. Some can grow up to 80 feet tall and equally as wide, while the smallest species may grow no more than 10 feet tall. Most are deciduous in temperate climates, but some species in warmer climates are evergreen.

Regardless of their appearance and where they grow, these trees are an important part of the natural ecosystem. They provide abundant shade, excellent habitat for wildlife, and are useful trees for lumber.

Oaks are easy to grow and make excellent landscaping trees. And if you ever thought that an oak tree was “just a tree,” it’s time to reconsider. They are critical keystone species, and with so many species to choose from, you are sure to find one that’s ideal for your specific site and can grow well in your climate and soil type. 

If you are planting an oak in your yard, you aren’t just planting a tree. You are growing something beautiful and useful to you and to the wildlife inhabiting your neighborhood. Now, let’s dig into the basics of how to plant, grow, and care for these trees.

Natural History

Oak trees inhabit many different forest ecosystems. They are an important component of many hardwood forests and mixed hardwood forests.

Some oaks thrive in warm climates, while others live in cooler northern and mountaintop climates. Oaks have also been well used in urban settings, such as parks, along roadways, and as landscaping trees. These long-lived trees are known to live for over 1,000 years!

Oaks have long been incorporated into home and industrial purposes. They are commonly used for lumber, furniture, flooring, and many other useful and decorative items. Native Americans used the acorns as a food source, and some people today prepare and eat acorns. Take note that the acorns have a high tannin content, so they must be properly soaked before they can be eaten.

Oak trees have been classified into two major categories – red oaks and white oaks. It’s easy to tell the difference between the two classes. The red oaks have leaves with pointed ends and pointed lobes. Common examples of red types include pin oaks, black oaks, and scarlet oaks. The white oaks have rounded edges and rounded lobes. Common examples of white types include white oaks, bur oaks, and post oaks.

Characteristics

Oak trees are extremely diverse and come in many shapes and sizes. Some are short and shrubby, while others grow to be extremely large and majestic. And, of course, there is every size in between. 

Oak trees have single, simple, alternate leaves. There is a wide variety of leaf shapes, from simple, thin ovals to deeply lobed or toothed varieties. In the fall, many oaks display beautiful fall foliage in shades of yellow and orange or red and bronze, while others simply turn from green to brown without any notable color. 

Most oak trees are deciduous, but some are evergreen. Many species keep their leaves well into the fall, even after other deciduous trees have lost their leaves. A few are broadleaf evergreens in more southern climates and retain their green leaves through the winter. Oak tree bark is typically brownish-gray and furrowed. 

Oak trees bloom in the spring and have separate male and female flowers. The male flowers develop as elongated catkins, while the female flowers are tiny and quite inconspicuous, developing at the tips of budding twigs. Both male and female flowers appear at the same time and are wind-pollinated. Fertilized female flowers give way to the distinctive capped acorn, which contains the seed.

Propagation

Growing an oak tree from seed is easy and reliable. Acorns can be gathered from any mature tree and are free and convenient. 

Seed

It’s easy to collect oak tree seeds; just find a nice-looking oak tree, wait until fall, and pick up a few freshly fallen acorns. The acorns you choose for planting should be firm and solid with no holes, cracks, or soft spots. 

You can start your acorn in a pot or choose a spot in your landscape where you’d like a tree to grow. In the fall, after collecting the acorn, bury it under about an inch of soil and keep it moist. If you plant your acorn outside, there’s a high risk of it being eaten by small mammals. Protect your acorn until it has sprouted by covering it with a critter cage.

In early spring, the acorn will split and start developing a root, anchoring it into the soil. It will then send up a stem when the weather starts to warm, followed by the first true leaves. Seedlings will grow slowly but steadily each year. An oak grown from seed may take up to 20 or 30 years, or even longer, to start making its own crop of acorns.

Transplanting

If you buy a young nursery-grown tree in a pot, you must transplant it into your landscape. Early spring is the best time for transplanting, ideally before the tree breaks its dormancy. The next best times for transplanting trees would be anytime in the spring or late fall. 

Choose the Location

First, identify the location where you will plant your tree. Allow it plenty of space, and ideally, plant at least 60 or more feet away from other large trees, as well as from your house. Next, prepare the soil where you will plant your tree. Dig a hole the same depth as the pot in which your tree is currently growing and about three times as wide as the pot.

Planting Tips

Carefully remove the tree from the pot and place it in the hole. Position the tree to be upright and match the surface soil levels. Refill the hole with the soil you had previously removed. You don’t need to add anything special here; just reuse the same soil. Gently tamp down the soil around the base of the tree.

Immediately after transplanting, give your tree a thorough watering so that the water slowly sinks to moisten the root ball. Be careful not to just sprinkle the surface with water because the roots are well below the surface. Keep your young tree moist but not wet for the first several weeks. 

You can further help retain soil moisture by placing a layer of organic, biodegradable mulch a few inches deep around the base of the tree. Don’t pile the mulch up against the trunk of the tree, but rather spread out over the area where you dug and replaced the soil. The mulch helps retain soil moisture while discouraging weed growth. 

How to Grow

Oak trees are easy to grow and are generally low-maintenance, except for raking up the leaves in the fall. Most oak trees grow to a very large size. However, be sure to plant them in a location with enough space to accommodate the tree’s full expected height and width at maturity.

Sunlight

As a rule, most oaks prefer full sunlight with at least 6 hours of full sun daily. Most will also perform well with light partial shade, but if you plant them at a shaded edge of your yard, you will probably see them trying to lean towards the sun.

Water

Each species of oak will have slightly different watering preferences, but the good news is that if you grow a species native to your region, you shouldn’t need to do any supplemental watering because your tree is already perfectly adapted to your local conditions. Generally, oaks appreciate some regular moisture, which is usually fulfilled by natural rainfall.

Soil

Oak trees generally perform well in average-quality soil. Some species will thrive in organically rich soils, while others will do surprisingly well in poor-quality soil. Oaks appreciate well-drained soil, so they are not sitting in boggy conditions.

Climate and Temperature

Oak trees have varying degrees of cold and heat tolerance, depending on the species. If you live in a warm and humid climate, select a type that loves heat and humidity, like a live oak. If you live in a climate with long, cold winters, choose a cold-hardy variety like the white oak. 

Fertilizing

You shouldn’t need to fertilize your tree. These trees are perfectly well adapted to live in natural environmental conditions with average-quality soil.

Maintenance

Oak trees themselves are low maintenance. They do, however, shed a lot of leaves, and if you are trying to maintain a lawn or garden near an oak tree, you will find yourself raking up a lot of leaves.

Fortunately, these leaves make great weed-suppressing mulch for ornamental beds! It’s recommended to shred the leaves and/or compost them before adding to vegetable gardens.

If you are growing in a naturalized woodland garden, you can simply allow the leaves to stay on the ground, providing a natural forest floor setting. Don’t plant your tree too close to your house, or you will have a lot of acorns and leaves falling on your roof and clogging your gutters each fall.

Garden Design

Your woodland garden or naturalized area is an excellent location for this majestic tree. Oaks are a major component of many forest types, and if you have an area of your landscape that is a bit wild and natural, oak trees will fit right in. A woodland garden can be beautiful and extremely low-maintenance, so you can have plenty of time to just relax and enjoy a bit of nature in your yard.

Anyone wanting to increase the curb appeal of their home landscape should consider planting a tree. And what better tree than an oak? With species adapted to almost any environment, you are sure to find one that compliments your landscape and looks fabulous at the same time. Trees add structure, diversity, and year-round interest to any type of garden design.

Varieties

There are many beautiful varieties of oak trees, each with its own unique set of characteristics. No matter where you live, you will find an oak tree that will thrive and compliment your landscape. A few of the more common native species are listed here.

Live Oak, Quercus virginiana

Live oaks are commonly found in the southeastern United States and south into Mexico. These large trees can grow up to 80 feet tall but can spread as much as 100 feet across.

The widely sprawling branches give the live oak a characteristic look of often being wider than it is tall with thick and low horizontal branches. They are perfect for shady picnics on a hot summer day. Live oaks are evergreen and need warmer climates. They are only winter hardy in USDA Zones 8 to 10. 

Red Oak, Quercus rubra

Red oak is one of the more common species that grows across eastern North America. Red oaks grow to approximately 80 feet tall with a thick, straight trunk. These trees have lobed leaves, where each lobe ends with sharply pointed leaf tips.

In the fall, this species has showy reddish-brown foliage. Red oak grows in USDA Zones 4 to 8. Southern red oak (Quercus falcata) is a different species of red oak that’s more common in the southern states and hardy in Zones 6 to 9.

White Oak, Quercus alba

White oak trees are very common throughout the eastern United States. White oaks have deeply lobed leaves with smooth, rounded edges all around.

They can grow up to 80 feet tall and typically have a stout straight trunk, which becomes highly branched mid-way up with thick horizontal branches leading to a dome-shaped crown. In the fall, the white oak leaves turn to shades of brown and muted reds. They grow in USDA Zones 3 to 9.

Wildlife Value

Oaks are tremendously valuable for wildlife. They provide a habitat for birds to rest, nest, forage, and seek shelter. Many caterpillars feed on oak leaves, which may seem inconvenient for you but provides a wealth of food for many species of birds.

In fact, these caterpillars are a prime food source foraged by nesting birds to bring back to the nest to find their young. They provide a food source for butterflies and moths. Squirrels, deer, and a host of other mammalian wildlife forage on acorns, as do ducks and geese. 

Oak trees are a larval host plant for several species of butterfly and moth caterpillars. These species include the imperial moth, banded hairstreak, Edward’s hairstreak, gray hairstreak, white-M hairstreak, Horace’s duskywing, and Juvenal’s duskywing butterfly.

Common Problems

Most of the time, oak trees will grow trouble-free, but occasionally you will spot a problem. A healthy tree grown in ideal environmental conditions will naturally fight off infections, and you won’t need to do anything.

Since oak trees grow so tall, there is rarely anything you can do about pests and diseases anyway. Just be aware of some of the most common problems so if you see them, you will know what’s happening and respond appropriately.

Root Rot 

Root rot in oaks is generally caused by the Armillaria fungus. This fungus is common and widespread, attacking the roots of the tree and causing them to eventually rot.

If you notice clusters of honey-yellow mushrooms growing around your tree, followed by a slow decline in your tree’s health, your tree probably has Armillaria root rot. Unfortunately, there isn’t much to be done except not planting another oak in the vicinity because it will also likely be attacked by the same fungus.

Oak Wilt  

Oak wilt is a fungal disease that is often lethal for the tree. It is generally spread by infected beetles that carry the fungus from tree to tree, and it seems to be more common in red oaks than white oaks.

Oak wilt symptoms include yellowing of the leaf veins followed by uneven browning of the leaves and then finally by a rapid loss of leaves, usually by the middle of the summer. When oak wilt is present in a community of trees, it is nearly impossible to control. 

Chlorosis

Chlorosis occurs when your tree experiences a nutrient deficiency, typically due to the soil pH being too high. Ideally, the soil pH should be between 5.5 and 6.5. If your oak tree displays a general yellowing of the leaves, do a soil test to check your soil pH. If it is above 7, your tree will most likely suffer from chlorosis.

You can add soil amendments to help correct the soil pH. Check with your local county extension office for suggestions on how to proceed.

Caterpillars

A great number of butterfly and moth caterpillars feed on oak leaves. You may notice, in particular, large, colorful caterpillars known as oakworms. Oakworms are very numerous and can cause severe defoliation, which can be a problem in smaller, younger trees with fewer leaves.

Insect pests like caterpillars are difficult, if not impossible, to control on large trees. But since birds love to forage for caterpillars, you can invite birds to your yard as a natural pest control.

Insect Galls 

Insect galls are extremely common on oak tree leaves. A gall is usually a rounded swelling that is the tree’s response to various insects or mites that feed on oaks. You may see just a few galls, or you may see great numbers of galls on your tree.

Typically, galls are not a concern for the tree’s overall health but rather an unsightly inconvenience. If you see great numbers of gall-infected leaves on the ground, you can rake and dispose of these to reduce the number of insects emerging for the next generation of gall-inducing insects.

Frequently Asked Questions