The white oak is more than just Maryland’s state tree. It’s a living piece of our landscape, a provider of shade and shelter for wildlife, and a symbol of strength that can stand for centuries. At Rock Creek Tree, Turf & Landscape, we’ve been caring for white oaks and other native trees across Montgomery County since 2005, and we understand what these magnificent trees need to thrive.

If you have a white oak on your property, or you’re thinking about planting one, this guide will help you understand how to care for it properly so it stays healthy for generations.

Why White Oaks Matter in Maryland

White oaks (Quercus alba) are native to Maryland and grow throughout the entire state. They’re found in both upland and drier lowland areas, though they prefer well-drained soils. These trees are slow-growing but incredibly long-lived, often reaching 200 to 600 years of age.

The most famous white oak in Maryland was the Wye Oak in Talbot County, which stood for over 500 years before a storm took it down in 2002. At nearly 32 feet in circumference, it was a testament to just how massive and impressive these trees can become when given the right care and time.

White oaks provide critical resources for wildlife. Their acorns feed squirrels, turkeys, deer, and countless bird species. The leaves support butterflies and moths, and the branches offer nesting sites and shelter. Few tree species support as many other living things as the white oak.

Beyond their ecological value, white oaks produce some of the finest timber in North America. Their wood is prized for furniture, flooring, barrels for aging whiskey and wine, and even shipbuilding. The USS Constitution, known as “Old Ironsides,” was built with white oak.

Identifying White Oak Trees

White oaks are easy to identify once you know what to look for.

Leaves: White oak leaves have rounded lobes with shallow to deep sinuses (the spaces between lobes). Each leaf typically has 5 to 9 lobes. The edges are smooth and rounded, not pointed like red oak leaves.

Bark: Young white oaks have light gray bark. As the tree matures, the bark develops shallow furrows that become scaly and flaky with age. On older trees, you’ll see large, flaking plates on the upper trunk, while the lower trunk has shallower furrows. This distinctive bark pattern is one of the easiest ways to identify white oak in winter when leaves aren’t present.

Branches: White oaks have gray branches and typically develop a broad, rounded crown when grown in open spaces.

Acorns: White oak acorns mature in a single year, unlike red oak acorns, which take two years. The acorns are relatively sweet and are preferred by many wildlife species over the more bitter red oak acorns.

Planting White Oak Trees

If you’re planting a young white oak, timing and location make all the difference.

When to Plant

Plant white oak saplings in early spring after the last frost. This gives the tree the entire growing season to establish its root system before winter arrives.

Choosing the Right Location

White oaks need full sun to thrive. Young trees can tolerate some shade, but their tolerance decreases as they mature. For best results, plant your white oak where it will receive at least four to six hours of direct sunlight daily.

Make sure you have space. White oaks grow 50 to 80 feet tall and spread just as wide at maturity. Plant them well away from structures, driveways, and underground utilities.

Soil Requirements

White oaks prefer moist, well-drained, slightly acidic to neutral soil. They can adapt to different soil types and handle mild drought once established, but they struggle in alkaline, shallow, or heavily compacted urban soils.

Test your soil’s drainage before planting. Dig a hole, fill it with water, and see how long it takes to drain. If water sits for more than a few hours, you may need to improve drainage or choose a different location.

Planting Steps

Dig a hole as deep as the root ball and about twice as wide. This gives the roots room to spread without going too deep, which can suffocate them.

Place the sapling in the hole so the top of the root ball is level with the surrounding soil. Backfill with a mixture of native soil and compost, gently tamping down to eliminate air pockets.

Water thoroughly after planting. Apply a 2 to 3 inch layer of mulch around the base, keeping it a few inches away from the trunk to prevent rot.

Watering Your White Oak

Newly planted white oaks need consistent watering until they’re established, which typically takes one to two years.

Water deeply once or twice per week during dry periods. The goal is to keep the soil moist but not waterlogged. Deep watering encourages roots to grow down rather than staying shallow.

Once established, white oaks are fairly drought-tolerant. However, during extended dry spells, especially in summer, give your tree a deep soaking every few weeks. This is particularly important for trees growing in developed areas where competition for water is high.

Mulching

Mulching is one of the simplest and most effective things you can do for a white oak.

Spread a 2 to 3 inch layer of organic mulch (like shredded bark or wood chips) in a wide circle around the tree, extending out to the drip line if possible. Mulch helps retain moisture, regulates soil temperature, suppresses weeds, and gradually adds nutrients as it breaks down.

Keep the mulch a few inches away from the trunk. Piling mulch against the bark creates a humid environment that encourages rot and attracts pests.

Pruning White Oak Trees

Proper pruning keeps your white oak healthy, safe, and well-structured.

Only prune white oaks during winter dormancy, from December through February. This timing is critical because it minimizes the risk of oak wilt, a deadly fungal disease spread by sap-feeding beetles that are active in spring and summer.

Pruning during dormancy also allows the tree to heal before the growing season begins, and you’ll have a clear view of the branch structure without leaves blocking your way.

Focus on removing:

Dead or diseased branches: These are safety hazards and can spread problems to healthy parts of the tree.

Damaged wood: Storm-broken or cracked branches should come off cleanly.

Crossing or rubbing branches: Constant friction creates wounds that invite disease.

Weak angles: Branches attached at narrow angles (less than 30 degrees) are prone to breaking and should be removed when the tree is young.

Water sprouts and suckers: Vigorous vertical shoots growing from the trunk or base should be removed as they sap energy from the main tree.

Young trees benefit from developmental pruning, which shapes their structure and prevents problems later. Focus on establishing a strong central leader (the main trunk) and well-spaced scaffold branches.

Remove competing leaders and branches with weak attachments early. Pruning a small branch on a young tree is far easier and less stressful than removing a massive limb from a mature oak.

Mature white oaks need minimal pruning beyond removing dead branches and addressing safety concerns. Never “top” a white oak by cutting back all the branches to stubs. This practice is extremely harmful and often leads to tree death or structural failure.

For large branches, pruning near power lines, or work that requires climbing, call Rock Creek Tree. Professional arborists have the training, equipment, and insurance to handle high-risk pruning safely. We understand white oak biology and know how to make cuts that preserve the tree’s health and structure.

Common White Oak Diseases in Maryland

White oaks face several disease challenges in Maryland, though they’re generally more resistant than red oaks.

Oak Wilt

Oak wilt is a deadly fungal disease caused by Bretziella fagacearum. While it primarily affects red oaks, white oaks can also be infected. The disease has been detected in western Maryland, though it’s not widespread in most counties.

Symptoms in white oaks include scattered leaf browning starting at the margins, wilting leaves, and branch dieback. White oaks often survive for several years, losing a branch or two per year rather than dying rapidly like red oaks.

The disease spreads two ways. Above ground, sap-feeding beetles carry spores from infected trees to fresh wounds on healthy trees. Below ground, the fungus moves through root grafts between nearby oaks.

Prevention is critical. Only prune during winter dormancy when beetles aren’t active. If you must prune during the growing season, paint cuts immediately with latex paint to prevent beetle attraction.

Oak Anthracnose

Oak anthracnose is a fungal disease that causes small brown lesions on the undersides of leaves and twig dieback. It’s more of a cosmetic problem than a serious threat, but it can weaken trees over time.

To manage anthracnose, prune and remove affected branches during dormancy. In spring, a fungicide spray on new growth in previously affected areas can help prevent recurrence.

Bacterial Leaf Scorch

Bacterial leaf scorch is caused by the bacterium Xylella fastidiosa. It blocks the tree’s water-conducting vessels, causing symptoms that look similar to drought stress.

You’ll see scattered yellowing and browning of leaf margins throughout the canopy, typically appearing in late summer through fall. Leaves remain attached longer than with other diseases.

There’s no cure for bacterial leaf scorch. Trunk injections of antibiotics can suppress symptoms but won’t eliminate the infection. Keeping the tree healthy through proper watering and care helps it cope with the disease.

Hypoxylon Canker

Hypoxylon canker is an opportunistic fungus that attacks trees weakened by stress, drought, or other problems. Healthy white oaks typically resist infection.

Symptoms include yellowing or browning leaves, reduced twig growth, thinning canopy, and dead limbs. In later stages, bark falls off, exposing white, stringy sapwood and black fungal material.

The best defense is keeping your tree healthy through proper watering, mulching, and avoiding injury to the trunk and roots.

Common White Oak Pests in Maryland

Two-Lined Chestnut Borer

The two-lined chestnut borer is a native beetle that attacks stressed or weakened white oaks. Drought, root injury, soil compaction, and other stress factors make trees vulnerable.

Adult beetles are greenish-black with two yellow stripes and about 1/5 to 1/2 inch long. The larvae feed under the bark, cutting off the tree’s flow of food and water.

Symptoms include branch dieback, wilted foliage, and sudden browning of leaves.

Prevention is the best strategy. Keep your trees healthy through proper watering, mulching, and avoiding trunk damage. Healthy trees rarely attract this pest.

Spongy Moth (formerly Gypsy Moth)

The spongy moth is an introduced pest that feeds on white oak leaves, along with many other tree species. Heavy infestations can completely defoliate trees.

Caterpillars feed from May through June. While a healthy tree can usually recover from one year of defoliation, repeated attacks weaken the tree and make it vulnerable to other problems.

Control options include physical removal of egg masses in winter, banding trees to trap caterpillars, and biological controls like Bt (Bacillus thuringiensis). For severe infestations, contact a professional.

White Oak and Maryland’s Changing Climate

Maryland’s climate has been experiencing more extreme weather in recent years, including periods of heavy rainfall followed by drought. These swings stress trees and make them more vulnerable to disease and pests.

White oaks can handle these challenges better than many species, but they still need support during extreme conditions. Water during extended dry periods, ensure good drainage during wet spells, and maintain a healthy layer of mulch to buffer temperature and moisture fluctuations.

The White Oak Initiative

Because of changes in land management and longer harvest cycles, white oak regeneration is declining in forests. The White Oak Initiative was established to reverse this trend and ensure these critical trees remain a part of our landscape for future generations.

As a homeowner, you can support white oak conservation by planting and caring for white oaks on your property, protecting existing mature trees, and working with professionals who understand the importance of this species.

When to Call Rock Creek Tree

White oaks are resilient trees, but they benefit from professional care at key times.

Call us if:

• Your white oak shows signs of disease or pest damage
• Large branches need pruning
• Storm damage has created hazards
• The tree is declining without an obvious cause
• You’re planning construction near a mature white oak and need guidance on protecting its roots
• You want a professional assessment of your tree’s health

At Rock Creek Tree, we understand Maryland’s native trees and the specific challenges they face in our region. We’ve been caring for white oaks and other species across Montgomery County since 2005, and we’re here to help your trees thrive.

Contact Rock Creek Tree at 301-945-7677 or visit rockcreektreeturflandscape.com for professional white oak care.