Bur oak (Quercus macrocarpa)
The majestic Bur oak (Quercus macrocarpa) is a large, durable shade tree thriving in zones 3-8 with excellent drought tolerance.
Complete Plant Information
Overview
The Bur oak (Quercus macrocarpa) stands out as one of the most architecturally stunning and resilient native North American oaks. Gardeners value this long-lived, deciduous white oak group member for its massive, rounded crown capable of casting substantial shade for generations. It is renowned for its adaptability across various challenging soil types, especially when positioned in full sun.
One of the most distinctive features of Quercus macrocarpa is its large acorn, which is partially enclosed by a heavily fringed or ‘burry’ cup, giving the tree its common name. This magnificent specimen provides crucial ecological benefits, serving as a primary food source for numerous wildlife species throughout the region.
While the Bur oak is undeniably slow to establish prolific acorn production—sometimes taking decades—its ultimate reward is a truly majestic landscape anchor known for requiring relatively low maintenance once established. Plan for significant space, as this giant readily reaches heights and spreads of 60 to 80 feet.
Fast Facts
- Plant Family: Fagaceae
- Plant Type: Tree
- Native Range: Northern and central United States, southeastern Canada
- Hardiness Zones: USDA Zones 3-8
- Size at Maturity:
- Height: 60-80 ft
- Spread: 60-80 ft
- Bloom Time: April
- Bloom Description: Yellowish-green
- Sun Exposure: Full sun
- Water Needs: Dry to medium
- Maintenance Level: Low
How to Grow
The best time to plant young Bur oak (Quercus macrocarpa) specimens is during the dormant season, ideally in early spring or late fall, allowing the roots time to establish before summer stress. Select a site that receives full sun exposure, as light is crucial for this species. While adapted to many situations, it performs best in average, well-drained soils, though it demonstrates excellent adaptability to clay and drier conditions once mature.
Watering should focus on deep, infrequent soaking, especially during the initial years after planting, allowing the soil to dry slightly between waterings to encourage deep root growth suited to its dry-to-medium water needs. Generally, fertilization is unnecessary for mature specimens unless soil deficiencies are identified, keeping in mind that the tree naturally bears its first substantial acorn crop potentially after 35 years.
Maintenance for the Bur oak is considered low. Pruning, if required, should focus only on removing damaged or crossing limbs, preferably during dormancy. Be patient regarding fruit production, and understand that while it adapts to various soils, best growth is historically documented in moist, well-drained bottomland soils.
Landscape Uses
The towering presence of the Quercus macrocarpa makes it an unparalleled choice for foundational plantings in expansive landscapes requiring significant shade. It excels as a specimen tree in large lawns, parks, or along wide avenues where its broad, spreading canopy can fully develop without constraint. Due to its impressive drought tolerance once established, it is an excellent candidate for rain gardens or naturalized areas where supplemental watering may be inconsistent.
When planning companion plantings around this oak, consider species that share its preference for high light and can tolerate dry summer spells, such as certain native prairie grasses or deep-rooted perennials. Avoid placing shallow-rooted shrubs too close, as competition for water and nutrients near the base can stress smaller plants.
The sheer scale of the Bur oak dictates its use primarily on large properties. It functions beautifully as a focal point, drawing the eye upwards, or as a crucial element in creating an ecological corridor, especially given the wildlife value of its acorns.
Standout Features
Flower Qualities
- Insignificant
Fruit Qualities
- Showy
Noteworthy Characteristics
The Bur oak (Quercus macrocarpa) is rightfully considered one of North America’s most majestic native oaks, recognized by its broad, spreading crown reaching 60 to 80 feet tall. Its defining feature is the large acorn encased in a distinctive, fringed, burry cup that covers half to three-quarters of the nut. The heavy, leathery leaves typically display 5 to 9 rounded lobes, which often create a waisted appearance near the midrib.
Tolerances
- Drought
- Clay Soil
- Dry Soil
Potential Problems
Like all oaks, the Bur oak can be susceptible to a broad range of pests and diseases, including Oak Wilt, anthracnose, and various leaf spot fungi. Monitoring leaf health during the growing season is key to early intervention for most common issues.
Potential insect nuisances include borers, various scale insects, and the oak lace bug, which can cause aesthetic damage but rarely threatens the life of a healthy, mature tree. Given its inherent vigor and longevity, the Bur oak is often praised as a low-maintenance choice, provided attention is paid to initial planting site health.
Frequently Asked Questions
What hardiness zones is Bur oak suitable for?
The Bur oak (Quercus macrocarpa) is ideally suited for USDA Hardiness Zones 3 through 8.
How large does Quercus macrocarpa grow?
This magnificent shade tree typically matures to a height between 60 and 80 feet, matching its spread of 60 to 80 feet at maturity.
What sun exposure does Bur oak need?
Quercus macrocarpa requires full sun exposure to achieve the best growth habit and vigor.
When does Bur oak bloom?
Blooming occurs in April, marked by inconspicuous, yellowish-green flowers borne in separate male and female catkins as the leaves emerge.
Conclusion
The Bur oak provides unmatched stature and durability, making it a superb investment for long-term landscape planning due to its low maintenance needs and remarkable tolerance for difficult soils. Integrating Quercus macrocarpa into large properties offers substantial shade and critical wildlife support via its large acorns. Before planting, ensure you have the space required for its 80-foot spread and confirm the site offers full sun exposure.
Wildlife Benefits
The most significant ecological role of the Bur oak is undeniably its fruit. The large, edible acorns, encased in their unique burry cups, are a vital, high-fat food source heavily relied upon by deer, squirrels, jays, and various other woodland creatures preparing for winter. Planting this oak contributes directly to local biodiversity.
Furthermore, due to its broad, dense branching structure, the established canopy of the Quercus macrocarpa provides superb nesting and roosting habitat for numerous bird species. Its long lifespan ensures that this ecological contribution persists across many decades.
Design Ideas
For properties requiring monumental scale blending formality with naturalism, the Bur oak serves as a perfect anchor. Groupings of three or five specimens, spaced widely apart, can define the boundaries of large open meadows or frame long driveways, offering visual weight and architectural interest.
Because this tree adapts well to dry and clay soils, it integrates seamlessly into xeriscaping plans or sites bordering woodland edges where soil conditions might be less than ideal for cultivated favorites. Its rugged texture contrasts nicely with fine-textured evergreens or ornamental grasses planted beneath its canopy drip line.
