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Broadleaf Deciduous Trees
Oxydendrum arboreum
sourwood
Ericaceae
Eastern North America from Pennsylvania south to Florida and west to Indiana and Louisiana; understory tree in deciduous and mixed forests on well-drained acidic soils
At a Glance
TypeTree
HabitUpright
FoliageDeciduous
Height25–40 feet (7.5–12 m)
Width15–25 feet (4.5–7.5 m)
Maturity17 years
Growing Zones
USDA Hardiness Zones
5 - 9Zone 5
Zone 6
Zone 7
Zone 8
Zone 9
These zones indicate the coldest temperatures this plant can typically survive.
Frost Tolerancehardy
Key Features
Attracts Pollinators
Attracts Butterflies
Deer Resistant
Fragrant (light)
Native to North America
Maintenancevery low
Overview
A slow-growing, pyramidal deciduous tree reaching 25–40 feet (7.5–12 m) tall and 15–25 feet (4.5–7.5 m) wide, native to eastern North America. In July–August, when few other trees are in bloom, sourwood produces pendulous panicles 8–12 inches (20–30 cm) long of small white fragrant urn-shaped flowers. These develop into persistent silvery-gray seed capsules through winter. Fall color is intense scarlet, crimson, and burgundy — among the most reliable of any Pacific Northwest landscape tree. Leaves lance-oblong, glossy dark green with an acidic taste when chewed. Requires acidic soil — a member of Ericaceae. Hardy in USDA zones 5–9.
Native Range
Oxydendrum arboreum is native to eastern North America from Pennsylvania south to Florida and west to Indiana and Louisiana, growing as an understory tree in deciduous and mixed forests on well-drained acidic soils. The sole species in the genus and the only tree in Ericaceae native to eastern North America.Suggested Uses
Planted as a specimen or small to medium shade tree at 15–20 foot (4.5–6 m) spacing in acidic woodland garden settings. Midsummer flower display, simultaneous late-summer flowers-fall color-capsule display, and spectacular fall scarlet make it one of the most rewarding four-season trees for Pacific Northwest woodland gardens. Thrives in the naturally acidic soils common throughout the Pacific Northwest. Sourwood honey from the flowers is prized for its distinctive flavor.How to Identify
Appearance
Size & Dimensions
Height25' - 40'
Width/Spread15' - 25'
Reaches mature size in approximately 17 years
Colors
Flower Colors
white
Foliage Colors
green
Fall Foliage Colors
red
scarlet
burgundy
crimson
Bloom Information
Bloom Period
~4 weeksJ
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Summer
Detailed Descriptions
Flower Description
Small white urn-shaped flowers 0.25 inch (6 mm) long in pendulous panicles 8–12 inches (20–30 cm) long; fragrant; resembling lily-of-the-valleyFoliage Description
Lance-oblong, 4–7 inches (10–18 cm) long, glossy dark green with finely toothed margins; acidic taste when chewed; brilliant scarlet to crimson-burgundy fall color — among the most reliable of any PNW landscape treeGrowing Conditions
Sun Requirements
Full Sun
Partial Shade
Requires 4-10 hours of direct sunlight daily
• Full Sun: 6+ hours of direct sunlight
• Partial Shade: 3-6 hours of direct sunlight
• Full Shade: Less than 3 hours of direct sunlight
Soil Requirements
pH Range4.5 - 6.0(Acidic)
357912
Soil Types
loamsand
Drainage
well drained
Water & Climate
Water Needs
Medium
Frost Tolerance
hardy
Time to Maturity
15–20 years
Care & Maintenance
Care Guide
Plant in full sun to part shade in moist, well-drained, acidic soil (pH 4.5–6.0). Acidic conditions are essential — a member of Ericaceae. Does not tolerate alkaline soils or compacted urban soils. Space 15–20 feet (4.5–6 m) apart. Water regularly, especially during dry summers. Mulch generously to retain moisture and maintain soil acidity. Slow-growing — approximately 6–12 inches (15–30 cm) per year.Pruning
Requires minimal pruning. The naturally pyramidal form requires no shaping. Remove dead or crossing branches in late winter. Stake young trees to establish a single central leader.Pruning Schedule
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early spring