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Sourwood (Oxydendrum arboretum) is an excellent specimen for park, street and residential settings. Suitable for Hardiness Zones 4-9, it excels in well drained soils, full to partial sun, and is drought and heat resistant.

Tree of the Month: Sourwood

By Leonard Phillips, ASLA Emeritus


Common Name: Sourwood

Botanical Name: Oxydendrum arboretum

Family: Ericaceae

Year of Introduction: 1747

Hardiness Zone*: 4 – 9

Height: 25 to 30 feet

Spread: 15 to 20 feet

Growth Rate: Slow, 15 feet in 15 years

Form: Pyramidal with round top and drooping branches

Bloom Period: June to early July for 2 to 4 weeks

Flower: White, 1/4-inch long, fragrant, cover the tree in blooms

Fruit: Brown capsule, persistent in winter

Spring Color: Bright green

Summer Foliage: Dark green

Autumn Foliage: Yellow, red, purple, often all colors on same tree

Winter Interest: Fruits provide interest in winter, bark also provides winter interest

Bark: Grayish brown to black, deep furrows and scaly ridges

Habitat: Species native to eastern half of US and Canada

Culture: Well drained soils, full to partial sun, drought and heat resistant, tolerates most soils, pH should be 5.5 – 6.5

Pest Resistance: None serious

Storm Resistance: Good to excellent

Salt Tolerance: Tolerant of salt spray

Planting: Transplant containers and B&B as young trees

Propagating: Seeds and tissue culture

Design Uses: Specimen for park, street, and residential

Companions: Use with low groundcovers planted the year after planting the tree   

Other Comments: Excellent attractive tree, specimen, group planting

Available From: Select retail nurseries.


* For information about the USDA Hardiness Zone Map, visit http://www.usna.usda.gov/Hardzone/index.html


These are the personal observations of the author, living in New England – Zone 6. Leonard Phillips can be reached via e-mail at lenphillips@on-line-seminars.com. Photo provided by Leonard Phillips.

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