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Sourwood Oxydendrum arboreum

Other Common Name(s):

Previously known as:

  • Andromeda arborea
  • Lyonia arborea
Phonetic Spelling
ok-see-DEN-drum ar-BOR-ee-um
Description

Sourwood is a deciduous small tree that may grow 20 to 30 feet tall. The tree has alternate leaves that are finely toothed and sour to the taste. The bark is red-brown with deep vertical furrows that separate flat, pointed ridges. In mid-summer, small, white, urn-shaped flowers mature on panicles. The tree produces 5-valved capsules borne on panicles that mature in the fall and release the very tiny, 2-winged seeds. Fall foliage is red to reddish-purple. Terminal inflorescences resemble the elongated, bony fingers of a witch. This plant makes an excellent specimen plant, blooms in early summer, and blooms up the axis. Blooms are effective for 3-4 weeks. Flowers are fragrant and bloom poorly in the shade.

This plant prefers acidic, peaty, moist, well-drained soils in full sun to part shade. It is tolerant of shade and dry soils and moderately tolerant of salt. It is intolerant of pollution and urban areas. It has a slow growth rate and no serious pest or disease problems. It makes an excellent specimen or understory tree or planted in small groups in a woodland garden.

It gets its common name, Lily of the Valley Tree, because its flowers look similar to those of the Lily of the Valley plant. Honey made from the nectar of these flowers is highly prized for its color and flavor.

Fire Risk: This plant has a low flammability rating.

Seasons of Interest: 

     Leaves:  Fall    Bloom:  Summer     Fruit/Seed/Nut:  Fall

 Insects, Diseases, or Other Plant Problems:  Fall webworm is an occasional problem. Leaf spot and twig blight infrequently occur on the Sourwood tree.  This plant does not like to be transplanted so only do so with young plants.

Quick ID Hints:

  • Tree shrublet with laurel-like leaves
  • Leaves are minutely serrulate and are red in fall
  • Inflorescence is terminal, resembles a bony witch's hand
  • Flowers are urceolate, white, and drooping
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See this plant in the following landscape:
Cultivars / Varieties:
  • 'Chameleon'
'Chameleon'
Tags:
#bees#fragrant#red#showy flowers#deciduous#fall color#specimen#wildlife plant#showy#native tree#salt tolerant#winter interest#fall interest#understory tree#flowering tree#playground#year-round interest#showy fruits#reptiles#honey#cpp#low flammability#NC native#insect pest tolerant#bats#amphibians#deer resistant#children's garden#fire resistant#pollinator plant#fantz#food source fall#food source nectar#food source pollen#piedmont mountains UPL#small group plantings#bird friendly#food source hard mast fruit#mammals#fall color red#butterfly friendly#nectar plant early summer#nectar plant mid-summer#Coastal FACU#pollinator garden#audubon#woodlands
 
Cultivars / Varieties:
  • 'Chameleon'
'Chameleon'
Tags:
#bees#fragrant#red#showy flowers#deciduous#fall color#specimen#wildlife plant#showy#native tree#salt tolerant#winter interest#fall interest#understory tree#flowering tree#playground#year-round interest#showy fruits#reptiles#honey#cpp#low flammability#NC native#insect pest tolerant#bats#amphibians#deer resistant#children's garden#fire resistant#pollinator plant#fantz#food source fall#food source nectar#food source pollen#piedmont mountains UPL#small group plantings#bird friendly#food source hard mast fruit#mammals#fall color red#butterfly friendly#nectar plant early summer#nectar plant mid-summer#Coastal FACU#pollinator garden#audubon#woodlands
  • Attributes:
    Genus:
    Oxydendrum
    Species:
    arboreum
    Family:
    Ericaceae
    Life Cycle:
    Woody
    Country Or Region Of Origin:
    Eastern and southern United States
    Fire Risk Rating:
    low flammability
    Wildlife Value:
    The flowers are attractive to butterflies and other insects. Natural hollows in these trees are refuge for climbing reptiles and amphibians, bats and other small wildlife. Old fall webworm tents attract invertebrates that birds often eat during late fall and winter. Flowers are quite attractive to bees and the honey is highly sought after.
    Play Value:
    Attractive Flowers
    Attracts Pollinators
    Buffer
    Wildlife Food Source
    Particularly Resistant To (Insects/Diseases/Other Problems):
    Resistant to fire. Moderately resistant to deer damage. Heat and drought Tolerant.
    Dimensions:
    Height: 20 ft. 0 in. - 30 ft. 0 in.
    Width: 10 ft. 0 in. - 15 ft. 0 in.
  • Whole Plant Traits:
    Plant Type:
    Native Plant
    Tree
    Woody Plant Leaf Characteristics:
    Deciduous
    Habit/Form:
    Pyramidal
    Rounded
    Growth Rate:
    Slow
    Maintenance:
    Low
    Texture:
    Medium
  • Cultural Conditions:
    Light:
    Dappled Sunlight (Shade through upper canopy all day)
    Deep shade (Less than 2 hours to no direct sunlight)
    Full sun (6 or more hours of direct sunlight a day)
    Partial Shade (Direct sunlight only part of the day, 2-6 hours)
    Soil Texture:
    High Organic Matter
    Soil pH:
    Acid (<6.0)
    Soil Drainage:
    Good Drainage
    Moist
    Occasionally Dry
    Available Space To Plant:
    12-24 feet
    NC Region:
    Coastal
    Mountains
    Piedmont
    USDA Plant Hardiness Zone:
    5b, 5a, 6a, 6b, 7b, 7a, 8b, 8a, 9b, 9a
  • Fruit:
    Fruit Color:
    Brown/Copper
    Fruit Value To Gardener:
    Showy
    Display/Harvest Time:
    Fall
    Fruit Type:
    Capsule
    Fruit Length:
    < 1 inch
    Fruit Description:
    5-valved brownish dehiscent dry capsules that ripen to silver-gray in September and October. Capsules contrast well with the red fall color and provide continuing ornamental interest after leaf drop into winter.
  • Flowers:
    Flower Color:
    White
    Flower Inflorescence:
    Panicle
    Flower Value To Gardener:
    Fragrant
    Showy
    Flower Bloom Time:
    Summer
    Flower Shape:
    Bell
    Flower Petals:
    4-5 petals/rays
    fused petals
    Flower Size:
    < 1 inch
    Flower Description:
    Waxy, lily-of-the-valley-like, white bell-shaped flowers that bloom on slender, second on axis, drooping, one-sided slender terminal panicles (4-8” long) from June to July. Branches are narrow, elongate, decurved then swept upright, and persist after leaves. Flowers have a 5 lobed calyx and an urceolate corolla that is finely downy, white, 5-lobed, and minute. The flowers themselves have a slight fragrance and are 1/4" long. The panicles persist after flowers drop and resemble long fingers.
  • Leaves:
    Woody Plant Leaf Characteristics:
    Deciduous
    Leaf Color:
    Gold/Yellow
    Green
    Purple/Lavender
    Leaf Feel:
    Glossy
    Leaf Value To Gardener:
    Showy
    Deciduous Leaf Fall Color:
    Gold/Yellow
    Purple/Lavender
    Red/Burgundy
    Leaf Type:
    Simple
    Leaf Arrangement:
    Alternate
    Leaf Shape:
    Elliptical
    Lanceolate
    Oblong
    Leaf Margin:
    Entire
    Serrate
    Hairs Present:
    No
    Leaf Length:
    > 6 inches
    Leaf Width:
    1-3 inches
    Leaf Description:
    Alternate, simple, finely-toothed, glossy green leaves (5-8” long to 1"-3" wide) entire to serrate margin shiny and glossy, reminiscent of a peach leaf. They are elliptic to oval or oblong-lanceolate, acute, minnutely serrulate, thin, accuminate, and broadly cuneate. They have a sour taste, hence the common name. They produce consistently excellent fall color, typically turning crimson red but sometimes yellow and purple.
  • Bark:
    Bark Color:
    Dark Gray
    Light Gray
    Surface/Attachment:
    Ridges
    Bark Description:
    Dark gray bark on mature trees is has light gray fissures, ridged and scaly, becomes blocky with age.
  • Stem:
    Stem Color:
    Brown/Copper
    Stem Is Aromatic:
    No
    Stem Bud Terminal:
    Only 1 terminal bud, smaller than side buds
    Stem Surface:
    Smooth (glabrous)
    Stem Description:
    Stems are slender, glabrous or sparingly pubescent, and do not go dormant in the winter. Twigs are seemingly terminated by a leaf and bud, but bud is axillary and minute stem growth is adjacent. Buds are lateral or axillary, small (less than an inch in size), are conical-globose, and sessile.
  • Landscape:
    Landscape Location:
    Coastal
    Recreational Play Area
    Woodland
    Landscape Theme:
    Butterfly Garden
    Children's Garden
    Native Garden
    Pollinator Garden
    Design Feature:
    Flowering Tree
    Shade Tree
    Small groups
    Specimen
    Understory Tree
    Attracts:
    Bees
    Butterflies
    Pollinators
    Small Mammals
    Songbirds
    Resistance To Challenges:
    Deer
    Dry Soil
    Fire
    Salt