Sourwood (Oxydendrum arboreum) - white flowers, illustrated plant cardIllustration

Sourwood

Oxydendrum arboreum

Also called sorrel tree

Sourwood blooms from June through July.

Bloom calendar
Bloom time
Jun–Jul
checked
Hardiness
Zones 5–9
checked
Sun
Full sun
checked
Water
Moderate water
checked
Mature size
28 ft × 17 ft
checked
Type
Tree
house classification

Months here are Northern Hemisphere months; in the Southern Hemisphere, shift them by six months.

Growing Sourwood

Plant it in full sun. It prefers moderate water. It is hardy in USDA zones 5–9. Expect it to reach about 28 ft tall and 17 ft wide at maturity, in roughly 12 years (a house reading).

Pets

  • Not yet checked for pets.

Lists differ and none is complete. If a pet eats a plant and seems unwell, call a veterinarian or a pet poison helpline.

No toxicity note is on file for Sourwood. That is not a clearance: check its safety for people and pets before planting.

Verification
What was checked

Nine facts were checked against named botanical sources, each recorded beside the sources that carried it: mature height and spread, hardiness zones, sun, water, bloom months and color, the trait tags, and years to mature size, which rests on a recorded house rule where no publisher states one and is marked so. Soil, diseases, pests, toxicity and the plant's own names have not yet been read for this plant, and its trait tags are the ones a feature uses rather than every word a page prints. Each fact above carries its own mark. The planting, spacing and size sections are derived from these checked facts by a fixed rule, not checked separately, and the plant type is the library's own classification.

See the 8 sources it was checked against

When to plant Sourwood

Plant Sourwood in early spring as soon as the soil is workable, or in early fall at least six weeks before your first frost, so roots establish in cool weather. In zone 7, the middle of its hardy zones 5 to 9, spring means March to May and fall means September or October. Once settled, it blooms from June to July.

Month-by-month timing for your zone is on the planting calendar; if you garden near zone 7, the middle of this plant's hardy range, start with zone 7 in March. Derived from the plant's category, zones and bloom months plus typical zone frost dates, not checked separately.

How big does Sourwood get?

Illustration of Sourwood drawn to scale beside an adult28 fttall5 ft 7 inan adult17 ftwide
About 28 ft tall and 17 ft wide at maturity: about 5 times as tall as an adult.

See Sourwood in a garden plan: the planner shows it in 3D beside everything else you add, growing toward this size over the years.

How far apart to plant Sourwood

Derived from the mature spread above by a fixed rule, not checked separately: spacing is the spread, center to center.

Give Sourwood about 17 ft of clear ground in every direction, measured from its center. It is one plant with room around it, not a row, and a raised bed is too small for it.

Clear ground around it
17 ft in every direction

Add Sourwood to a garden plan and the planner draws it at its full width, so you see the spacing before you buy.

Where these facts come from

Sourwood's height, spread, hardiness zones, sun, water, bloom months and color and trait tags were checked against 8 published sources on October 25, 2026. Each one is linked below with every fact it carried, which can include a fact this page still marks as not yet checked, because a source carrying a value is not the same as the value being held to the standard. Facts not in that list, and the planting, spacing and size sections, are not covered by these sources.

  • Missouri Botanical Gardenheight, spread, hardiness zones, sun, water, bloom months and color and trait tags
  • NC State Extensionheight, spread, hardiness zones, sun, water, bloom months and color and trait tags
  • woodyplants.cals.cornell.eduCornell Universityheight, spread, hardiness zones, water, bloom months and color and trait tags
  • pubs.ext.vt.eduVirginia Cooperative Extensionheight, spread, hardiness zones, water and bloom months and color
  • plantdatabase.uconn.eduUniversity of Connecticutheight, hardiness zones, sun and bloom months and color
  • plantfinder.nativeplanttrust.orgNative Plant Trustheight, spread, hardiness zones and water
  • RHSRoyal Horticultural Societyheight, water and bloom months and color
  • nwmissouri.eduNorthwest Missouri State University, Missouri Arboretumheight, spread and hardiness zones

How the checking works, and what each standard covers, is on the verified plants page.

Where it grows wild

Native to 16 states

United States: Alabama, Florida, Georgia, Indiana, Kentucky, Louisiana, Maryland, Mississippi, New York, North Carolina, Ohio, Pennsylvania, South Carolina, Tennessee, Virginia, West Virginia and 4 more

Recorded growing wild in 550 counties.

Range data from the World Checklist of Vascular Plants, Royal Botanic Gardens, Kew (CC BY 4.0, adapted) and USDA PLANTS. How the native range is credited.

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