fbpx Sourwood | The Morton Arboretum


Sourwood in full flower.

 Sourwood is an attractive tree with white flowers in early summer and excellent fall color.  This tree requires an acid soil and thus can be difficult to grow in northern Illinois.

Botanical name:

Oxydendrum arboreum

All common names:

Sourwood, Sorrel tree, Lily-of-the-valley tree

Family (English):


Family (Botanic):


Tree or Plant Type:

  • Tree

Native Locale:

  • North America

Landscape Uses:

  • Specimen

Size Range:

  • medium tree (25-40 feet)

Light Exposure:

  • Full sun (6 hrs direct light daily),
  • Partial sun/shade (4-6 hrs light daily)

Hardiness Zones:

  • Zone 5 (Chicago),
  • Zone 6,
  • Zone 7,
  • Zone 8

Soil Preference:

  • Acid soil,
  • Moist, well-drained soil


  • Wet sites

Seasons of Interest:

  • early summer,
  • midsummer,
  • early fall,
  • mid fall

Flower Color & Fragrance:

  • Fragrant,
  • White

Shape or Form:

  • Oval,
  • Pyramidal

Growth Rate:

  • Slow

More Information:

Size and Form

This tree grows 25-30 feet high and 20-25 feet wide.  The form is pyramidal to oval.

Tree & Plant Care

The tree requires an acid soil.  Prefers a moist well-drained soil.
Full sun to part shade.

Disease, pests, and problems

No serious problems.

Native geographic location and habitat

Native primarily to the southeastern United States.
Common on well-drained upland slopes.

Bark color and texture 

Bark is gray-brown and deeply ridged with the ridges often divided in to a somewhat square pattern.

Leaf or needle arrangement, size, shape, and texture

Simple, alternate leaves with finely toothed edges.  Elongated shape and 3 to 8 inches long.
Leaves are dark green in summer changing to red or a mix of red and orange in fall.

Flower arrangement, shape, and size

Fragrant, white flowers in early summer.  The sprays of flowers are reminiscent of lily-of-the-valley in their shape.

Fruit, cone, nut, and seed descriptions

Small persistent dry capsules, tan in color.



Location of Oxydendrum arboreum (Sourwood) at the Arboretum