Quercus suber (Cork Oak)

Quercus suber (Cork Oak) is a medium-sized evergreen oak with a dense, rounded crown and distinctive corky bark. Its leathery, oval leaves, up to 4 in. long (10 cm), are glossy dark green above and grayish beneath, with toothed margins. The trunk and main branches are covered with thick, deeply fissured bark marked by reddish-brown furrows, giving mature trees exceptional texture and character.

Cork Oak is best known for its remarkable bark, which is commercially harvested to produce wine corks and other cork products. During harvest, sections of the outer bark are carefully stripped from the living tree, which remains standing and can regenerate a new cork layer. This unusual ability allows repeated harvesting over the life of the tree without felling it.

Inconspicuous yellow-green flowers appear in spring, with male flowers borne in catkins and female flowers in small clusters. These are followed by egg-shaped acorns that provide an important food source for birds and small mammals. Long-lived, drought tolerant, and highly ornamental, Cork Oak makes an impressive shade, street, or specimen tree and is especially well suited to Mediterranean and dry western landscapes.

The oak genus includes many beloved trees, such as Live Oak, White Oak, Red Oak, Blue Oak, Bur Oak, and Pin Oak.

Oaks support an exceptionally wide range of butterfly and moth larvae. Species associated with oaks include the Banded Hairstreak (Satyrium calanus), Edward’s Hairstreak (Satyrium edwardsii), Gray Hairstreak (Strymon melinus), White-M Hairstreak (Parrhasius m-album), Horace’s Duskywing (Erynnis horatius), and Juvenal’s Duskywing (Erynnis juvenalis). Its acorns also provide valuable food for wildlife, including birds and mammals.

• Grows up to 40-70 ft. tall and wide (12-21 m).
• A full sun lover, this tree is easily grown in acidic, dry to medium moisture, well-drained soils. It tolerates some part shade but should not be planted in wet, poorly drained sites. Once established, it is drought tolerant. Drought-Tolerant Trees: Top Picks for Low-Water Landscapes
• Well suited as a specimen tree, shade tree, or street tree in Mediterranean and other dry-summer climates.
• Oaks may be affected by oak wilt, chestnut blight, shoestring root rot, anthracnose, oak leaf blister, canker, leaf spot, powdery mildew, scale, oak skeletonizer, leaf miners, galls, oak lace bugs, borers, caterpillars, and nut weevils.
• Toxic to horses if significant quantities of leaves or acorns are consumed.
• Native to southern Europe and northern Africa.