Turkish filbert (Corylus colurna)

Second place champion (tied) Turkish filbert in Boulder.

Species info:

Leaves: Simple, dark green, broadly ovate leaves resembling those of a littleleaf linden; coarsely toothed margins; turn yellow-brown to occasionally bright yellow in fall

Leaflets: N/A (simple leaves)

Leaf Surface: Smooth and glossy dark green in summer; turns duller with age

Bark: Mottled bark with patches of gray, green, orange, and brown; exfoliating and interlacing texture creates a striking ornamental appearance

Flowers: Inconspicuous; typical catkins of the filbert family, appearing before leaves emerge in spring

Fruit: Filbert nuts enclosed within a distinctive, frilly, leaf-like bract (modified leaf)

Botanical: Corylus colurna

Family: Betulaceae

Mature Height: 40–50 feet

Canopy Spread: 20–30 feet

Foliage Type: Deciduous

Tree Shape: Densely pyramidal when young, becoming pyramidal-oval to rounded at maturity

Fruit: Edible

Fall Color: Yellow-brown to bright yellow (occasionally)

Water Use: Moderate; drought tolerant once established

Hardiness: Zone 4 to 7

Soil Preference: Adaptable to somewhat alkaline soils; prefers well-drained soils and dislikes heavy clays that stay wet

Wildlife Value: Produces nuts valued by wildlife

Insects and Diseases: Very resistant to pests and diseases; even aphids rarely feed on it

Planting recommendation:

Information sources:

• Michael Dirr, Encyclopedia of Trees & Shrubs (Timber Press, 2011)

• Michael Dirr, Manual of Woody Landscape Plants (University of Georgia, 1990)

• Michigan State University Extension

• Colorado State University Extension