Colorado State University researchers continue to evaluate over 1,300 taxa of woody plants for adaptability, ornamental flowers, fruit, fall color and pest problems. Of recent interest, are woody plants with a columnar growth habit that can be planted in residential areas with limited space between homes. The plants presented here are proven adaptable to Colorado conditions.

Carpinus betulus ‘Frans Fontaine’ (Frans Fontaine Hornbeam) 

The narrow, columnar shape of this tree is maintained to maturity. It grows to about 20 to 30 feet in height with a width of 10 to 15 feet. Its dark green leaves turn yellow in the fall.

Tips & Tricks: The current season’s growth curves inward toward the central leaders.

Juniperus scopulorum ‘Woodward’ – Woodward Rocky Mountain Juniper (pictured right)

This juniper was organically found in western Oklahoma and has a narrow/columnar growth habit with blue/green needles. A Plant Select® recommendation, the plant is well adapted to Colorado conditions. It appears to be a male since no fruit has been observed.

Tips & Tricks: It is a good tall screening juniper and appears less prone to snow damage but could be in limited supply.

Quercus robur x alba ‘Crimschmidt’ – Crimson Spire™ Oak

Crimson Spire is a hybrid of white oak and columnar English Oak that is resistant to powdery mildew. It has a columnar/fastigiate growth habit with blue green foliage that turns rusty red in fall. It is adapted to more alkaline soil and matures to a height of about 45 feet tall and 15 feet wide.

Tips & Tricks: It is a great choice where a tall narrow tree is needed and holds brown leaves though winter.

Hibiscus syriacus ‘Gandini Santiago’ Purple Pillar™ Rose of Sharon (pictured right)

This clone has a columnar growth habit that grows 10 to 15 feet tall and 2-3 feet wide. The flowers— short-lived, sterile and semidouble— are pink with a purple eye and bloom from July to September. Once established, the plant can tolerate heat and dry soils.

Tips & Tricks: It is a good vertical accent shrub which can be used as a tall screen.

Read the rest of CSU’s recommendations in the July-August 2019 issue of Colorado Green magazine.

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