Tall and narrow shrubs, often called columnar or fastigiate varieties, are valuable solutions for modern landscape challenges. Their upright growth habit maximizes vertical space, making them ideal for small urban gardens, narrow side yards, and tight foundation plantings. These plants provide year-round structure and screening without the outward spread of traditional shrubs, effectively adding vertical accents where width is restricted.
Understanding the Columnar Growth Habit
The distinctly tall and slender shape of these shrubs is rooted in their genetics, a trait known as the fastigiate habit. This form results from branches that grow upward, nearly parallel to the main trunk, rather than spreading horizontally. The term “columnar” describes a plant whose height is generally five times its width, while “fastigiate” often refers to an even narrower, more pencil-like form, sometimes reaching a ten-to-one height-to-width ratio.
This habit is often the result of a spontaneous mutation or a specific genetic selection that disrupts the normal production or regulation of plant hormones, such as auxin. This hormonal change causes the plant to favor vertical growth and suppress wide-reaching lateral branches. Nursery professionals propagate these naturally occurring variants through grafting or cuttings to maintain the narrow profile.
Recommended Evergreen Varieties
Evergreen varieties are popular for providing year-round privacy screens and architectural structure. The ‘Emerald Green’ Arborvitae (Thuja occidentalis ‘Smaragd’) is a classic choice, growing 10 to 15 feet tall with a manageable width of 3 to 4 feet. This cultivar holds its rich green color well through cold weather and maintains a tight, pyramidal form without regular shearing.
For an even thinner profile, the ‘Skyrocket’ Juniper (Juniperus scopulorum ‘Skyrocket’) is exceptionally narrow, typically reaching 15 to 20 feet in height but only 2 to 3 feet wide. Its striking silvery-blue foliage offers a strong color contrast and thrives in full sun and dry, well-drained soil. A smaller, dense option is ‘Sky Pencil’ Holly (Ilex crenata ‘Sky Pencil’), which grows 6 to 10 feet tall yet only 1 to 3 feet wide. This Japanese holly is valued for its glossy, dark green leaves and naturally vertical shape, requiring no pruning to stay slim.
Recommended Deciduous and Flowering Varieties
Narrow deciduous shrubs introduce seasonal color and texture, often featuring flowers or dramatic fall foliage. The ‘Twombly’s Red Sentinel’ Japanese Maple (Acer palmatum ‘Twombly’s Red Sentinel’) is an excellent columnar choice, reaching 8 to 15 feet tall while staying compact at 2 to 6 feet wide. Its deeply lobed leaves emerge crimson-red in spring, turn a rich burgundy for summer, and finish with a spectacular scarlet color in autumn.
For spring interest, the ‘Adirondack’ Crabapple (Malus ‘Adirondack’) develops a columnar habit, growing 12 to 20 feet high with a spread of 6 to 10 feet. It provides a stunning display of fragrant white flowers from crimson buds in spring, followed by persistent bronze-red fruit that attracts birds in the fall and winter. The ‘Fine Line’ Buckthorn (Rhamnus frangula ‘Ron Williams’) forms a slender column 5 to 7 feet tall but only 2 to 4 feet wide. This variety features delicate, fern-like foliage that turns a soft golden-yellow in the fall, offering a fine texture that contrasts well with broader-leaved plants.
Placement and Maintenance for Narrow Shrubs
Narrow shrubs are commonly used for creating vertical accents and living screens. They work well planted on either side of an entryway or garage to frame the space, or spaced closely together to form a hedge in a tight corridor. Their compact root systems also make them suitable for large containers on patios or balconies, providing height without taking up floor space.
Selecting a site that provides full sun is necessary for dense foliage growth, as many columnar forms will thin out in too much shade. Well-drained soil is paramount. Maintenance is often minimal for genetically narrow cultivars. For evergreens like junipers and arborvitae, use thinning cuts to maintain the shape and allow light penetration. Avoid harsh shearing, which can lead to unsightly browning and an unnaturally dense outer layer that shades out interior branches.