Columnar shrubs are being used in a variety of ways in landscaping. One primary way they're being used is on small lots, which require landscaping that behaves itself and doesn't spread to neighbouring properties. Columnar shrubs can fit these tight spaces. Many of these shrubs do well not only in beds, but also in large containers. Columnar shrubs add a unique shape to landscaping and can be either evergreen or deciduous.
Ilex crenata, 'Sky Pencil' and Ilex vomitoria, 'Will Fleming,' are evergreen columnar shrubs with small, round, shiny leaves. These hollies are slow growing, need partial to full sun and do well in USDA Plant Hardiness Zones 6 through 11. At maturity they reach 10 feet and are 1 to 2 feet wide. They do not produce berries.
Buxus sempervirens, 'Green Tower,' and Buxus sempervirens, 'Graham Blandy,' are evergreen boxwoods with small shiny green leaves. Reaching 9 feet at maturity, these slender shrubs can be used in tight spaces but still deliver height. They can be planted in a range of soils and in sun to shade. Both varieties do well in USDA Plant Hardiness Zones 6 through 8. Unlike other boxwoods Green Tower will not turn brown in the winter.
Several junipers grow in the columnar habit. Blue Arrow, Skyrocket, Medora and Prairie Pillar are all slender and provide height. Blue Arrow, Skyrocket and Prairie Pillar reach a mature height of 15 to 20 feet, while Medora only grows 10 feet tall. These junipers stay 1 to 2 feet wide, with the exception of Medora, which can grow 3 feet wide. Blue Arrow offers nice silvery blue foliage, as well. Junipers are relatively easy to grow and are very tough plants. Most junipers do well in USDA Plant Hardiness Zones 3 through 8. They need partial to full sun and well drained soil. Once established, junipers are very drought tolerate.There are many upright juniper varieties. A few others that are worth mentioning are J. chinensis, 'Mountbatten' and J. chinensis, 'Iowa.'
Berberis thunbergi, 'Helmond's Pillar,' is a deciduous upright plant. The foliage is a dark burgundy offering a great deal of colour in tight spaces. This barberry reaches a mature height of 5 feet and stays only 2 feet wide. Barberries are easy to grow, require full sun and do well in USDA Plant Hardiness Zones 4 through 8.