I still remember the amazing 30-foot-high beech hedge (if memory serves, it was a selection of European beech, Fagus sylvatica) at the Edinburgh (Scotland) Botanic Garden. Even though it was February, the smooth gray bark and golden-brown leaves made a dramatic impact. Ever since then, I have thought about hedges and the role they play in the landscape.

One of the most common uses for a hedge is privacy, often as a green alternative to a structure like a fence or wall. Hedges also create enclosure, separate planting beds from pathways, provide a transition from a formal area to a woodland, and serve as a backdrop for other plantings. Formal or informal, deciduous or evergreen, they take on many roles in the landscape.

ERICA GLASENER/Special (ENLARGE)

A holly hedge serves to demarcate space and provides privacy and an attractive dark green backdrop for a bench.

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Formal hedges are usually sheared to a precise size and may require trimming three or more times a year to maintain a particular shape. Although many types of plants make effective hedges, some of the best selections for formal use have small needles or leaves and dense branching.

When choosing plants for informal hedges, the size of the foliage is not as important. Maintaining a naturalistic style usually requires an overall pruning only once a year. Flowering and fruiting hedges are best suited for informal plantings since they require minimal pruning. This way there is less chance of cutting off blooms and berries.

Boxwood is a popular choice for a formal clipped hedge and is easy to shape and maintain with judicious pruning at low or medium heights. At the Atlanta Botanical Garden, a formal boxwood hedge outlines beds in the rose garden. It provides important evergreen structure and softens the brick pavement. It also contains the informal plantings of roses and perennials like Mediterranean spurge, Euphorbia characias, and lamb's-ear.

For a large formal hedge, selections of evergreen holly such as American holly, Ilex opaca, and Burford holly, Ilex cornuta 'Burfordii', are popular choices. Another holly I really like for hedging is 'Mary Nell', with its rich dark green glossy leaves.

An evergreen that grows well in sun or partial shade and tolerates heat and drought is Carolina cherry laurel, Prunus caroliniana. Growing 20 to 30 feet high, it too is easy to maintain with pruning. The selection 'Bright 'n Tight' is denser and reaches only about 10 feet.

Also adaptable to sun or shade is small anise tree, Illicium parviflorum, with olive-green foliage. To maintain a natural look, use hand pruners instead of electric shears.

For a more formal look, inkberry holly, Ilex glabra, can be sheared as a hedge at 2 feet or taller. This native tolerates wet soils and grows in sun or shade.

For shady gardens, Canadian hemlock, Tsuga canadensis, makes an elegant needled evergreen hedge. While it can be sheared, it will keep a more stately look if individual shoots are removed each year.

In addition to beeches, a number of deciduous trees and shrubs are effective as hedges. One that tolerates severe pruning is the hedge maple, Acer campestre. Growing 30 to 35 feet or more, it offers handsome maple leaves that are dark green in summer and yellow in fall.

OTHER CHOICES

• European hornbeam, Carpinus betulus 'Fastigiata': This deciduous tree has a strongly architectural look.

• Pineapple guava, Feijoa sellowiana: Large multistemmed plant is mostly evergreen, with curious flowers in spring, with red tufts and white petals. Tolerates pruning well.

• Yaupon holly, Ilex vomitoria: Small-leaved evergreen is fast-growing and easy to shear.

• English laurel, Prunus laurocerasus: Dark green leaves 3 to 7 inches long and about 2 inches wide.

• Portuguese laurel, Prunus lusitanica: Densely branched, it grows to 10 to 20 feet.

• Hardy orange, Poncirus trifoliata: Deciduous shrub has polished green stems and fragrant orange fruits.

ERICA'S PICK

Mary Nell holly

Botanical name: Ilex 'Mary Nell'

About the plant: Glossy evergreen foliage with tiny spines and abundant red fruits. Can reach 10 to 20 feet high and 10 feet wide.

Use in the garden: Depending on how it's pruned, makes an effective formal or informal hedge and an elegant specimen.

Planting and care: Plant in full sun or part shade in well-drained soil.

Source: Ashe-Simpson Garden Center, 4961 Peachtree Industrial Blvd., Atlanta, 770-458-3224.