Most evergreen shrubs require well-drained and well-aerated soil to thrive. Clay soils are heavy, waterlogged and compacted. If you want to plant evergreens but have claylike soil, add an amendment, such as aged manure, sphagnum peat or compost. The Colorado State University Extension recommends adding 3 to 5 cubic yards of organic matter to every 1,000 square feet of clay soil. Work the matter down to at least 5 to 8 inches deep for the best results.
1 to 5 Feet
The Alexandrian or poet's laurel (Danae racemosa) grows between 2 and 3 feet tall with a similar spread. This slow-growing shrub is hardy to U.S. Department of Agriculture Plant Hardiness Zone 7b and prefers partial to full shade. The Alexandrian laurel has glossy, green foliage and produces orange-red fall berries. The tiny Silver Mist shore juniper (Juniperus conferta 'Silver Mist') only grows to 1-1/2 feet tall but spreads to 3 feet wide. This shrub thrives in heavy clay, as long as it's well drained. The shore juniper is hardy in zones 6 through 9. Plant it in sun to light shade.
6 to 10 Feet
True to its name, the glossy abelia (Abelia x grandiflora) has shiny, deep-green foliage. A semievergreen, this fast-growing shrub reaches heights up to 6 feet and produces an abundance of long-lasting, pink-to-white blossoms. Glossy abelia tolerates drought and is hardy to USDA zone 6. Plant glossy abelia in sun to partial shade. The Mexican orange (Choisya ternate) has glossy, dark-green leaves. This aromatic plant blooms with white flowers in spring and summer. Mexican orange shrubs grow up to 10 feet tall with a slightly narrower spread. They are hardy in zones 7 through 10 and tolerate light clay and sun to shade.
10 to 15 Feet
The Southern waxmyrtle (Myrica cerifera) grows to 15 feet tall with a 10-foot spread. This broadleaved plant has fragrant, glossy foliage. The Southern waxmyrtle is hardy to USDA zone 7b and tolerates drought, salt spray and deer, as well as a range of soil types from clay to sand. Plant Southern waxmyrtle in sun to partial shade. The O'Spring Chinese holly (Ilex cornuta 'O'Spring') grows 15 feet tall. This shrub thrives in zones 7 through 9 and prefers sun to light shade. The O'Spring Chinese holly has green-and-gold variegated foliage and tolerates heavy clay and heat.
More than 15 Feet
The golden threadleaf sawara cypress (Chamaecyparis pisifera 'Filifera Aurea') grows between 15 and 20 feet tall. A narrowleaf evergreen, this cypress has fine, golden-yellow foliage and produces little cones. Golden threadleaf sawara cypress shrubs are hardy to USDA zone 4 and thrive in full sun. The white cedar (Thuja occidentalis) tolerates clay and wet soils. This shrub can grow as a tree up to 50 feet tall, but is generally grown as a shrub between 20 and 30 feet tall. The white cedar has dark-green, scalelike leaves and is hardy to zone 3. The white cedar prefers full sun.