• Hemlock has a soft, flowing form.Comstock/Comstock/Getty Images
  
  Hemlock trees are native to North America and grow well in the northeast, eastern seaboard, Pacific northwest, and even the midwest. They are the most graceful of conifers, and can grow to 80 feet with a spread of 30 feet or more. Foliage is short, soft and delicate and many hemlock varieties produce tiny cones. Though many hemlock varieties will grow in Maryland's zone 6 and 7 climate, some will not. All require deep, well-drained soil and full sun to partial shade. Hemlocks also benefit from some shelter from other evergreens or taller, deciduous trees.
  
  

Canadian

• Canadian hemlock (Tsuga canadensis) is the most common variety of hemlock in the northeastern United States. Sargent hemlock is a smaller cultivar with a weeping form, much beloved by homeowners and landscapers for a medium-sized evergreen planting with a wide spread. Try Aurea compacta for a golden foliage to contrast with Sargent's green. Still other cultivars of Canadian hemlock can grow as tall as 50 feet or more. Don't prune these trees in Maryland if you can help it. Warm temperatures and high humidity can attract insects and disease to pruning wounds.
  
  

Chinese

• Chinese hemlock (Tsuga chinensis) grows well in zones 5 to 7, making it a nearly perfect match with Maryland's climate. The only place this evergreen will struggle is in coastal areas because it doesn't deal well with salt spray. It can grow to a height of more than 40 feet and plantings should be placed 30 feet apart to avoid overcrowding. Be careful not to overwater Chinese hemlock which likes to dry out between waterings.
  
  

Japanese

• Japanese hemlock (Tsuga diversifolia) grows well in Maryland, and can reach a height of 40 feet or more. Its bronze-green foliage likes slightly acidic soil so you may want to amend planting areas with peat and sulphur before planting. Japanese hemlock has a pyramidal shape and produces many tiny cones in fall. It's also hardy to zone 5 and reliable in Maryland. Foliage is bright green in early spring and summer, turning darker in autumn and winter.