I would like to plant a hedgerow of evergreens 6 to 20 feet high, any...
You did not mention the site - sun or shade and if deer are a problem. Consider planting a mixed screen so that you do not lose the stand to an insect or disease. You can send us additional information.
Also, See our publications on native plants of MD http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/HG120_NativePlantsof... and deer resistant ornamentals http://extension.umd.edu/sites/default/files/_images/programs/hgic/Publications/non_HGIC_FS/FS655.pd...
thank you for the reply, the site is full sun, no major deer issues. soil seems average, nearby vegetation includes figs, white pine, maples, walnut and yews. thanks again for the reply.
Emerald Green Arborvitaes would be useful as a screen. This type of arborvitae grows to about 12-14 feet.
As mentioned above, you could plant a varied line of trees and shrubs, which would protect you from losing the whole line were a pest or disease to arise.
You could mix in hollies, and if you have room even add some other deciduous berrying plants like viburnum, nandina domestica or spring bloomers like crabapples in front.