Question
QUESTION: We have a very open backyard and would like to put up some tall evergreen type of shrubs/trees along the 25 foot border between our neighbor.  We don't want anything that sheds or trees that will grow taller than about 20 feet.  We were looking at Emeral Green Arbor vitae but have concerns that with moderate snow the branches fall apart. We're in Potomac, MD right outside of Washington, DC.  Thank you!

ANSWER: You are in a USDA Zone 7 (same as me).  

The Arborvitae will get up to 15 feet tall, and more open as time goes on.  Snow isn't so mush a concern, unless you plant it right under the eves of a house where the snow can crush it.  Our problem with it is that it needs fertilizing year-round, or it will get yellowish looking - we have dry winters & hot, dry summers...Maryland is actually better suited for it.

If you are in no "hurry" for your screen/hedge to fill in, you can try a slower-growing hedge evergreen, the English Yew (Taxus species). It can take a snowdrift better, too.

Also consider the Eastern Redcedar (Juniperus virginiana), or if you don't have too much wind, the Leyland Cyprus (x Cupressocyparis Leylandii), but both of these will get a whispy 20' tall, if untrimmed.  

Holly (Ilex species) is also an effective evergreen hedge. These will get from 6-12 feet tall. Cotoneaster is also a "low-maintenace" & informal hedge plant - C. lucidus and C. divaricatus, grow to 6 - 10' & 5 - 6' respectively.

Hope it helps.  ~M

---------- FOLLOW-UP ----------

QUESTION: Thanks so much for your response.  The other option we were looking at is the japanese privet but I don't know much about it- pros/cons?   Thanks,
Caroline

Answer
Japanese Privet (Ligustrum japonicum) is marginal in your area...it does best in USDA Zone 9 and warmer, but can survive in Maryland, if protected from harsh winter weather.  It is more of an open shrub/small tree when its at full maturity, but if you "hedge" it, the result is a more compact plant.

Considered a noxious weed in the southern forests.

More info on it: http://ag.arizona.edu/pima/gardening/aridplants/Ligustrum_japonicum.html

~M