Don't know where you are in MD, but drive around the Beltway to Behnke's in Beltsville or to the newer Behnke's on River Road in Potomac. If they don't have it - or can't tell you everything you need to know about it - you don't need it.

Can't speak for evergreens in your zone because here in mine the only evergreens would be some of the boxwoods that can survive our climate as well as a whole host of conifers. And how far out from the foundation depends on what you're putting in. Low maintenance sometimes depends on how much ongoing work you're actually willing to put into the project to keep it looking decent.

How low is low with your windows?

Use the search feature here on the main page and look up all the previous threads on foundation planting.

When a tag or other information gives a "mature size" for a shrub or tree, it's generally the expected size at 10 years (that's 10 years from the time it sprouted from seed or was grafted, not ten years after you bought it). In some cases, you would be pruning to keep it smaller.

When figuring out how far from the foundation to plant, there are multiple things to keep in mind:

= You'll want to be able to access the outside of the house (for window-cleaning and other maintenance, as well as to care for the shrub). So plan on keeping at least a foot of space between the shrub and the house -- not when you plant it; you'll be planting it farther from the house.

= Dividing the shrub's mature size by 10 will give you the height and width the shrub will grow each year (if not pruned, and in average conditions). This will help you figure out how far from the foundation to plant the shrub.

= You don't have to keep the same shrubs forever. When they get too large, you can tear them out and put in smaller ones.

It's important to know how much sun the area will receive. Some evergreens won't care where they're planted, others will do poorly if receiving too much or too little sun.

My windows are low; about 6 inches off the ground, but they're huge. I can block the lower portion and still get plenty of light.

I'm on the Baltimore county/city line, which is either zone 6 or 7, I wish I could figure it out.

My house faces southwest, so my front yard is basically in sun all day starting from about 11am.

What about perennials that keep some green foliage during the winter months if evergreens won't work? Any suggestions?

You can put in your zip code here and find your USDA zone. This is the 1990 zone map.
http://www.garden.org/zipzone/index.php

The Arbor Day folks made an updated map in 2006. It takes global warming into consideration -- but doesn't divide the zones into A and B. You can use your zip code here also:
http://www.arborday.org/treeinfo/zonelookup.cfm

Both of these maps will tell you what winter minimums to expect (though no map is perfect, and every so often the weather will be seriously abnormal).

If you don't mind shrubs that are 12-18" or so, you'll have more of a choice. You can search here for some ideas (sometimes a search will yield no results; just go back and change the terms a bit).
http://www.mobot.org/gardeninghelp/plantfinder/Search.asp

For lower evergreens that do well in sun, consider some of the shortest heathers or heaths (there are varieties that bloom at all different times of the year, in tones of white-pink-red-purple; some very odd foliage colors too, if you like that sort of thing). I think the shortest of mine that I would recommend is Springwood White (8"). You can dispense with pruning if you don't mind them growing together (my parents prune their slightly taller heaths once a year into neat cushions), but they'll need regular watering or a few will suddenly die on you. Try these mail order vendors, if you don't find anything locally:
http://www.heathsandheathers.com/hhweb_001.htm
http://www.sylvannursery.com/index.html

Much easier to find are the lowest prostrate junipers (4-8"); they come in blue, green, and gold shades. Very slow to spread, but it's worth the wait.

Thanks, MissingObvious! (I'm zone 7, according to the zip code finder)

Conifers should do well in your situation and there are many that are arching/spreading and you could do a lovely selection - junipers, chamaecyparis, low pines, cultivars of spruce or fir; they come in different colours from blue to gold and many grow slowly. Your nursery is the best place to select; we can recommend till we're blue but if you can't get it locally there's no point. Avoid the big box store and maybe check out the places that Duluth recommended. You could also ask on the conifers forum for other places to shop.

You might enjoy punctuating the selection with some tall narrow forms too, especially out further from the window.

Perennials or ferns described as evergreen are often ratty looking. Probably best if they are fully herbaceous.

Don't make the mistake of designing your foundation planting independent of the whole yard. Maybe design the whole yard first before you decide whether you need foundation planting at all. You can post a photo here of your yard if you want some input on that sort of thing.

KarinL