Fosters holly (Photo by Maile Neel)

After you move into your new house and begin to think about selecting some trees for your yard, you may find this more challenging than you expect.

First, the neighbors may be closer than you realized when you chose a lot on an empty street with no houses on it, and this may change your tree-planting ideas altogether. A privacy screen of small evergreens for the side yards — a feature you had never considered — may become the first priority, with shade and ornamental trees to be planted later.

How could the proximity of the neighbors come as a surprise? The average lot size for a new house in the Washington area is a generous 7,200 square feet, with a width of 60 feet. But the houses built on these lots are big, occupying about 40 feet of that width. This leaves only about 10 feet for each side yard and 20 feet between you and your neighbors, said Dan Fulton of John Burns Real Estate Consulting in Reston, who has studied the Washington housing market for more than two decades.

The second challenge: You can’t just go down to the big box store nursery and select a good screening tree. In a new-home community, you have to do some fact checking first.

The local homeowners association (HOA) may have rules on your landscaping choices, dictating not only acceptable tree species but also the height in some instances, including that of a “living fence” between side yards, said Rockville lawyer Thomas Schild, who represents condominium and homeowners associations in the Washington area. Most HOAs in Maryland and Virginia do not address this, but some do. For this reason, homeowners should check the HOA documents before developing any landscaping plans, he said.

You’ll also have to locate the swales on your property because you can’t plant trees or shrubs in them. A swale is a shallow ditch. In new home communities, they run across individual lots channeling rainwater into the storm sewer system. Swales are often so shallow that homeowners have no idea they are there, especially when the grading is so subtle the yard appears to be essentially flat. Despite its near invisibility, a swale serves a critical function. Legally you cannot plant anything in it that will impede the flow of water or affect a neighboring property.

The location of the swales will be indicated on the site plan of your lot, which your builder included in the documents he submitted to get a building permit for your house. If your builder is still active in your community, you should be able to get this information from his sales agent or someone in his construction trailer. If not, you may have to go the office where your builder applied for a permit to get a copy of your site plan.

Once you get the site plan and study it, you’re likely to discover that a swale runs along one or both of your side-yard property lines (half of it is on your side and half on your neighbor’s), exactly where you envisioned a “living fence” of screening trees. You may still be able to implement this plan if the swale is narrow enough, said Jim Baish, a Frederick landscape architect and land planner who has designed the land-use plan for many new-home communities in the Washington area. For example, a 5-foot-wide swale down the middle of the 20-foot-wide area between houses would leave you 71 / 2 feet to work with, enough room for a row of small evergreens, he said.

Your site plan may also indicate a utility easement running across your front yard where underground lines for electricity, gas, cable and phone are buried, Baish said. The easement can be as wide as 15 feet from the curb toward your house; inside this area, a utility has the right to remove a tree if its roots are causing a problem. This is far less likely if you contact “Miss Utility,” a local service (District and Maryland, 800-257-7777; Virginia, 800-552-7001) that arranges for each utility to come and locate its lines, usually by spraying a different stripe across your lawn, so that you can factor this into your tree-planting decisions.

When you’re finally ready to start selecting trees, you’ll discover that much of the advice has changed since you bought a tree for your old house 20 years ago. Back then, the emphasis was on ornamentals and bigger trees that looked good and were easy to maintain. The easy-to-maintain part is still true, but ecological and environmental considerations are the new starting point.

Today, local foresters and horticulturists urge homeowners to favor native tree species wherever possible because they have a much higher tolerance for Washington’s cold winters, hot and occasionally dry summers, and changing climate. Urban forester Samantha Wangsgard of Fairfax County’s Urban Forest Management Division said her office also urges homeowners to pass on widely planted native species such as the red maple and consider less familiar ones such as the swamp white oak. A neighborhood with too many of the same tree can quickly become denuded if those trees become diseased, she said.

At the same time, the experts also said that sometimes a nonnative is your best option. For example, the flowering dogwood, whose blossoms are the state flower of Virginia, is susceptible to a debilitating fungus. Wangsgard said her office now recommends the hardier Appalachian spring dogwood, a cultivar that was developed in Maryland to be more disease resistant. It’s a pretty seamless substitution, she added, because the cultivar’s blossoms so closely resemble Virginia’s state flower that only an expert will notice the difference.

In many new home communities in the outlying suburbs, another desirable trait in a tree species is leaves that are distasteful to deer. Sterling horticulturalist Josh Kane has found that deer do, in fact, have preferences, avoiding some evergreens, including the native eastern red cedar and the nonnative arborvitae family. But Kane was quick to add that nothing is completely deer proof. In harsh winters like the one we just experienced, Kane said, “deer ate everything. If deer could eat it, they were eating it.”

Some issues with tree planting are the same as they have always been, new house or not. Many homeowners grossly underestimate the eventual size of a small, 1-inch-diameter “starter” tree and plant it too close to their house. Ten or 15 years later, when the tree’s branches are pushing up against windows or stopping up gutters, it will have to be removed.

Such a costly mistake can be avoided if you put your trees in spots that can accommodate them at maturity. If a tree may reach a height of 50 feet, you need to plant it in a spot that will accommodate both the canopy of such a big tree (a circle with a diameter equal to the tree’s height at maturity, in this case 50 feet) and its root system, which will eventually occupy about the same sized area. To keep a 50-foot tree from hitting your house, it should be planted 20 to 25 feet away, Wangsgard said.

This means that you’ll have to shelve your ideas about a large, sheltering shade tree for your front yard because it will be too shallow. For a typical 60-by-120-foot lot, there’s only 20 to 25 feet from the curb to the house. But you could put a large shade tree in your back yard, which is typically 55 feet deep for this size of lot.

When you factor in all these considerations, what trees are good candidates for your new yard?

The most suitable tree for a privacy screen along your side yard is the nonnative arborvitae, a cylindrically shaped evergreen with scale-like leaves instead of needles. There are more than a 100 varieties of arborvitae. Wangsgard said the two her office recommends — the dark green American arborvitae and the Columnar oriental arborvitae — do well in the Washington area. In addition, both do well in wet soil, a periodic circumstance if you plant them next to a swale.

On the downside, each one can grow as high as 30 feet, and they require pruning. The emerald green arborvitae, which Baish has recommended, does not grow as tall but still requires pruning. The maintenance required with an arborvitae may sound onerous, but Baish said it’s fairly easy because with arborvitae you can do the pruning with electric shears.

Because the arborvitae is so widely planted, Wangsgard suggested intermixing it with Foster’s holly or Nellie Stevens holly, both nonnatives that will require periodic pruning that can also be done with electric shears.

Though the neighbors at the back will be farther away than the ones to the sides of your new house (with a typical backyard depth of 55 feet, the neighbor’s house directly behind you would be 110 feet away), you may want some privacy screening around your back yard to create an additional private outdoor living area that you can use during the warmer months. Two native species that Wangsgard recommended are the eastern red cedar (which looks like a large juniper bush) and American holly. Both of these can reach a height of 30 to 40 feet, so you should plant them at least 10 feet inside your lot line.

You will certainly want to plant some shade trees in the front, and there are plenty of choices that are appropriate for a smaller front yard in a typically sized suburban yard of a new house. The downey serviceberry, the Allegheny serviceberry and the eastern redbud are three hardy native species that reach a height of only about 20 feet, Wangsgard said. And if you hanker for dogwood, there’s the nonnative Appalachian spring.

Back yard
A 55-by-60-foot back yard of a typical suburban lot could accommodate one majestic shade tree that could eventually exceed 50 feet in height, such as the aforementioned native swamp white oak or the native sycamore. You could also consider smaller native shade trees whose mature height will be somewhere between 25 and 50 feet, including the river birch and the persimmon, Wangsgard said.

For a comprehensive list of recommended trees species for this area, which includes helpful information on native species, projected tree canopy and environmental tolerances, go to
. The most helpful information is on pages 65 to 78.