Landscaping in the District of Columbia is usually a small yard, a tree box, or a sloped lot under mature trees. Rowhouse gardens are narrow, shaded, and fenced by brick. Water from a downspout has a short path to a basement or an alley. Houses above the Potomac and along Rock Creek deal with slope, shade, and runoff from the hill behind them. If water moves toward the house, say that before you talk about plants.
Shade and reflected heat off brick are the design constraints on a row. Grass gives up. Ivy holds damp against masonry. A single tree can own the whole court and the gutter. On the wooded edges the work is limbs, leaves, and erosion on a slope, not a weekly pass with a mower over a broad lawn. Describe the space honestly: a rear court, a front strip, a hillside, or almost no soil.
Drainage is fussy. Alleys may sit higher than the back door. A neighbor grade can send water along a party wall. A clogged areaway at an English basement will flood a room that a suburban swale would have saved. Grading you can still do is small, and it still matters. Retaining walls on the Palisades side and similar slopes are part of the yard when they lean. Say so.
Planting has to live in shade or in heat bouncing off brick, depending on the block. Tree work has to keep limbs off roofs and wires in tight quarters. Debris leaves through an alley or down a sidewalk, not through a wide side gate. Irrigation, if any, should not soak a foundation and needs a shutdown before a freeze. Do not describe a District court as a suburban acre.
Walk the back step, the areaway, and the downspout. Landscaping in the District of Columbia should keep water out of the basement and make a small or a sloped yard usable. Call the number on this page.