Landscaping in Pittsburgh is a slope with a house in it. Steps instead of a path, a retaining wall, a terrace of lawn, and beds cut into the hill. Water runs at the uphill foundation unless the grade says otherwise. A wall that leans is not a planting detail. It is the thing that is holding the yard off the porch. Valley humidity grows things fast. Winter buries them, then the thaw tests every downspout you aimed casually at the slope.
Drainage is the project. Leaders that discharge on frozen ground, soil against the siding on the buried side, and a patio that sends water at a walk-out door will keep the lower level wet. Say where rain goes. Regrading on a hill is not the same as raking a flat yard. It can move water onto a neighbor below you or into your own foundation. Say who is downhill. Irrigation has to be winterized or the first hard freeze splits it. Many of these lots need the water carried away more than they need more of it.
Trees on a slope above a roof drop limbs and hold shade on the wall that is already damp. A tree below the house is a different problem from a tree throwing leaves into a gutter you can only reach by steps. Salt on public steps burns the edge of whatever you plant there. A weekly mow on a terraced lawn is real work and a short season. Say if the yard is too steep to mow safely. That is a design fact, not a complaint.
Describe the lot as uphill, downhill, or both. Say whether a wall is involved. Say whether material can be wheeled in or must be carried on city steps. If the lower level takes water, lead with that. Plant lists wait. If you only have a strip between the sidewalk and a retaining wall, say strip. Do not order a meadow.
There is no flat alley behind a party wall unless you happen to live on one of the level streets. Landscaping in Pittsburgh is the hill, the wall, and the water running down it. Call the number on this page.