Landscaping and plantings serve to screen, define, and highlight framing views and giving form to space. Landscaping is an integral part of any development.
1. 
Well-designed landscaped areas should be maximized and balanced throughout the site.
2. 
Native trees and shrub plantings should be grouped together to create strong accent points within the site. Trees having greater than eighteen-inch (18") caliper are considered important. It is strongly recommended that they be preserved to the greatest extent possible.
3. 
Dense landscaping and/or architectural treatments should be provided to screen unattractive views and features such as storage areas, trash enclosures, transformers, generators and other similar elements.
4. 
Electrical transformers, which are installed as part of a new project, should be located to the rear of the site, or underground. Existing transformers, located at the front of the site, should be screened by substantial dense landscaping and/or architectural barrier.
5. 
The incorporation of defined outdoor spaces into the buildings and site designs of all new developments is encouraged. Outdoor spaces that are encouraged include terraces, courtyards, patios, covered walkways, passages, gardens, and trellised areas.
1. 
All plant materials should be sized so that landscaping has a full and finished appearance at the time of planting and a mature appearance within two (2) years of planting.
2. 
Unless unusual circumstances prevail, all parking lot trees should be a minimum of two-inch (2") caliper. Street trees or perimeter trees should be minimum two-inch to three-inch (2"-3") caliper. In other areas proposed trees should meet the following standards.
3. 
Evergreen trees six-foot (6') minimum height.
4. 
In cases where existing highly protected trees over eighteen-inch (18") caliper are removed for new development, substantial replacement trees and additional landscaping material in new locations is strongly encouraged.
5. 
No irrigated landscape area should be placed under protected trees.
6. 
All proposed shrubs, except seasonal annuals, or ground covers planting should be a minimum of eighteen inches (18") mature height. Shrubs and ground cover plants should be spaced close enough together to ensure an attractive and mature planting effect.
7. 
For screening in car parking areas, a minimum of thirty-six-inch (36") mature height is recommended. For other screening purposes a minimum of seventy-two-inch (72") height is recommended and should include various evergreen material.
8. 
Landscaping connections linking open spaces/woodlands and meadows should be made wherever possible.
9. 
Bike paths and pedestrian pathways linking neighborhoods and business areas are encouraged and should be subtly landscaped with native plant materials that require minimal care.
10. 
Native plant species should be chosen for all landscaping projects in Portsmouth, because they grow well in the climate and soil conditions of the area without requiring excessive irrigation.
Perimeter trees are planted along roadways or between parcels. (The recommended Perimeter Tree List is included as Appendix II.[1])
1. 
Trees may be recommended in the public right-of-way for all development within non-residential districts. The Recommended Tree List (Appendix II) designates recommended tree species for each street. New trees should be planted consistent with the plan and the perimeter tree standards and guidelines.
2. 
In commercial areas, perimeter trees are recommended in addition to any proposed on-site landscaping to provide the shading, visual enhancement and continuity for the streetscape.
3. 
Perimeter trees should normally be planted at forty-foot (40') intervals.
4. 
Any existing perimeter tree that constitutes a specimen, historic or protected, may be substituted for a recommended perimeter tree.
5. 
Perimeter tree placement should include consideration for vehicle line of sight, entrance and exit curb cuts, street light and traffic control devices, and other site specific conditions as part of design review process.
6. 
Plant materials and perimeter trees should be installed consistent with planting standards which specify soil depth, irrigation requirements, tree grates, staking and other planting details.
7. 
Where significant vistas or view corridors are present or desired, the number and placement of the perimeter trees and landscaping recommendations may be amended.
[1]
Editor's Note: Appendix II is included as an attachment to this chapter.)
1. 
Landscaping plans should show all obstructions such as street lights, meters, backflow devices, utility covers, transformers, and similar objects which may affect plant placement and installation limitations.
2. 
When constructing new landscape planting areas on surfaces which were previously covered by pavement or structures, all existing asphalt, base rock or other deleterious material should be removed to the depth of the native soil and clean soil should be used to backfill the planting area.
3. 
All exposed dirt areas should be covered with bark mulch or other weed control measures included as part of final landscape installation.