§ 154-20.04  Required Landscape Areas.
   (A)   Single-family residential requirements.
      (1)   Single-family residential landscape installations on lots equal to or greater than 5,000 square feet in size installed as part of new construction or remodel are subject to the standards set forth herein.
      (2)   A minimum of one 15-gallon shade or street tree is required within the front yard setback of all single-family residences and provided with a permanent irrigation system. Tree requirement must be fulfilled before the Certificate of Occupancy for the residence is issued.
         (a)   One saguaro cactus a minimum of eight feet in height or three 5-gallon ocotillo plants may be used as a substitute the tree requirement.
         (b)   The developer and/or homeowner may submit a signed and dated Agreement for Installation of Landscape prior to the issuance of the Certificate of Occupancy stating the tree will be installed within three months following the issuance of the Certificate of Occupancy.
      (3)   When the single-family residence is adjacent to a tree belt with a width of at least eight feet, a minimum of one street tree is required to be planted in the tree belt, and provided with a permanent irrigation system.
   (B)   Requirements for all other zoning districts. Required landscape is classified into four categories: perimeter, off-street parking, other areas, and retention basins, as outlined herein. Multiple categories can apply to one property or parcel.
      (1)   Perimeter.
         (a)   Streetscape zone (including all streets surrounding a subdivision). Abutting all public street rights-of-way shall be a streetscape zone maintained exclusively as landscape areas with vegetation and hardscape materials measured from the back of curb for the first 20 feet or until the vertical plane of the building, whichever is less. The streetscape zone shall be calculated regardless of public rights-of-way or setback delineations. In residential districts, the streetscape zone is required for all streets surrounding a subdivision and any non-residential uses within the subdivision.
   FIGURE 4: Streetscape Zone Examples
            1.   Trees. Street trees are required to be planted every 35 linear feet along the street right-of-way, as measured from the center of the trunk. Street trees shall be planted in accordance with the distribution and placement requirements of this article.
            2.   Shrubs. Along arterial and collector streets, shrubs are required at a rate of four per required tree, except in certain pedestrian-oriented streetscape zones where shrubs may be reduced.
            3.   Groundcover. For all landscape areas within the streetscape zone, colored landscape rock shall be used as top dressing. Vegetative groundcover is permitted, but not required. For any area to be dedicated to the City of Yuma, no vegetative groundcover is permitted, but artificial turf is allowed.
            4.   Building frontage/location.
               i.   If a building or structure is located ten feet or less from the back of curb, no trees are required and all areas located between the buildings and the back of curb must be either landscape or hardscape.
               ii.   If a building or structure is located at least ten feet from the back of curb, trees are required along that street right-of-way.
            5.   Special landscape treatment, may be required for Gateway and Historic/Scenic Routes as recommended in plans referenced in the General Plan.
         (b)   Medians. Median width is measured from the back of median curb to back of median curb. The minimum width for a landscaped median is eight feet.
            1.   Trees. Trees are allowed only in medians with a width of 15 feet or greater, shall be planted at a rate of one tree per 35 linear feet, and shall be located a minimum of five feet from the back of median curb. Species shall be selected from the Recommended Plants List as approved for medians. Trees shall be located so that the expected mature tree canopy does not ultimately extend into the street right-of-way. Maintenance access shall also be considered in relation to traffic movement.
            2.   Shrubs. Shrubs shall not be required for medians, but may be planted, with the approval from the city, within medians with a width of eight feet or greater. Mature size of the shrub shall be carefully considered to avoid eventual encroachment into the street.
            3.   Ground cover. Colored landscape rock shall be used as top dressing in all medians eight feet or wider. No vegetative ground cover or living grass is permitted, but artificial turf is allowed. Any portion of any median fewer than eight feet in width may be treated with stamped concrete or other approved inert material.
         (c)   Screening between zoning districts. Required screening setbacks between residential districts and adjacent uses shall provide sufficient screening in order to mitigate the effects of potential nuisances such as dirt, litter, noise, heat, and glare of lights. The screening shall be composed of plant material and, depending on the zoning district, a seven foot high solid masonry wall.
            1.   Trees. One per 35 feet (on center) of solid perimeter screening or subdivision wall; 15-gallon container (non-deciduous).
            2.   Shrubs. One shrub per eight linear feet on center.
            3.   Rear, service side, and/or loading docks. Shall be screened from view by a masonry screening wall seven feet in height.
            4.   Screen row. A screen row of 15-gallon trees (non-deciduous) planted 25 feet on center (or major fraction thereof), shall be provided along any lot line for a lot on which a residential structure greater than one-story in height is located with a lot line adjacent to any other residential structure.
      (2)   Off-street parking. Incorporating trees and shrubs in parking lots provides shade for people and cars, reduces the urban heat island effect, intercepts stormwater, improves aesthetics, improves air quality, provides visual screening, and creates a habitat for wildlife.
         (a)   Landscape within parking lots.
            1.   Trees. For parking lots with eight or more spaces, one shade tree is required for every eight spaces or major fraction thereof. Trees shall be evenly distributed within the parking lot in tree wells with a minimum of 50 square feet of pervious area, or, when tree wells are not possible, located within four feet of the perimeter of the parking lot. At a rate of one and a half per required tree, trees may be planted within five feet of the outer perimeter of the parking lot to meet this requirement. Trees required for other landscape areas cannot be double-counted to fulfill this requirement. Trees planted outside the perimeter of the off-street parking lot but intended to count towards the requirements for off-street parking areas shall be clearly identified as such on the plan. Required trees may be eliminated for spaces located directly under a covered parking canopy.
   FIGURE 5:  Parking Lot Design Options
         (b)   Screening for off- street parking. On the exterior edge of an off-street parking lot containing 15 or more spaces, a planting strip not less than five feet in width shall be provided parallel to any street rights-of-way and planted with shrubs as specified below to achieve 80% visual screening with a minimal height of three and one-half feet at maturity. This screening may also include walls, but in no case shall a structure or shrub be placed within any visibility triangle for driveways or streets.
            1.   Shrubs. Minimum of one per eight feet (on center) of parking lot adjacent to a public right-of-way.
      (3)   Other areas. All other areas of the site not specifically addressed in this section shall be landscaped. This includes all parts of a site not devoted to decks, patios, structures, driveway and/or parking improvements, lighting, sidewalks, signs, solid waste/recyclable materials collection and storage, and similar improvements.
         (a)   For any landscape area adjacent to the streetscape zone, inert groundcover is required as top dressing and shall match that used in the adjacent streetscape zone.
         (b)   Future building pads in development projects within the Transitional (TR), Limited Commercial (B-1) and General Commercial (B-2) Districts. Top dressing shall be inert groundcover, vegetative groundcover, or combination thereof. This helps control particulate matter (PM10) and improves aesthetics.
      (4)   Retention basins.
         (a)   General requirements.
            1.   Retention basis shall be designed, graded, and landscaped so as to aesthetically enhance the natural configuration of the area. Plantings located in the basin shall be adaptable to periods of submersion. Retention basins shall be shaped consistent with good landscape design standards as well as meeting the stormwater retention requirements of Chapter 192. Retention basins shall be designed in order to facilitate multiple uses of the basin whenever possible.
            2.   Graded slopes shall be designed to provide gentle, undulating contours (contour grading) and shall maintain an average slope of 4:1 and shall not exceed a slope of 3:1. Trees, shrubs, or vegetative groundcover shall not be planted on a slope greater than 4:1.
            3.   Trees and shrubs shall not be planted within 20 feet of inlets, outlets, or maintenance access ramps within any basin.
            4.   Gunite or concrete groundcover within retention basins shall be prohibited, except as necessary for the primary purpose of the basin and for walking paths. In all cases, the designed bottom elevation of the retention basin shall be a minimum of one-foot above the highest recorded ground water level.
            5.   Six-foot high wrought iron fences (designed to discourage climbing), or equivalent as approved by the Zoning Administrator, shall be installed around retention basins which have a designed water depth greater than three and one-half feet, and shall allow the basin to be visible at all times. Openings in the fence shall not allow the passage of a six-inch sphere. Any pedestrian gates shall be of a self-closing and self-latching type. In all cases, the requirements for the visibility triangle shall be applicable.
            6.   Rip rap is required at the inlets and outlets. Rip rap shall have filter fabric underneath.
            7.   Unless dedicated for use as a neighborhood park, basins dedicated to the City of Yuma shall not have grass and shall be planted with xeriscape plants chosen from the Recommended Plants List.
            8.   Major redesign of retention basins requires submittal of a landscape plan in accordance with § 154-20.06(B) and must comply with the stormwater retention requirements of Chapter 192.
         (b)   Requirements for retention basins by zoning district. Using Figure 6: Flexible Point System for Retention Basin Design, a project shall achieve a minimum number of points for each zoning district as indicated below. Choose at least one option from each category shown in Figure 6. These requirements apply only to basins not landscaped under another requirement set forth in this code. For any portion of the retention basin that is adjacent to a street, the landscape requirements for the streetscape zone shall be applicable in addition to the requirements of this section.
            1.   Residential zones.
               i.   Joint use retention basin/neighborhood park. Must earn a minimum of 50 points, be a minimum of five acres, with three acres of flat grass, and provide amenities. Must have approval from the Parks and Recreation Director to provide long-term maintenance or another funding mechanism for maintenance.
               ii.   Accessible basin. Must earn a minimum of 25 points. For residential subdivisions developed in multiple phases and as site planning constraints allow, the retention areas shall be co-located.
            2.   Commercial zones. Must earn a minimum of ten points. If a basin is adjacent to a collector or arterial roadway, it must earn an additional five points.
            3.   Industrial zones. Must earn a minimum of five points. If a basin is adjacent to a collector or arterial roadway, it must earn an additional five points.
            4.   Inaccessible Basins. In certain limited instances as determined by the Zoning Administrator, basins completely surrounded by a six foot or higher solid masonry wall shall be exempt from providing vegetation. Inert groundcover is required.
   FIGURE 6: Flexible Point System for Retention Basin Design
Trees & Shrubs
1 shade tree per 6000 SF of basin (except flat turf area) and 4 shrubs per tree
1 shade tree per 4000 SF of basin (except flat turf area) and 4 shrubs per tree
No grass
More than 30% of total area
More than 60% of the total area
More than 60% of total area to be a minimum of 3 acres with slope between 3-5% for recreational use
Landscape Rock
100% Yuma Grey
Minimum 30% colored landscape rock
100% colored landscape rock
1 boulder per 5000 SF of basin
Colored rip rap at inlets/outlets
Play area, natural/informal
Minimum 4’ wide concrete walking path traversing the basin
Minimum 4’ wide concrete walking path with a minimum length of 1000 linear feet
Pedestrian-scale lighting around walking path
Play structure
Basketball court
Creative Solutions
Parking islands designed to capture and filter stormwater
Bioretention facilities such as vegetated drainage swales or stormwater planters
Retention capacity under parking lots (if 100% undergroun d, this chart does not apply)
   FIGURE 7: Sample Design of Accessible Basin in Residential Zone
      (5)   Exceptions.
         (a)   Industrial lots larger than two acres. Industrial lots which have an area greater than two acres shall provide a total landscape area of 15% of the lot size or submit landscaping plans to the Zoning Administrator or designee (per § 154-20.06) in lieu of meeting the requirement to provide a total landscape area of 15% of the lot size. The Zoning Administrator or designee is authorized to approve landscaping plans that provide less than 15% of the lot size for industrial zoned property provided such plans meet the spirit and intent of the landscape code.
(Ord. O2010-32, passed 7-7-2010; Ord. O2014-06, passed 2-19-2014; Ord. O2017-024, passed 8-2-2017)