A. 
Selection and Installation. The selection of landscape plant materials from the "Landscape Development Guide" is encouraged. This guide is available from the Planning Department and amended from time to time. All plant material shall be selected and installed in conformance with current American Association of Nurserymen standards.
B. 
Size Requirements, General.
1. 
Street Trees. All trees planted adjacent to streets or in street right(s)-of-way shall be located in accordance with the City of Mountlake Terrace roadway standards. Street trees are to be spaced an average distance of 35 feet on center or as specified in adopted design standards for specific zoning districts, with the Engineer making a final determination of location based on specific site and frontage conditions. Deciduous street trees shall have a minimum caliper of two inches measured six inches above ground level and have a clear trunk for at least six feet above grade. Evergreen street trees shall be a minimum of 10 feet in height and planted well outside any required sight area triangle, spaced a maximum of 30 feet on center.
2. 
Trees, Other. Deciduous or broad leaf evergreen trees shall have a minimum caliper of one and one-half inches measured six inches above ground level. Evergreen trees shall be a minimum of six feet in height. All trees shall be set back a minimum of three feet from the face of any curb, sidewalk, building, or other structure.
3. 
Shrubs. Shrubs shall be selected to provide variety in height and texture, enhance the architectural design, and attractively screen views of parked vehicles and noncompatible site land uses. Installed shrubs shall have a minimum height of 21 inches. Depending on variety and intended use, other shrub stock sizes may be allowed or required.
4. 
Ground Cover. Living ground cover, other than grass, shall be installed so that it meets the coverage requirement of the applicable landscaping type (MTMC § 19.130.240). Spacing shall be sufficient to achieve 75 percent ground coverage in a three-year period as designed by a certified landscape specialist, or according to the following standard:
a. 
Two-inch pots: 12 inches on center (o.c.);
b. 
Four-inch pots: 18 inches o.c.;
c. 
One-gallon container: 30 inches o.c.
5. 
Lawn Grasses and Low Impact Development Native Seed. Coverage shall be provided with either seed or sod. Seed must germinate and demonstrate 100 percent coverage, or coverage in accordance with native seed manufacturer specifications, prior to final acceptance of such landscaped areas.
(Ord. 2074 § 8.3(A), 1995; Ord. 2702 § 2, 2016; Ord. 2729 § 20, 2018)
A. 
General. An approved irrigation system with an automatic time clock activating mechanism shall be installed for all landscaped and turf areas in any multi-household project containing five or more units, any planned unit development (PUD), and developments in any district which require more than 10 parking stalls.
All other projects shall provide sufficient hose bibs or quick couplers on site located such that any portion of the project site is within 75 feet of a hose bib or quick coupler.
An irrigation system installed for any other development or for a single-household residence shall provide an acceptable backflow prevention device. A plumbing permit is required for the installation and inspection of the backflow prevention device.
B. 
Irrigation Plan Requirements. An irrigation plan, drawn to the same scale as the landscape development plan, shall be submitted which contains, as a minimum, the following information:
1. 
Size and location of water meter(s);
2. 
Static water pressure from City's water main;
3. 
Service line type, size, and length;
4. 
Type and location of drain(s), coupler(s), shut-off and control valve(s), controller(s), and backflow prevention device(s);
5. 
Spacial layout of piping;
6. 
Main and lateral pipe size(s) and type(s);
7. 
Performance chart showing type, series, and hydraulic characteristics of sprinkler heads;
8. 
Hydraulic circuit analysis chart showing volume flow per valve.
C. 
Performance and Inspections.
1. 
The irrigation system layout shall reflect good design principles, minimize water usage and waste, and meet the watering needs of the specific plant materials used. Coverage shall be 100 percent or head-to-head coverage.
2. 
Minimum depth of burial for piping shall be 18 inches for main line(s) and 12 inches for all lateral line(s).
3. 
Two on-site inspections will be conducted to assure compliance with approved plans and adequate performance.
a. 
The first inspection will concern itself with adequate depth of burial for piping, pipe sizing, and system layout as designated on approved plans.
b. 
The second inspection will be a performance test for coverage with recommended changes and adjustments to be completed before final approval.
4. 
An electrical inspection of irrigation wiring by the Building Department is required.
5. 
The owner shall be responsible to have all backflow prevention devices and double check valve assemblies inspected and tested by a certified backflow device tester or cross-connection control specialist at the time of initial installation, whenever the device is repaired, and at least once a year. A copy of the report shall be submitted to the City. The device shall be repaired, overhauled, or replaced whenever found to be defective.
(Ord. 2074 § 8.3(B), 1995)
Landscape development may include gently mounded areas with a maximum slope of three to one and a preferred slope of four to one. All mounds and berms must meet Engineering Details and Specifications for grading. Slopes of mounds and berms shall blend into the adjacent terrain, unless stabilized by a retaining wall or curbing.
(Ord. 2074 § 8.3(C), 1995; Ord. 2792 § 22, 2021)