18.105.030 Minimum vegetation and ground cover.
A. Minimum number of trees and shrubs acceptable per 1,000 square feet of landscaped area:
1. One tree, minimum two-inch caliper.
2. Four five-gallon shrubs or accent plants.
B. Minimum Percentage Ground Cover. All landscaped area, whether or not required, that is not planted with trees and shrubs, or covered with nonplant material as defined in subsection (C) of this section, shall have ground cover plants that are sized and spaced to achieve 75 percent coverage of the area not covered by shrubs and tree canopy unless a xeriscape plan is approved.
C. Landscape Materials. Permitted landscape materials include trees, shrubs, ground cover plants, nonplant ground covers, and outdoor hardscape features, as described below. “Coverage” is based on the projected size of the plants at maturity, i.e., typically three or more years after planting. The landscape materials below may be modified as part of an approved xeriscape plan.
1. Existing Vegetation. Existing noninvasive vegetation may be used in meeting landscape requirements.
2. Plant Selection. A combination of deciduous and evergreen trees, shrubs, and ground covers shall be used for all planted areas, the selection of which shall be based on local climate, soil, exposure, water availability, and drainage conditions. Applicants are encouraged to select native plants which are drought tolerant to reduce the demand on the city’s water supply.
3. Plant Establishment. Unless a certified landscape architect specifically recommends otherwise, all new landscaping shall be irrigated for a minimum of two years to ensure viability.
4. Soil Amendment. When new vegetation (including sod) is planted, topsoil shall be added and/or soils amended or aerated as necessary, to allow for healthy plant growth. Compaction of the planting area shall be minimized whenever practical and compacted soils shall be amended and/or aerated as necessary prior to planting.
5. “Invasive” plants shall be removed during site development and the planting of new invasive species is prohibited. Lists of locally invasive species are available through the local USDA extension office.
6. Hardscape Features. May cover up to 10 percent of the required landscape area (unless a xeriscape plan is approved); except in the downtown area where publicly accessible hardscape features may cover up to 80 percent of the required landscape area, subject to approval through site development plan review. Swimming pools, sports courts, and similar active recreation facilities, as well as paving for parking and access, may not be counted toward fulfilling the landscape requirement.
7. Nonplant Ground Covers. Bark dust, chips, aggregate, or other nonplant ground covers may be used, but shall cover no more than 25 percent of the area to be landscaped and shall be confined to areas underneath plants. Nonplant ground covers cannot be a substitute for ground cover plants unless approved as part of a xeriscape plan. [Ord. 966 § 2 (Exh. B), 2021; Ord. 918 § 2 (Exh. A), 2016; Ord. 817 § 8-3J.430, 2006.]