19.35.055 Plant specifications.
Unless otherwise specified, the following standards shall apply to all areas which are required to be landscaped by this chapter:
A. Trees. Trees to be planted under overhead electric power lines shall be species recommended in Snohomish County PUD No. l’s Tree Book, Puget Sound Energy’s Energy Landscaping or an alternative approved by the planning director. If the species planted is expected to be less than twenty feet high at maturity, the planning director may require that additional trees be planted. Trees that do not meet these standards, such as palm trees and Thuja occidentalis “emerald green,” may only be permitted for a portion of the landscaping through the modification process in EMC 19.35.190 when the proposal includes equal or better design quality, and increases the number of trees provided.
The planning director may modify the size of street trees required by this title when trees must be located in aboveground planters due to the location of underground utilities or other underground features.
1. Required deciduous trees shall be at least two inches caliper at the time of planting. If the species planted is expected to be less than twenty feet high at maturity, the planning director may require that additional trees be planted.
2. Required evergreen trees shall be at least six feet high at the time of planting. If the species planted is less than twenty feet high at maturity, the planning director may require that additional trees be planted.
B. Shrubs. Required shrubs shall be at least two-gallon size and at least eighteen inches high at the time of planting except if used for Type I landscaping.
C. Ground Covers.
1. Ground cover includes low-growing, living plant materials such as perennials, grass, low-growing shrubs, and similar plants. For purposes of this title, chipped wood, bark, similar mulching materials or nonliving artificial plant materials are not acceptable substitutes for required ground cover, except that in portions of LID stormwater facilities that count toward required landscaping, no more than twenty-five percent of the required ground cover may be in rock and mulch.
2. In order to accomplish ninety percent coverage of bare soil by ground cover within three years, spacing for ground cover shall be as follows:
a. Two-and-one-half-inch pots: twelve inches on center;
b. Four-inch pots: eighteen inches on center;
c. One-gallon pots: twenty-four inches on center;
d. Alternative spacing of particular species may be approved by the city if documentation concerning the effectiveness of the ground cover is submitted with the landscape plan.
D. Plant Materials, Size, Characteristics. All plant materials, sizes and characteristics shall be in accordance with the current American Standards for Nursery Stock.
1. See the city’s recommended tree list for recommended species.
2. The use of plant species native to the Pacific Northwest is encouraged.
3. Species listed in Snohomish County’s noxious weeds lists (Classes A, B and C) are prohibited and shall be eradicated or controlled when present. Invasive species such as English ivy cultivars “Baltica,” “California,” “Pittsburgh,” and Star, Atlantic ivy, and Scotch broom shall not be planted.
4. See the city’s stormwater regulations for additional standards for plantings in stormwater facilities. (Ord. 3774-20 § 9 (Exh. 7), 2020; Ord. 3322-13 § 6, 2013; Ord. 2657-02 § 33, 2002; Ord. 1671-89, 1989. Formerly 19.35.110.)