12.18.140 Plant materials and sizes.
A. The community development director shall adopt a list of plant materials which may be used to comply with the provisions of this chapter. A copy of this plant list will be available for inspection and copying in the department of community development during regular business hours.
B. The applicant may use plant materials on the adopted plant list or other plant materials as approved by the city. The city may require the applicant to modify the plant choice to:
1. Provide a desired diversity of species;
2. Make the plantings more in scale and compatible with the uses in the immediate vicinity of the subject property;
3. Provide plant materials which will fulfill buffering or landscaping purposes on a year-round basis;
4. Provide Pacific Northwest indigenous plant species, particularly drought resistant species that minimize water, maintenance, and fertilizer requirements.
C. Nonvegetative material shall not be considered a substitute for plant material. Bark, mulch, gravel, or other nonvegetative material shall only be used in conjunction with landscaping to assist vegetative growth, retain soil moisture, and assist in maintenance.
D. Plant sizes, excluding Type VI landscaping, shall be as follows:
1. Evergreen trees shall be a minimum height of six feet above finished grade, except that evergreen trees in Type I/II landscaping shall be a minimum height of 10 feet above finished grade.
2. Deciduous trees in street frontage landscaping, the Bothell boulevard system and Type II landscaping areas shall be at least two and one-half inches in diameter measured six inches above grade. All other deciduous trees shall be at least one and one-half inches in diameter measured six inches above grade. Where sight distance needs to be maintained, deciduous trees shall have a clear trunk area of at least eight feet above the ground.
3. All shrubs shall be at least 21 inches in height above finished grade and spaced at maximum three feet on center. Dwarf varieties or others approved by the department of community development may be installed at smaller heights and spacing. Varieties significantly larger than 21 inches in height may be installed at greater heights and spacing subject to approval by the community development director.
4. Ground cover spacing for one gallon plantings shall be 18 inches on center maximum or four-inch pots planted at maximum 12 inches on center.
5. Shrubs and ground cover shall provide an immediate surface coverage of at least 50 percent with an 85 percent coverage within two years.
E. Those developments where reduced landscaping is approved, pursuant to BMC 12.18.150, may be required to install street trees utilizing tree pits. Tree pits shall be a minimum of four feet by four feet depending on size potential of the tree.
F. All plant materials shall conform to the standards of the American Association of Nurserymen.
G. Street trees installed along residential local access streets shall be chosen from the following list:
Red Maple (Non-columnar) (Acer rubrum)
Norway Maple (Acer platanoides)
Redmond Linden (Tilia americana ‘Redmond’)
Zelkova (Zelkova serrata)
English Oak (Quercus robor)
White Oak (Quercus alba)
Katsura tree (Katsura japonica)
European Hornbeam (Non-columnar) (Carpinus betula)
Other trees as reviewed and approved by the community development director (Ord. 1904 § 1, 2003; Ord. 1815 § 1, 2000; Ord. 1629 § 1, 1996. Formerly 12.18.130).