Landscape plans, as described above, shall be prepared by a licensed landscape architect, registered in the State of Illinois, and evaluated and approved based on the following design criteria:
(A) Scale and nature of landscape material. The scale and nature of landscape materials shall be appropriate to the size of the site and related structures.
(B) Selection of plant material. Plant material shall be selected for its form, texture, color, pattern of growth and suitability to local conditions.
(C) Shade trees. All deciduous shade trees shall have a minimum trunk size of two inches in caliper at planting, unless otherwise specified.
(D) Evergreen trees. Evergreens trees shall have a minimum height of six feet at planting and shall be incorporated into the landscape treatment of a site, particularly in those areas where year-round screening and buffering is required.
(E) Ornamental trees. Single stem ornamental trees shall have a minimum trunk size of three inches in caliper at planting, unless otherwise specified. Multiple stem ornamental trees shall have a minimum height of eight feet at planting, unless otherwise specified.
(F) Shrubs.
(1) Unless otherwise specified, all large deciduous and evergreen shrubs shall have minimum height of three feet at installation, and all small deciduous and evergreen shrubs shall have a minimum height of 18 inches at installation.
(2) Large shrubs shall be considered to be those shrubs that reach five or more feet in height at maturity. Small shrubs shall be considered to be those shrubs that can grow up to five feet in height if left unmaintained, but are generally kept at heights of 18 to 30 inches.
(G) Softening of walls and fences. Plant material shall be placed intermittently against long expanses of building walls, fences and other barriers to create a softening effect and to help break up long expanses of blank walls with little architectural detail.
(H) Planting beds. Planting beds may be mulched with shredded hardwood, granite mulch, river rock, feather rocks or similar materials. Lava rock is not permitted.
(I) Irrigation. Landscape design pursuant to the requirements of this subchapter shall recognize the need for irrigation and water conservation. Sprinkler irrigation systems may be required for certain landscaped areas, as determined by a landscape architect. The need for sprinkler irrigation systems shall be determined by the type of plant material and the condition/growing medium that they are installed in. For instance, whether there is a permanent means available to water plant material, such as hose bibs, shall be a consideration. All irrigation systems shall be designed to minimize the use of water.
(J) Energy conservation. Plant material placement should be designed to reduce the energy consumption needs of the development. In addition, landscaping designs shall take into account and make an effort to implement LEED policy and design standards, where appropriate.
(1) Deciduous trees should be placed on the south and west sides of buildings to provide shade from the summer sun.
(2) Evergreens and other plant materials should be concentrated on the north and west sides of buildings to dissipate the effect of winter winds.
(K) Species diversity. Diversity among required plant material is required not only for visual interest, but to reduce the risk of losing a large population of plants due to disease. Table 13: Diversity Requirements indicates the percentage of diversity required based on the total quantity of species being used. For instance, if a development requires 45 shade trees, no more than 18 trees nor less than five trees can be of one species, and there must be a minimum of five different species within the 45 trees.
TABLE 14-1: DIVERSITY REQUIREMENTS
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Total Number of Plants per Plant Type | Maximum of Any Species | Minimum of Any Species | Minimum Number of Species |
TABLE 14-1: DIVERSITY REQUIREMENTS
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Total Number of Plants per Plant Type | Maximum of Any Species | Minimum of Any Species | Minimum Number of Species |
1 - 4 | 100% | Not applicable | 1 |
5 - 10 | 60% | 40% | 2 |
11 - 15 | 45% | 20% | 3 |
16 - 75 | 40% | 10% | 5 |
76 - 500 | 25% | 5% | 8 |
501 - 1,000 | 30% | 5% | 10 |
1,000 + | 15% | 4% | 15 |
(L) Berming. Earthen berms and existing topographic features shall be incorporated into the landscape treatment of a site where there is sufficient space and, in particular, when berms and existing topographic features can be combined with plant material to facilitate effective screening. Minimum unretained berm side slopes shall be maintained at no less than a 4:1 slope ratio to prevent erosion and be properly and safely maintained. Retained slopes may be implemented with the appropriate terracing necessary to reduce the need for safety railing.
(Ord. 929, passed 1-25-11; Ord. 1076, passed 1-23-18) Penalty, see § 153.999