11-25-2002 Council Packet - Laserfiche WebLink

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'trr drainage conditions to ensure that the landscaping is properly irrigated. This system needs to include rain sensors and provisions for ongoing monitoring and mainteiuince. 25. The plant palettes identifled on tlie landscape master plan and related landscape area plans include a mix of non-native and native deciduous, coniferous and ornamental trees, shrubs, perennials, grasses and gioundcovers. The tree and shrub palette includes a good variety of plants. The proposed plants are generally dependable and suitable for their proposed uses and locations and will provide seasonal variation and interest. Three of the trees (Redbud, Autumn Purple Ash and Grecii Mountain Sugar Maple) are of borderline hardiness in this locale The plan colls for 2,38, and 39 of these trees re.spectively. These trees should on;. ’ be planted from stock grown locally or in the same hardiness zone. Depending on the ex|>osure and other conditions at the individ>ial planting locations, these trees may experience wintti injury and dieback during some >'ears. The project Landscape Architect may need to substitute hardier trees in critical or exposed locations. The Red Sunset and Green Mountain Sugar Maples arc generally sensitive to deicing salts. They arc proposed for use within the boulevards of Kelly Parkway and the private streets. However, the roads ser\ ing the project will have low speed limits, which should reduce salt spray and minimize the problem. Wliere possible, the boulevards should be graded to direct salt contaminated runoff away from the Uce pits and planting areas. Most of the plants called for on the plans require good drainage and will not tolerate extended peiiods of flooding or prolonged saturated soil conditions. Drainage problems, in combination, with over watering are the most frequent causes of significant plant loss in development projects with similar soil conditions. It’s critical to identify and address site and soil drainage problems prior planting, llie actual soil structure, compaction and drainage conditions in the project’*, landscaped aicas should be monitored during construction and evaluated prior to planting to ensure compatibility with the selected plants. Areas with heavy or compacted soils and poor surface or subsurface drainage should be noted and the conditions or planiinj^ addressed by the project Landscape Architect and Landscape Contractor prior to planting. As this project may involve significant amounts of impoitcd ii.t, the soils that will be placed within the root growih zones should be sampled and tested to identify soil characteristics and pi I. and to validate the use of pi I s nsitive plants. Northern Red Oak is subject to chloaisis when planted in higtily alkaline soils. Niobe Weeping Willow is proposed along the Willow Road trail imd in other wet locations. Niobe W’illow can be a dramatic and attractive tree and it is generally suitable in those locations. However, it is a very fast growing, short lived (typically 30 to 50 years) and weak wooded tree that is frequently damaged and deformed by ice and wind storms. Depending on the stiil conditions and flooding duration, alternatives could be used that will generally live longer and require less maintenance (i.e. Swamp WTiite Oak. Red Maple). I60l/if02^27S9/2S40 Dahlstront Larh^^'orm Dcwlopmetu **StoneB<r'Page