Agenda - Council Work Session - 02/28/2017

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allows water to slowly infiltrate into and around the root ball. Treegator® bags can also be used to provide a slow delivery of water over the root balls of establishing trees and shrubs. Mulching trees and shrubs maximizes water uptake When trees and shrubs are planted into turf, competition for nutrients, water, and space occurs below ground between turf roots and woody plant roots. Turf wins because its dense fibrous root system prevents woody plants from producing water- and nutrient -absorbing roots in the top few inches of soil. As a result, woody plant establishment and growth is slower in turf areas than in mulched or bare soil areas. To optimize root production, water uptake, and establishment of newly planted trees and shrubs: 1. Eliminate turf and weeds from the base of the plant out to several feet beyond the plant canopy. 2. Leave the top of the root ball bare and start the mulch application at the outer edge of the root ball. 3. Apply a three inch layer of organic mulch around newly planted trees and shrubs in a circle that extends several feet beyond the tree or shrub canopy. Mulching around newly planted trees and shrubs with organic materials (wood chips, pine needles, etc.) has several advantages over bare soil cultivation. Mulch: • decreases water evaporation from soil. • serves as a sponge that prevents runoff around plants growing in heavy clay soils or on sloped sites. • helps to control seed germination and growth of weeds. • insulates soil and buffers extreme summer and winter soil temperatures. • reduces soil compaction from mowing equipment. • prevents damage to stems and trunks by lawn mowers and weed cutters. • improves soil health (increases microbial activity, nutrient- and water -holding capacity, soil pore spaces, and air penetration) as it decomposes. Deep mulch applications can be problematic because they may: • prevent movement of rain or irrigation water into the root ball of newly planted trees and shrubs. This can result in root desiccation and plant stress. • lead to root production and growth in the mulch. This often results in circling and stem - girdling roots. • reduce oxygen levels around roots and cause root suffocation. • keep poorly drained soils too wet, which favors root rot development. • keep bark excessively wet when piled around trunks and stems. This may lead to bark decay. • create habitat for rodents that chew bark and girdle trunks and stems. Other images: