Montgomery County Maryland Forestry Board

Montgomery County Forest Conservancy
District Board

Section 1: Proper Mulching Techniques
Section 2: Staking and Guying Landscape Trees

Section 1: Proper Mulching Techniques

Mulches are materials placed over the soil surface to maintain moisture and improve soil conditions. Mulching is one of the most beneficial things a home owner can do for the health of a tree. Mulch can reduce water loss from the soil, minimize weed competition, and improve soil structure. Properly applied, mulch can give landscapes a handsome, well-groomed appearance. Mulch must be applied properly; if it is too deep or if the wrong material is used, it can actually cause significant harm to trees and other landscape plants.

Benefits of Proper Mulching

• Helps maintain soil moisture. Evaporation is reduced, and the need for watering can be minimized.
• Helps control weeds. A 2-4 inch layer of mulch will reduce the germination and growth of weeds.
• Mulch serves as nature’s insulating blanket. Mulch keeps soils warmer in the winter and cooler in the summer.
• Many types of mulch can improve soil aeration, structure (aggregation of soil particles), and drainage over time.
• Some mulches can improve soil fertility.
• A layer of mulch can inhibit certain plant diseases.
• Mulching around trees helps facilitate maintenance, and can reduce the likelihood of damage from "weed whackers" or the dreaded "lawnmower blight."
• Mulch can give planting beds a uniform well-cared-for look.

Trees growing in a natural forest environment have their roots anchored in a rich, well-aerated soil full of essential nutrients. The soil is blanketed by leaves and organic materials that replenish nutrients and provide an optimal environment for root growth and mineral uptake. Urban landscapes, however, are typically a much harsher environment with poor soils, little organic matter, and big fluctuations in temperature and moisture. Applying a 2-4 inch layer of organic mulch can mimic a more natural environment and improve plant health.

The root system of a tree is not a mirror image of the top. The roots of most trees can extend out a significant distance from the tree trunk. Although the guideline for many maintenance practices is the drip line the outermost extension of the canopy the roots can grow many times that distance. In addition, most of the fine absorbing roots are located within inches of the soil surface. These roots, which are essential for taking up water and minerals, require oxygen to survive. A thin layer of mulch, applied as broadly as practical, can improve the soil structure, oxygen levels, temperature, and moisture availability where these roots grow.

Types of Mulch

Mulches are available commercially in many forms. The two major types of mulch are inorganic and organic. Inorganic mulches include various types of stone, lava rock, pulverized rubber, geotextile fabrics, and other materials. Inorganic mulches do not decompose and do not need to be replenished often. On the other hand, they do not improve soil structure, add organic materials, or provide nutrients. For these reasons, most horticulturists and arborists prefer organic mulches.

Organic mulches include wood chips, pine needles, hardwood and softwood bark, cocoa hulls, leaves, compost mixes, and a variety of other products usually derived from plants. Organic mulches decompose in the landscape at different rates depending on the material. Those that decompose faster must be replenished more often. Because the decomposition process improves soil quality and fertility, many arborists and other landscape professionals consider this a positive characteristic, despite the added maintenance.

Not Too Much!
As beneficial as mulch is, too much can be harmful. The generally recommended mulching depth is 2 to 4 inches. Unfortunately, North American landscapes are falling victim to a plague of over mulching. A new term, "mulch volcanoes," has emerged to describe mulch that has been piled up around the base of trees. Most organic mulches ust be replenished, but the rate of decomposition varies. Some mulches, such as cypress mulch, remain intact for many years. Top dressing with new mulch annually (often for the sake of refreshing the color) creates a buildup to depths that can be unhealthy. Deep mulch can be effective in suppressing weeds and reducing maintenance, but it often causes additional problems.

Problems Associated with Improper Mulching

• Deep mulch can lead to excess moisture in the root zone, which can stress the plant and cause root rot.
• Piling mulch against the trunk or stems of plants can stress stem tissues and may lead to insect and disease problems.
• Some mulches, especially those containing cut grass, can affect soil pH. Continued use of certain mulches over long periods can lead to micronutrient deficiencies or toxicities.
• Mulch piled high against the trunks of young trees may create habitats for rodents that chew the bark and can girdle the trees.
• Thick blankets of fine mulch can become matted, and may prevent the penetration of water and air. In addition, a thick layer of fine mulch can become like potting soil and may support weed growth.
• Anaerobic "sour" mulch may give off pungent odors, and the alcohols and organic acids that build up may be toxic to young plants.

Proper Mulching
It is clear that the choice of mulch and the method of application can be important to the health of landscape plants. The following are some guidelines to use when applying mulch.

• Inspect plants and soil in the area to be mulched. Determine whether drainage is adequate. Determine whether there are plants that may be affected by the choice of mulch. Most commonly available mulches work well in most landscapes. Some plants may benefit from the use of slightly acidifying mulch such as pine bark.
• If mulch is already present, check the depth. Do not add mulch if there is a sufficient layer in place. Rake the old mulch to break up any matted layers and to refresh the appearance. Some landscape maintenance companies spray mulch with a water soluble vegetable-based dye to improve the appearance.
• If mulch is piled against the stems or tree trunks, pull it back several inches so that the base of the trunk and the root crown is exposed.
• Organic mulches are usually preferred to inorganic materials due to their soil-enhancing properties. If organic mulch is used, it should be well aerated, and preferably, composted. Avoid sour-smelling mulch.
• Composted wood chips can make good mulch, especially when they contain a blend of leaves, bark, and wood. Fresh wood chips may also be used around established trees and shrubs.
• For well-drained sites, apply a 2-4 inch layer. If there are drainage problems, a thinner layer should be used. Avoid placing mulch against the tree trunks. Place mulch out to the tree’s drip line or beyond.

Remember: if the tree had a say in the matter, its entire root system (which usually extends well beyond the drip line) would be mulched.

Section 2: Staking and Guying Landscape Trees

Kansas Forest Service, Kansas State University

STAKING AND GUYING LANDSCAPE TREES

Staking or guying landscape trees on exposed sites can be an important ingredient of successful tree planting in the Great Plains. While current research seems to suggest that such practices may be more harmful than good, or are unnecessary, such is not the case on exposed, windy sites typical of much of Kansas.

The root ball of a newly planted but unstaked tree will tend to roll or pivot in the ground, resulting in tree lean or blow-over. In addition, trunk movement from strong wind, at or below the soil line, will break the root ball, destroying roots and resulting in a wobbly tree. Such a plant will usually die because constant movement will prevent root establishment. These problems can be avoided by proper staking or guying of a newly planted tree.

Most deciduous trees 5 to 6 feet or larger are candidates for staking when planted on an exposed site. The larger the tree, the more important it is to provide extra support. Usually, a deciduous tree up to 1.5 to 1.75 inches in caliper (10 to 12 feet in height) can be staked using the method illustrated in Figure 1. A tree larger than this will need to be supported by a three-way guying system (Figure 3).

An upright evergreen 4 to 5 feet or larger should be staked or guyed on exposed sites. A tree less than 6 feet in height can be supported by staking, but you may find it easier to install the guying method because of low limbs and plant density. Evergreens more than 6 feet in height require guying.

Staking and guying of a tree must be done properly, and the system must be maintained. It is best to avoid using wire and cable around the trunk, but if support must be provided in this manner, be sure to protect the tree by running the wire through a length of rubber or vinyl hose to serve as padding. Commercial rubber, nylon, or vinyl ties are less likely to damage the tree and should be used whenever possible. The wooden stake should not rub against

the trunk. A properly installed tie will separate the tree trunk from the stake,

providing a cushion. Other staking systems or newer staking technologies may Fig. 1. When staking, support the tree 18 to 24

be appropriate for use in certain circumstances. Contact your district or inches above the ground.

community forester for additional information.

Support the tree low on the trunk. The purpose of staking or guying is to prevent movement of the lower trunk and root system. Movement of the top is desirable and will strengthen the tree.

Check a staked or guyed tree monthly during the growing season and after storms or strong wind. The system should be snug, but not to the point of making an impression on the stem or trunk. If that happens, loosen the tie or wire around the trunk. Do not stake or guy a tree any longer than necessary. Stakes should be removed after one growing season, but may remain in place for a second season only if additional support is required.

Staking Specifications:

When working with a nursery, make sure to specify size and location of trees to be staked.

On exposed sites, stake deciduous and upright evergreen trees immediately after planting with a 2 x 2-inch x 5-foot stake as follows: (1) position the stake

along the west side of the tree so the prevailing winds will move the tree Fig. 2. When staking a tree, place the stake so

away from the stake (Figure 2.); (2) drive the stake (pointed on the downward the prevailing winds move the tree

end) 12 to 18 inches into undisturbed soil outside the planting pit at a 45-degree away from the stake.

angle, crossing and supporting the trunk 18 to 24 inches above the soil surface

(Figure 1); (3) secure the trunk to the stake using commercial ties or a wire tie

protected by a rubber/vinyl length of hose or pad in a loose figure eight shape

so the bark will not be injured and the trunk will not rest against the stake.

Guying Specifications:

Specify the size and location of trees to be guyed when working with a nursery.

On exposed sites, deciduous and upright evergreen trees should be guyed immediately after planting with a three-way system (Figure 3). Drive three 2 x 2 x 18-inch support stakes 10 to 12 inches into the ground at approximately 120 degrees from each other, outside the planting pit. Position stakes so that guy wires will be located at 45- to 60-degree angles from the ground. Guy wires should be No. 9 wire or larger and attached to commercial ties or pass through a rubber or vinyl length of hose so the wire does not come into contact with tree bark. Generally, wire Fig. 3. The three-way guying system should

support should be located near the lowest main branches on the tree. be used on larger deciduous and upright

evergreen trees.

This publication is made available in cooperation with the USDA Forest Service. .

Brand names appearing in this publication are for product identification purposes only. No endorsement is intended, nor is criticism implied of similar products not mentioned.

Publications from Kansas State University are available on the World Wide Web at: www.oznet.ksu.edu

Contents of this publication may be freely reproduced for educational purposes. All other rights reserved. In each case, credit Kim Bomberger, Staking and Guying Landscape Trees, Kansas State University, September 2005.