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Deciduous Shrubs

Deciduous Shrubs

Shrub Deciduous shrubs are commonly used in landscape plantings because they provide interesting shapes and textures, colorful foliage, flowers and twigs, fruits for wildlife food and winter color, pleasant fragrances, screening and sound reduction, and a variety of other attributes. Unlike evergreens, deciduous shrubs loose their leaves in winter and therefore can create with a changing landscape throughout the year.

Deciduous shrubs are the backbone of most landscapes. They help visually anchor buildings and structures to the landscape, provide underplantings for trees, and create a backdrop for herbaceous flowers. Because they are available in a variety of heights and widths, it is possible to find a deciduous shrub to fill most any space in the landscape. To remain attractive, however, shrubs need regular maintenance and care.

Click on any of the following headings and link to chapters that explain selection and maintenance of deciduous shrubs:

Choosing and Planting Deciduous Shrubs

Maintenance of Deciduous Shrubs
Pruning
Watering
Mulching
Fertilizing
Winter Protection
Animal Damage

Choosing and Planting Deciduous Shrubs

Shrub When choosing shrub species for a landscape planting, it is important to first analyze the site so that the shrub chosen is appropriate for the light, soil, and moisture conditions. It is important to observe the surrounding landscape, take a soil test, document how much sun the area receives each day, and determine the hardiness zone. Every possible aspect affecting the shrub should be considered first, and then a shrub species appropriate for the conditions can be chosen. If a shrub is chosen that is not adapted to the site conditions, the shrub will forever be stressed and require higher maintenance.

For more information on evaluating the existing site, see Site Survey

For more on selecting trees based on site and plant characteristics:
Elements of Design

It is also very important to determine exactly how much space this shrub will have. Squeezing a 4-foot wide shrub in a 3-foot wide space will mean extensive pruning to keep that shrub within its space. If that regular pruning is not done, the landscape's appearance will be diminished because of crowding and the shrub not be able to reach its mature, attractive size.

Shrub Shrubs are available from nurseries and garden centers throughout the growing season, and can be planted at any time. Like trees, deciduous shrubs are available as bare root, balled and burlapped, or as container-grown stock. These types of stock are described under the tree section at Choosing and Planting Deciduous Trees

Shrub Choose shrubs that look healthy and pest-free. Avoid shrubs that have visible problems such as leaf spots or insects. Also avoid shrubs that are thin, with fewer leaves than normal, or whose soil or root ball has been allowed to dry out. Unless it is a shrub that dies back to the ground in winter or blooms on new wood each year, such as spirea or hardy shrub roses, choose shrubs with good branch structure.

Planting shrubs is similar to planting trees, except they usually do not require staking to prevent tipping unless they are very large specimens. For detailed instructions on planting bare root, balled and burlapped and containerized stock, see Planting Bare Root, Containerized and Balled and Burlapped Trees and Shrubs.

Additional information:
Trees & Shrubs for Clay Soil
Caring for New Plantings

Maintenance of Deciduous Shrubs

Most of our deciduous landscape shrubs are relatively care-free, and if planted in the right conditions, will require very minimal care. However, some maintenance will be helpful for shrubs to do their best, especially in times of adverse weather conditions.

Pruning
Shrubs may require periodic pruning for a variety of reasons. In a sustainable landscape, shrubs should be spaced so that there is enough room to reach their full, mature size without the need for size-reducing pruning. Still, pruning may be needed to:

  • Remove dead, dying or diseased branches
  • To increase flower and fruit production
  • To improve or maintain the desired form
  • To improve or maintain the shrub's bark color
  • To remove crossing or wayward branches
  • To encourage vigorous growth
Renewal Pruning: Older, overgrown shrubs may benefit from renewal pruning to reduce the overall size of the plant and to encourage young, flower-producing growth. Pruning entire branches back to the ground typically encourages growth at the base of the shrub. This can be useful to eliminate old wood and rejuvenate a shrub so that there is more flower-producing young growth. Thinning a shrub in this way maintains the plant's overall shape and is particularly useful with shrubs that sucker from the crown. Never remove more than 1/3 of the total number of branches (canes) in one season.

Pruning

Shrubs Thinning: With suckering shrubs that produce multiple stems from the crown, annual thinning can maintain young growth and good flower production. This will also maintain the plant's natural shape, but may keep the overall size of the shrub a bit smaller. Remove a few of the largest, oldest canes each year to prevent them getting old. This is especially useful to maintain colorful twig color on shrubs such as red-twigged dogwood, since older canes loose their color.

Heading Back: New growth on deciduous shrubs typically develops at the ends of branches. Thus, pruning away the terminal buds at the ends of branches causes lateral buds or side shoots to develop. This creates a bushier, fuller shrub. Heading back can be used to reduce the size of most types of shrubs. Branches should be cut back to within 1/4 inch of a larger branch or bud. Be sure to not leave a stub longer than 1/4 inch. "Pinching" involves removing just the shoot tip to cause more side branching. This technique is typically used on young shrubs to create a fuller plant as the shrub matures.

Shearing Shearing: Shearing is used to remove new shoots on shrubs being used in formal plantings or hedges. Few shrubs are conducive to shearing, and most are evergreens. When shearing for hedges, the tops must be narrower than the bottom so that light is able to reach the lower branches. Each time you shear a hedge, you should leave 1" of the previous growth so that the shrub can initiate new growth. Shearing typically eliminates or reduces the amount of flowers and overall foliage, and destroys the shrub's natural shape. Most shrubs should not be sheared, especially in an informal landscape design.

Deadheading: While deadheading does not affect the plant's overall growth, it involves removing faded flowers in an attempt to encourage more flowering and to improve the appearance of the shrub. It is typically done by hand as needed. Common deciduous shrubs that benefit from deadheading are spirea and shrub roses.

Deadheading When pruning, it is a good idea to disinfect pruning tools between shrubs to reduce the spread of disease. In order to kill most pathogens, tools should be dipped in a 10% bleach solution or alcohol.

Remember that pruning shrubs usually encourages new growth near the pruning cuts. Be sure to keep in mind the objective in pruning shrubs so that new growth will emerge as desired. Like deciduous trees, the use of wound dressings is not recommended as it can interfere with the plant's ability to heal. This is true even in the case of large cuts.

Most spring-flowering shrubs produce flower buds on one-year-old wood during the summer. The best time to prune these shrubs is immediately after they are done flowering each year, before they set flower buds for the next year. If these shrubs are pruned late in the summer or over winter, you will be pruning away flower buds.

Flower Summer-flowering shrubs typically produce flower buds on new growth in the spring. Pruning is recommended when these shrubs are dormant, such as in late winter before they begin to leaf out. Pruning when dormant may also reduce disease or insect infestations, which are also dormant during winter, and allow the plant's wounds to heal prior to the growing season.

Because pruning typically encourages new growth, it is not recommended to prune late in summer. New growth triggered by late-summer pruning may not harden off in time for cold winter weather, which can result in dieback or other damage.

For more information about pruning:
Pruning Trees and Shrubs
Hedges: Planting and Pruning

Additional information:
Caring for Deciduous Shrubs

Watering
When planted, shrubs should be watered thoroughly to wet the entire root zone and surrounding area. During the first year, the shrub should be watered when the soil begins to dry out. Like newly planted trees, an inch of water a week is required for newly-planted shrubs. Feel the soil near the shrub about 1-inch deep. If the soil feels dry, thoroughly soak the soil around the root zone. Avoid overwatering - it can be just as harmful as underwatering. Plant roots need oxygen as well as water. Too much water fills the air pockets between soil particles and creates an anaerobic environment. This can result in root rot and an environment favorable to other pathogens such as fungi and bacteria.

Once established, most deciduous shrubs only need supplemental watering during periods of drought. A good soaking once every week or 10 days during dry periods will be sufficient.

Mulching
Applying organic mulch around the base of shrubs can help retain moisture, control weeds, moderate soil temperature, and give a nice appearance to the landscape. Most any organic material can be used as mulch, including shredded wood or bark, wood chips, pine needles, cocoa bean hulls, straw, ground corncobs, or any other available organic matter.

To be effective, mulches should be applied so that when settled, it is 3-4 inches deep. However, be sure to pull mulch away from the trunk or stem of the plant. Mulch left against the bark can cause moisture buildup which can rot the bark and cause severe injury to the plant. Do not use a landscape fabric or plastic when using organic mulches.

Inorganic materials often used as mulch, such as landscape rocks, can also be used. However, rock tends to absorb heat during the day and release it at night, which can be stressful for plants. Also, you will need to use a landscape plastic or fabric under the rock to control weeds, which you would not use with organic mulch. If the shrubs are mulched with an organic material such as wood chips or shredded wood, additional applications of nitrogen fertilizer may be needed. As the mulch decomposes, microorganisms compete for nitrogen which may result in nitrogen deficiencies in the plants.

Additional information:
Mulching the Home Landscape

Fertilizing
Deciduous shrubs can benefit from periodic fertilization. Fertilizer should be applied in late fall or early spring. Fertilizing late in summer can cause a flush of tender growth that will not be hardened off before winter and will be damaged. Many flowering shrubs also produce flower buds in mid- to late summer; applying fertilizer at that time may cause more vegetative growth and less flower buds.

Shrub The only way to know what type of fertilizer to apply is to take a soil test. In many cases, soils have enough phosphorous and potassium, so only nitrogen fertilizer is needed. For information about the basics of fertilizers, see Fertilizer Basics for Trees and Shrubs.

Follow package instructions for amounts of fertilizer to apply. A rule of thumb is to apply 4 oz. per foot of the shrub's height or spread. To a certain degree, the more fertilizer you add the more growth you can expect. You may therefore wish to apply slightly more fertilizer to young plants and less to plants that have already neared their desired size.

Additional information:
Preventing Pollution Problems from Lawn and Garden Fertilizers

Winter Protection
Winter Some deciduous shrubs can benefit from extra care for winter months. While most deciduous shrubs are not susceptible to sun scald like deciduous trees are, those with larger central stems or trunks exposed to full sun may benefit from wrapping. Newly planted shrubs may also benefit from extra mulch over the root zone to prevent damage from the freeze/thaw cycles of late winter, which can damage roots.

Salt used to melt ice on pavement can damage shrubs in two ways. Shrubs planted near roadways often suffer from salt spray damage, resulting in bud death and twig dieback. New growth then occurs mainly near the branch bases, creating clusters of twigs called "witches' brooms."

Salt can also get into soil in several ways, including being sprayed by traffic, plowed off the road, or by draining with melted snow and ice onto soil surfaces. Salt in the soil can kill roots directly or can prevent them from taking up water, causing drought injury. Often, injury cased by salt exposure does not show up for a year or more. Symptoms including a blue-green cast to the foliage, small leaf size, marginal leaf burn, early fall color and leaf drop, and stunted growth.

Try to plant shrubs where they will not be exposed to excessive winter deicing salt, and use as little salt near landscape plantings as possible. If salt will be present, choose shrub species that are tolerant of higher soil salt levels.

The buildup of ice or heavy wet snow may cause damage to shrubs during winter; however, in most cases, freezing rain buildup on shrubs will not harm them. Branches may sag, but are flexible enough to withstand the weight and will bounce back once the ice melts or falls off. If ice buildup is less than 1/8 inch thick, it is best to leave it alone and not risk damaging branches while trying to remove the ice.

In cases of extreme ice buildup where there is a risk of branches breaking because of the weight, it is helpful to carefully remove some of the ice. Use a rake handle or other round stick to gently tap the branches to remove some of the ice. It is not necessary to remove all of the ice, just enough to eliminate the threat of breakage because of the weight of the ice.

Always beware of power lines and other hazards resulting from the ice storm that may be present.

For more information:
Protecting Trees and Shrubs Against Winter Damage
Ice, Snow and Wind Damage
Minimizing De-Icing Salt Injury to Trees
Tree Wraps and Guards
Winter Injury on Trees

Animal Damage
Shrubs face a significant threat of injury due to rodents and other animals feeding on the bark and twigs. This feeding may permanently disfigure the shrub, and if damage is severe enough, the shrub will die. Thin barked or young trees are most susceptible to damage by animals, and certain species, such as dwarf winged Euonymous, are typically subject to considerable damage by rabbits.

Bunny Protect the shrub from rabbits and mice by placing a ring of 1/4 mesh hardware cloth around the trunk of taller shrubs, and around the entire plant if the shrub is smaller. The mesh should be buried 1-2 inches below the soil line to protect against burrowing rodents, and should extend two feet above the expected snow level to protect against rabbits. There are also commercial repellents available to control animal damage. Spray repellents on the plant, hang them in the branches or place them on the ground around the shrubs. However, repellents often don't last very long and typically require re-application periodically, especially after rain or heavy snow.

Deer can cause severe damage to shrubs from feeding on tender buds and twigs. Protection with fencing is sometimes possible, but difficult. In addition to sprays, hanging repellents from branches can also be effective. Common repellents include small bags of human hair, blood meal, or bars of soap. A variety of commercial repellants are also available.

For more information about the selection, planting and care of trees and shrubs, see:

Plant Injury Due to Turfgrass Broadleaf Weed Herbicides
Living Snow Fences
Energy Saving Landscapes

See also: Trees and Shrubs: Diseases, Insects and Other Problems

 
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