Winter Garden Preparation - Pruning

Now is the time to think about pruning the shrubs and trees in your garden.  Pruning in late winter, just before spring growth starts, leaves fresh wounds exposed for only a short length of time before new growth begins the wound sealing process. Another advantage of dormant pruning is that it’s easier to make pruning decisions without leaves obscuring plant branch structure.  

 Some of the reasons we prune plants are:

• To improve the appearance or health of a plant.
• To control the size of a plant. 
• To prevent personal injury or property damage.
• To train young plants.
• To influence fruiting and flowering. Proper pruning of flower buds encourages early vegetative growth.
• To rejuvenate old trees and shrubs. As trees and shrubs mature, their forms may become unattractive.

Types of pruning

Five basis techniques are used for pruning: pinching, heading back, thinning, renewal pruning, and shearing. Some plants require more of one method than another, but good pruning is usually a combination of several methods.

Pinching - is the removal of the terminal portion of a succulent, green shoot before it becomes woody and firm.

Heading back - involves removing the terminal portion of a woody branch by cutting it back to a healthy bud or branch. Heading back will stimulate shoot growth below the cut thus making the plant more dense.

Thinning - is the least conspicuous method of pruning and results in a more open plant without stimulating excessive new growth.  Thinning cuts a branch is cut off at its point of origin from the parent stem, to a lateral side branch, to the “Y” of a branch junction, or at ground level.  Plants pruned by thinning include crapemyrtle, magnolia, viburnums, spireas, smoketree, and lilac.

Renewal pruning (rejuvenation) - involves removing the oldest branches of a shrub by pruning them near the ground, leaving only the younger, more vigorous branches which may also be cut back. Plants pruned by renewal include abelia, deutzia, forsythia, mockorange, spirea, and weigela.



 
Types of Tools

Shearing - involves cutting the terminal of most shoots with shearing or hedge clippers. This method should not be used on foundation plants but should be restricted to creating formal hedges.

Use hand pruners to cut stems up to 3/4 inches in diameter. Two types of pruners are available: bypass and anvil. Bypass pruners have sharpened, curved, scissors-type blades that overlap. Anvil pruners have straight upper blades that cut against flat lower plates. Although anvil pruners are usually cheaper, they tend to crush stems as they cut. Furthermore, the width of the anvil can prevent you from reaching in to get a close cut on narrow-angled stems. Due to these drawbacks, bypass pruners are generally recommended. 

Use lopping shears to cut through branches that are up to 1 3/4 inches in diameter. Loppers have long handles to give you extra reach and better cutting leverage. For heavy duty pruning jobs, select loppers with ratchet joints or those with gears. Look for loppers with shock-absorbing bumpers between the blades, to lessen arm fatigue. Again, bypass blades are preferable.

Use pruning saws to remove stems you cannot cut with hand pruners or lopping shears. Pruning saws come in many sizes, with either straight or curved blades, and teeth that are either fine or coarse. Use a finely-toothed, curved pruning saw to remove branches up to 2 1/2 inches in diameter. You can make a clean cut with this type of saw where access is difficult. Use a coarsely toothed saw for heavy branches 3 inches or more in diameter.

Use pole pruners to cut out-of-reach branches up to 2 inches in diameter. Pole pruners consist of blades attached to stationary hooks which are mounted on long wooden or aluminum poles. A cord or chain is used to control the cutting action of the spring-loaded blade.  Pole pruners are especially valuable on jobs where ladders would be inconvenient or would damage the tree. 

Use chain saws to remove branches greater than 3 inches in diameter. Many types and sizes of chain saws are readily available, powered by gasoline or electricity. In selecting a chain saw, carefully consider the tasks for which it will be used. Chain saws should be used only with appropriate safety gear by people who fully understand their operation. 

Use hedge clippers or pruning shears to trim thin-stemmed hedges. Manual hedge clippers, and ones powered by gasoline or electricity, are available. All types shear off growth in a straight line, regardless of branch collar or bark ridge location. If you have a long hedge, you may have to use hedge clippers when hand pruning is impractical. 

Select quality tools. They will last longer and make pruning more pleasurable. For maximum effectiveness, sharpen blades regularly and dry and oil them after each use. Use a file or whetstone for sharpening hand tools and have an experienced professional sharpen chain saws and power hedge clippers.



Pruning at the proper time can avoid certain disease and physiological problems:

• To avoid oak wilt disease DO NOT prune oaks during April, May, or June. If oaks are wounded or must be pruned during these months, apply wound dressing to mask the odor of freshly cut wood so the beetles that spread oak wilt will not be attracted to the trees.
• To avoid increased likelihood of stem cankers, prune honey locusts when they are still dormant in late winter. If they must be pruned in summer, avoid rainy or humid weather conditions.
• Prune apple trees, including flowering crabapples, mountain ash, hawthorns and shrub cotoneasters in late winter (February-early April). Spring or summer pruning increases chances for infection and spread of the bacterial disease fireblight. Autumn or early winter pruning is more likely to result in drying and die-back at pruning sites.
• Some trees have free-flowing sap that “bleeds” after late winter or early spring pruning. Though this bleeding causes little harm, it may still be a source of concern. To prevent bleeding, you could prune the following trees after their leaves are fully expanded in late spring or early summer. Never remove more than 1/4 of the live foliage. Examples include:
  
  • all maples, including box elder
  • butternut and walnut
  • birch and its relatives, ironwood and blue beech
   

Pruning wounds plants, but plants respond differently to wounding than do animals. In plants, damaged areas are covered by callus tissue to close wounds.  Plants also wall off, or compartmentalize, wounds, which limits any decay that results from wounding, or from the natural death of branches. Pruning during the winter and using pruning techniques that minimize plant wounding will help you to maintain a beautiful and healthy landscape.


Additional Resources

University of Minnesota - Pruning Trees and Shrubs

NC State University - Winter Pruning

Michigan State University - Winter Pruning Advatages

Oregan State University - Winter Pruning Temperatures

Rutgers University - Plant and Pest Advisory March 15, 2007

NC State - Pruning Shrubs

Winter Garden Preparation - Soil

Ideal garden soil should be loose, deep and crumbly. It should drain well, water should not stand on top after rain and contain plenty of organic matter. Good garden soil will deliver the right mixture of air, water, and nutrients to grow a large root system and strong, productive plants. Vegetables and other plants will grow satisfactorily with a wide range of soil types from sand to clay if certain steps are followed for overcoming their basic short-comings.

Begin preparing the soil by removing all plant material from this year's garden. Dead roots, stems and foliage can harbor insects and diseases that emerge in the spring to infect next year's garden.

Soil testing can provide important information to make decisions concerning:

• How much lime to use in lawns, vegetable or flower beds.
• How much fertilizer to use on lawns, vegetables, flowers, and shrubs.
• How to adjust the soil pH for optimum growth of acid-loving plants such as azaleas and rhododendrons.
• How to apply soil amendments and fertilizer to improve soil quality.
• Nutrients that are lacking or in excess in the soil.
• Amount of lead or other metals in the soil.

Clay soils have the ability to hold moisture well and usually contain more nutrients than light soils. They dry slowly in the spring so early planting of crops is not possible. Water penetration is slow so irrigation water often runs off instead of entering the root zone. 

Sandy soils are easy to work but have low water holding capacities, so plants may suffer from moisture stress in hot weather. Nutrients may be lost as irrigation water moves downward through the soil. 

These almost opposite drawbacks of both soil types can be corrected by the same technique-adding organic matter. Fine clay particles can be physically separated by coarse organic material. Nutrient and water holding qualities of sandy soils can be increased. As the organic matter breaks down, its components continue to have soil improving characteristics. 

Begin by incorporating 2 to 3 inches of organic matter 6 to 8 inches deep. This application will not last forever and you should plan to add about 2 more inches each year. With heavy soils, you’ll need 2 or 3 years to see much of an improvement. Summer mulching or compost addition will be helpful.
 
When the soil has dried and warmed sufficiently, spade or rototill to a depth of about 6–8 inches. Garden soil doesn’t need to be “flour-fine.” Leave marble-sized particles and crusting will not be as severe as with over prepared soil. You’ll need to use a rake to pulverize clods. Level and compact the soil for a firm seedbed. The final soil surface should be as level as possible for uniform water penetration. 

Additional Resources

Rutgers Univeristy - How to Have your Soil Tested 

University of Minnesota - Organic Matter Management

Utah State University - Preparing Garden Soil

University of Maryland - Prepare Your Soil 

Alabama A&M and Auburn Universities - Raised Bed Gardening