Sunday, September 4, 2016

Successful Planting of Trees and Shrubs

Fall is the best time for planting woody ornamentals and trees.
Two of the most common causes of tree and shrub problems are improper planting techniques, and failure to select the right plant for the site. These problems are easily avoided through a bit of research and preparation. This document will show you how to get the results you expect. 
1. Plant in the Fall - The survival rate of trees and shrubs planted in the fall is much greater than those planted other times of the year. Cooler temperatures slow evaporation of soil moisture. This promotes root growth, which will help the plant survive our hot summers .

2. Evaluate the Site - Before you plant, consider the following:
  • Soil Fertility - Collect a soil sample and correct nutrient deficiencies before planting.
  • Soil Structure and Texture - The red clay soils of Durham County are well suited to growing healthy plants. However, they are very susceptible to compaction. Deep tillage will alleviate this compaction. If you have the gray mucky clay of the Triassic Basin, you may need to construct raised beds using high quality topsoil (as opposed to "fill dirt").
  • Exposure - How much sun does the site receive?
  • Drainage - Does the soil stay wet for prolonged periods?
  • Available Space - What size plant would be appropriate for the space? How close are nearby buildings, trees, flowerbeds, etc.? Are there constraints on how far the roots can grow (e.g. a curb, driveway, sidewalk, etc.)? The roots of a large tree may extend fifty feet or more from the trunk. Are there overhead power lines or building overhangs?

3. Determine the Function the Plant Will Serve - What role will the plant play in your landscape? Are you looking for a specimen plant to be a focal point? Are you trying to develop a privacy hedge of a certain height? Are you trying to soften the edges of a building, e.g. with a tall, columnar evergreen? Do you need to add more winter interest to your landscape with berries, interesting shapes or attractive bark?
4. Choose the Appropriate Species or Variety - Once you have determined the site condition and plant function choose a species or variety that will thrive in those conditions AND serve the desired function. There are many good reference books that will help you make a decision, or you can call the Master Gardeners5m for suggestions. Local gardens, arboreta, nurseries, and landscapers are another source of ideas. Factors to consider include hardiness rating, preferred soil conditions, susceptibility to pest problems, growth rate, shape/form, height and spread at maturity, color, texture, etc.
5. Buy Quality Plant Material - Consider the following in your pre-purchase inspection:
  • Form - Does the plant have an attractive shape? Know the preferred structure for the species you have chosen (e.g. central leader, multi-stem, etc.) and select a plant that conforms.
  • Health - Does the plant appear to be growing vigorously? Are there any signs of insects or disease?
  • Trunk/Branches - Is there any damage to the trunk or branches? Is the bark intact? If it was pruned in the nursery, were the pruning cuts made correctly?
  • Roots - Does the plant have a full, vigorous root system?

6. Handle the Plant Carefully - Lift the plant by the container or root ball, NEVER by the trunk. Protect the canopy from getting wind blown during transport.
7. Prepare the Planting Hole - It's better to put a ten-cent plant in a ten-dollar hole than to put a ten-dollar plant in a ten-cent hole. If your soil test report indicates a need for lime or phosphorous, apply the recommended amount before planting and incorporate it into the soil. In most cases, it is best NOT to amend the planting hole with organic material. The planting hole should be no deeper than the root ball, and two to three times as wide. The root ball should be set on firm, undisturbed soil. If drainage is a concern, it may be planted so that one-third to one-half of the root ball is above grade.
8. Install the Plant
  • Container plants - Carefully remove the plant from the container. If you notice circling roots, tease them out so that they will grow straight (or cut them if necessary). If you can do so without severely damaging the root system, shake off some of the potting medium. Install the plant so that the crown or trunk flare (point where the root system meets the trunk) is even with grade and not covered by soil.
  • Balled and burlapped plants - Place the balled and burlapped plant into the planting hole. Being careful not to damage the root system, remove as much burlap, string, and wire as possible. At a minimum, fold back the burlap to expose at least the top third of the root ball. It may also be beneficial to carefully loosen

9. Mulch the Planting Area -Cover the planting area with NO MORE THAN 3 inches of mulch. Be sure the mulch is pulled away from the trunk.
10. Water the Plant - Soak the soil in the planting site. For large plants, it may be helpful to fill in half of the soil, irrigate, fill in the remaining soil, and irrigate again.
11. Develop a Maintenance Plan - Regular inspections to avoid moisture stress are critical. The frequency of such checks will depend upon temperature and rainfall. During the first 3 months, check the soil moisture level twice a week (depending on temperature and rainfall). After 3 months, check soil moisture weekly. After 6 months, check every two weeks. If stakes and guy lines are used, they should be checked monthly for signs two weeks. If stakes and guy lines are used, they should be checked monthly for signs of girdling. They should be removed after 6 months. Decide who will be responsible for the maintenance activities, and clearly communicate your expectations.
Miscellaneous Considerations:
Staking -Staking and guying are normally unnecessary, but can reduce the risk of wind damage. When planting large numbers of trees, trees with high value, or tall trees with full canopies, staking may be advisable. If stakes and guy lines are used, there should be enough play in the guy lines so that the tree an move slightly in the wind. The guy lines should be attached to the tree in such a way that they do not constrict or damage the trunk or branches. Stakes and guy lines should be removed after about 6 months.  
Pruning - In most cases, pruning of newly installed trees and shrubs is not recommended, except to correct structural defects (e.g. damaged limbs, crossed branches). Moisture stress should be avoided by supplying adequate water.
Soil Berms - If the tree or shrub is planted in a remote site that is difficult to irrigate, you may want to construct a berm of raised soil around the trunk. This berm will slow the runoff of rainwater, allowing for better water infiltration. The berm should be constructed at least 12 inches away from the trunk. A height and width of 3 to 4 inches is sufficient.

Urban Horticulture Note No. 7
Prepared by: Durham County Master Gardener' Program
721 Foster St. Durham, NC 27701
Revised October 26, 2007 

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