Planting and transplanting trees and shrubs : Yard and …

Extension > Garden > Yard and Garden > Planting and transplanting trees and shrubs

Jeffrey H. Gillman, Nursery Management Specialist, Department of Horticultural Science Gary R. Johnson, Urban Forester, Department of Forest Resources

Trees and Shrubs should be selected for a site based on the ability of the plant to tolerate the soil, light, climate, and residential conditions present at that location. Information on the ability of various shrubs to tolerate environmental conditions in Minnesota can be found in the following guides published by University of Minnesota Extension:

The conditions of the planting site are as important as the plant. Soil type and drainage, available water and sunlight, exposure to drying winds, and other factors must be considered. Attempting to match the requirements of the plant to the site increases the survivability, performance, and longevity of the plant selected.

The first step in assessing the condition of the planting site is to examine the soil. Is it sandy and well drained? Is it moist with some organic material? Is it heavy clay and, therefore, wet and perhaps compacted? Construction practices such as cutting and filling, installation of underground utilities, and backfilling against foundations can create great diversity in soil structure. This variability can change drastically with depth and between planting locations on the same property-investigate each planting site.

Soil texture and drainage are closely related. Sandy soils usually are very well drained, have large pore spaces, and poor water-holding capabilities. They are usually associated with dry conditions. Conversely, clayey soils have much smaller pore spaces, are poorly drained, and can suffocate plant roots. The pore spaces in soil are very important to plant growth because the oxygen that occupies them is essential to healthy roots. A tree planted in poorly drained soil will be slow to establish, lack vigor, and often will slowly die.

Because plant roots require both moisture and oxygen for growth, soil drainage should be checked before planting. A poorly drained soil, high in moisture but low in oxygen, prevents both proper root development and growth of beneficial soil micro-organisms that are responsible for decomposing organic matter and releasing plant nutrients.

To test for soil drainage, dig a hole 18 inches deep, fill it with water, and let it stand overnight. If the water has not drained by morning, there is a drainage problem. (Do not test the drainage in this manner after heavy rainfall or before the ground has thawed in the spring.)

If soil drainage is inadequate, species that are tolerant of poorly drained soils may be planted, or soil drainage may be improved. This can be done in two ways. If a hard pan is present (a compacted, impermeable layer of soil) with an underlying layer of well-drained soil, a hole can be dug down to the permeable layer to provide drainage for the planting hole (Figure 1). If the soil is poorly drained and there is no well-drained layer below, a tile system can be laid (Figure 2). This, however, is expensive and requires the assistance of a professional for proper design. Simply adding gravel to the bottom of the planting hole will further decrease oxygen availability to the root system.

Compaction of the soil by vehicles or people can reduce pore space and restrict water infiltration, as well as cause physical damage to roots of existing trees. In compacted soil, oxygen is depleted, carbon dioxide accumulates, and root penetration is reduced. This is detrimental to root growth. Aerating the soil will help correct the problem.

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Planting and transplanting trees and shrubs : Yard and ...