Planting and Transplanting Trees and Shrubs

The first step in assessing the suitability of a planting site is to examine the condition of the soil. Is it well-drained and sandy or does it consist of heavy, compacted clay? Construction practices such as backfilling against foundations or the installation of underground utilities can create different soil structures, which may vary in depth and between different planting locations on the same property. It is important to thoroughly investigate each potential planting site.

Soil Texture and Drainage

Soil texture and drainage go hand in hand. Sandy soils, with their large pore spaces, are well-drained but have poor water-holding capabilities, making them more suitable for dry conditions. On the other hand, clay soils have smaller pore spaces, leading to poor drainage and the potential suffocation of plant roots. The presence of adequate pore spaces in the soil is vital for healthy root growth, as they allow for the essential oxygen that roots rely on.

Planting a tree in poorly drained soil can result in slow establishment, lack of vigor, and eventual decline. Poorly drained soil is characterized by high moisture content and low oxygen levels, which hinder proper root development and slow down the growth of beneficial soil microorganisms responsible for decomposing organic matter and releasing essential plant nutrients.

Checking and Improving Soil Drainage

Before planting, it is crucial to assess the soil drainage. One simple method is to dig a hole 18 inches deep, fill it with water, and let it stand overnight. If the water hasn’t drained by morning, it indicates a drainage problem. However, refrain from conducting this test after heavy rainfall or before the ground has thawed in the spring.

In cases of poor drainage, consider either planting species that are tolerant of poorly drained soils or improving soil drainage. If there is a presence of a compacted, impermeable layer of soil known as a hardpan, with a well-drained layer beneath it, dig a hole deep enough to reach the permeable layer, allowing for drainage in the planting hole. However, if the soil is poorly drained without a well-drained layer below, building a tile system is necessary. Keep in mind that this can be costly and should be designed with the assistance of a professional, as simply adding gravel to the planting hole could further restrict oxygen availability to the root system.

Compacted Soil

Soil compaction caused by vehicles or foot traffic reduces pore space and restricts water infiltration. Compacted soil leads to depleted oxygen levels, accumulation of carbon dioxide, and restricted root penetration. These conditions can physically damage the roots of existing trees. To mitigate this issue, aerating the soil is necessary to improve its structure and allow for better root growth.

Soil pH

Soil pH measures the acidity or alkalinity of the soil. A pH below 7 indicates an acid soil, while a pH above 7 indicates an alkaline soil (7 being neutral). Calcium carbonate or lime can be used to raise the soil pH. Different plant species have optimal pH ranges for their growth. Most trees thrive in a pH range of 5.5 to 6.5. However, for areas with buried concrete or near foundations and sidewalks, it is advisable to choose plant species that can tolerate higher pH levels.

Some tree species known to be tolerant of high pH levels (greater than 7.0 but less than 8.0) include green ash, white ash, amur corktree, ginkgo, hackberry, honeylocust, and Russian olive. Evergreen trees generally perform best in slightly acidic conditions. However, there are exceptions such as arborvitae, ponderosa pine, and Colorado blue spruce, which can tolerate a slightly wider pH range of 6.5 to 7.3.

Before planting a tree or shrub, it is recommended to conduct a soil test to identify any potential pH issues or nutrient deficiencies that may affect the plant’s growth.

For more information on tree planting and gardening tips, visit Tips Tree Planting. Happy gardening!