Site Problems and Poor Soil Drainage

Junipers planted in a poor site next to a driveway

Key Points

Poor site conditions like inadequate sunlight, compacted soil, and insufficient spacing can stress plants, predisposing them to attack by pathogens or insects just after planting or many years later.
Environmental stresses like severe drought and excess rainfall, extreme temperature fluctuations, winter injury, and storm damage also play a part in plant decline.
Landscape plants often struggle and may die when planted in areas of heavy foot traffic, after a construction project is completed, in tree islands in parking lots, and in narrow beds between sidewalks and streets (referred to as hell strips”). These are situations where topsoil has been removed and soils are compacted. Planting in poorly drained or wet sites, on slopes, in close proximity to buildings that reflect heat, and planting along driveways, sidewalks, and hardscaping that restrict root systems, will all slow or prevent establishment or possibly contribute to plant decline.

Trees may exhibit poor growth and fail to become established when they are not well adapted to the site. Other symptoms include early fall color, branch or stem dieback, and overall decline.
Select plants adapted to your specific climatic zone and site conditions such as seashore, urban, or woodland areas. Proper site preparation and selection of high-quality plants can help plants adapt to a difficult site.
After site conditions are considered other post-planting tasks - mulching, watering and weed management - become important for sustained plant health.
Attempts to remove or reduce the environmental stress or correct identified site problems may alleviate the symptoms and allow the plant to recover.

Well-drained soil is recommended for most landscape plants. The free movement of water and air through the soil is critical to root health. Soils with adequate organic matter have a large volume of pore space capable of handling large quantities of water with no harmful effects to plant roots.
A standard field test to check soil drainage is done by making a hole 18-inches deep and filling it with water. The water level should drop three inches every half hour and be completely drained within 24 hours.
Help to improve poorly drained soil by adding organic matter to the entire planting bed, not just the planting hole.
For sites with poorly draining soils, choose only those species of trees or shrubs that can tolerate wet conditions. For example, some popular landscape plants, such as white pines, azaleas, rhododendrons, and yews, are very prone to root decay and become susceptible to fungal root diseases when grown on wet sites.

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