woody plants

Just like turf, trees and shrubs are healthiest when the soil in which they are growing has sufficient nutrients and conditions to promote root development. With cooler temperatures and seasonal rainfall, roots of woody plants tend to grow at a higher rate in the fall than in the summer. This new fine root development allows for an increase in water and nutrient uptake. Nutrients taken up in the fall months are stored and ready to relocate to the leaves next spring. For this reason, fall is an excellent time to fertilize woody plants.   With concerns about the environmental impact of excess fertilizers and the high costs of some nutrients, professional arborists are promoting the use of “prescription fertilization.” This is the process of establishing goals for fertilization, collecting samples for soil and/or foliar nutrient analysis, and applying only deficient nutrients during the fertilizer application. Goals are based on what the client expects to achieve with the fertilizer. These include promoting growth, overcoming nutrient deficiencies, maintaining health, replacing nutrients lost to leaf raking and removal, and/or increasing disease resistance. Identifying goals provides direction on the type and amount of fertilization. Soil & Foliar Samples Soil samples are the most common type of analysis arborists use to determine tree and shrub nutrient needs. Soil samples are collected from the area beneath the tree or shrub crown. The depth of sampling is based on the area where fine roots are in their highest concentration—in most areas, this is the upper 6” of ...