By Nancy Penrose

Trees, like all living things, need nutrients to survive and grow. Trees get their nutrients from the air and soil.

There are 16 elements a tree needs to maintain its health. Three – carbon, oxygen and hydrogen – come from the air. The remaining nutrients – nitrogen, phosphorus, potassium, calcium, magnesium sulfur, iron, manganese, boron, zinc, copper, molybdenum and chlorine – are absorbed from the soil.

When there is not enough nitrogen in the soil, the photosynthesis process speeds up and turns leaves yellow. A nitrogen deficiency can also result in a more pronounced color during the fall, stunted growth, small leaves and leaf drop.

An iron deficiency can cause yellow leaves as well. The color change however, is not consistent. For example, only a single branch may have yellow leaves.

A manganese deficiency will not only turn leaves yellow, but also make them appear limp.

If there is not enough phosphorus in the soil, the tree will grow slowly. When a tree doesn’t have enough potassium, it is more likely to become diseased or damaged.

A calcium deficiency will impact the tree’s growth and cause unhealthy, thin foliage. If there is not enough magnesium in the soil, the tree’s older leaves will start turning yellow between the veins and around the edges. Other colors can also start appearing, such as red, brown or purple.

If you see any signs of nutrient deficiencies, get your soil tested by an experienced and knowledgeable tree nursery that can find the source of the problem and recommend the proper treatment and tree care. For example, nitrogen issues can be handled with proper fertilization. An iron deficiency can be corrected with sprays, root injections and surface applications.

Are you planning on purchasing any big trees? We can help you chose the right tree for your project based on soil conditions and other environmental factors. We’ll also make sure your tree gets the nutrients it need to maintain its health.

Nancy Penrose is owner of Big Trees Inc. (, (tree nursery Snohomish, WA), one of the largest Seattle tree nurserys (see Big Trees Customer Testimonials page at, specializing in large trees for sale and transplant tree service. For more tips on tree installation or care go to See our video at and connect with us on Facebook at