All plants require a wide variety of nutrients in varying amounts, essential nutrients required in larger quantities and make up a larger portion of the plant are called “macronutrients”, essential nutrients required in smaller amounts and makes up a smaller portion of the plant are called “micronutrients”. A lack of either of these will constitute a nutrient deficiency and may cause stress in your landscape plants which may produce visually diagnostic symptoms. Nutrients will also either be mobile, moving from one part of the plant to another, or immobile, this distinction will dictate where symptoms of deficiency will appear.
Diagnosing nutrient deficiency in your landscape plants can be very challenging. The first step would be ruling out other possible issues such as; insect problems, disease, drought stress or winter damage. Your arborist will be able to help make the distinction for you and confirm a nutrient deficiency if present, then prescribe a treatment plan. But, to arm yourself with knowledge there are some visual symptoms you can monitor and help keep your plants in good health.
- If symptoms start first present on older leaves and then spread to the rest of the plant, leaves are pale green, yellow or brown, lower leaves are dry and yellow, your plant may be lacking in nitrogen and/or phosphorus.
- If symptoms are only on older leaves, they are yellowing at the edges but remain green in the middle, or leaves are wilted or scorched or have necrotic spots or edges, your plant may be lacking in magnesium and/or potassium.
- If young or new leaves are yellowing between leaf veins and stems are shortened or rosetted your plant may need zinc, if stems are not shortened or rosetted but there are necrotic spots your plant may require manganese. If there is neither shortening and rosetting nor necrotic spots, you may have a deficiency in iron.
- If young or new leaves are yellowing entirely and spreading to the rest of the plant the issue may be a scarcity of sulfur.
- If young or new leaves are deformed and/or necrotic and the terminal bud is dying, there may be a lack of boron. If the terminal bud is not dying but leaf tips and edges are necrotic your plant may not be getting enough calcium. If the terminal bud is not dying but the plant appears stunted, with bluish-green leaves that are small and deformed, there may be a copper deficiency.
This key and visual symptom identification cannot replace tissue or soil tests or the getting the professional advice and evaluation from your arborist. Please contact your arborist at the first sign of any possible deficiency or with any concerns that you may have with your landscape plants.
(Dr. Geoffrey Denny and Dr. Karl Krouse, Mississippi State University Extension Service, “Diagnosing Nutrient Deficiencies
in Ornamental Plants”, Publication 2760, 2013).