by: Anthony C. Arnoldi, Board-Certified Master Arborist WI-0102B
Trees have had had their share of problems this year.
- They have had to suffer from diminishing root systems during the last2 and a half years of the long, accumulating drought,
- wood boring insect numbers have risen to extremely high levels and are attacking various tree species,
- chlorosis (yellowing due to decreased chlorophyll levels in the leaves) has begun or intensified on susceptible trees,
- needle diseases and needle drop of evergreens are commonly visible,
- fungal leaf spot diseases of deciduous trees are noticeably high and causing defoliation,
- root rots have affected many root systems to some degree,
- dieback and decline has started on a lot of trees because of these problems, and
- bad “pruning” from storms, well-intentioned homeowners or unschooled arborists has added injury to insult.
All these things, working together in varying combinations, have left our trees stressed, vulnerable to further insect and disease attack, and in less than ready condition to endure another long winter.
One of the most powerful tools arborists have at their disposal to help trees recover from stress and damage is fertilization. It is often necessary to help trees by controlling insect or disease attack, but as far as providing help that actually improves tree health and vigor, fertilization is the cornerstone.
Several options of fertilizer formulation enhance our ability to help your trees recover and avoid potential problems:
- Polymer-based nitrogen in a specially balanced complete fertilizer. This allows us unmatched control in dosing correctly and completely for an entire year without “pushing” the tree or stimulating unwanted growth. This provides the necessary elements for growth, defense, replacement leaves or roots and compensating for physical and environmental stresses.
- Root biostimulant and humates based option for tree fertilization. This enables the roots to be primarily targeted, which is often necessary to compensate drought, construction damage and root rot damage. It is invaluable in assisting trees without stimulating key root rot, vascular, fungal shoot blight or other diseases, such as Verticillium wilt, Phytopthora, Sphaeropsis, or Fireblight. It can also help to avoid attack by specific insects by avoiding nitrogen. It is indispensable in encouraging newly planted trees to become established, especially in our difficult, heavy, clay-based soils.
- Combining root biostimulant combinations with varying levels of complete fertilizer. This provides for special applications and requirements based on tree condition and insects and/or diseases present.
- Chelated iron, alone, or as an inclusion to Spring or Fall Fertilization, can help to fight or prevent chlorosis from soil deficiency.
- Manganese can also be used alone or as an inclusion to help fight this unique micronutrient deficiency.
Your Certified Arborist is best qualified to choose the right options and combinations to design the program tailored for your specific situation and avoid helping tree enemies.
He or she also directs changes in this program as required to maintain optimum tree health. This is a prime element in the Plant Health Care System of care. Fall is the perfect time to fertilize because roots naturally peak their growth as the leaves shut down for the year. Fall Fertilization can enhance this peak and promote greater pick up of the soil-injected materials. This will better prepare your tree for a long winter and help it to be able to successfully “wake up” next spring!