Mature oaks

• Mature oak tree are susceptible to insects and disease. They prefer very acidic soil. Grown properly, mature oaks do not require fertilizer, they will naturally be fertilized by the soil and other decaying natural debris. If given a protein-based fertilizer, a mature oak may develop oak wilt, a common vascular disease, or root decay. Too much protein-based fertilizer could permanently damage the tree.
  
  

Young oaks

• If you want to assist your young oak in the early stages of tree growth, you may add a protein-based fertilizer. Apply the fertilizer once in the spring-before new growth-and once in the fall before the tree begin to lose its leaves. To avoid oak wilt and other problems, do not add too much fertilizer. Follow the fertilizer instructions as well as water often. Generally, apply the fertilizer in a circular pattern under the drip line of the tree. Apply fertilizer at the rate of one pound per diameter inch of the trunk. It is also best not to trim an oak tree during the hot summer months.
  
  

Advice

• Seek advice from your local nursery if you are unsure about using a fertilizer on your oak tree or what kind of fertilizer to apply. If you have any concerns, seek out a fertilizer that has been specifically designed for oak tree since those fertilizers contain a formula that is structured to meet the exact needs of oak trees.