Maintaining a good fertilization program can keep your plants vigorous and help prevent diseases such
as bacterial canker and oak root fungus.
Young trees benefit from light applications of nitrogen
fertilizer. Apply about 0.33 pound of ammonium sulfate (which
equals 1 to 2 oz of actual nitrogen) per tree per year.
Keep the fertilizer at least 18 inches or farther from the
trunk and water well after application. As trees mature,
increase fertilizer to up to 5 pounds of ammonium sulfate
per tree per year (1 pound actual nitrogen). The ideal time
of application is just after bloom.
Never use more nitrogen than necessary. Nitrogen fertilizers favor leaf growth, which may encourage
insects such as aphids to build up. Be careful not to neglect other important nutrients, such as
iron or potassium,
or deficiencies will result.