Leyland cypress (Cupressocyparis leylandii), is an evergreen tree that grows 3 to 4 feet a year until it reaches a height of 50 feet. Recognize a Leyland cypress tree by its oval shape. Although this low-maintenance tree tolerates many different types of soil, it needs fertilizer for optimal health. According to the University of Minnesota Extension, the best time to fertilize Leyland Cypress is between April and mid-July.
Measure the diameter of the Leyland cypress tree. Note the measurement in inches. This will guide you as to how much fertilizer your tree needs.
Sprinkle a time-release granular fertilizer with an NPK of 10-8-6 around the Leyland cypress tree. You will need 1 lb. of fertilizer for every inch of tree diameter. For example, a Leyland cypress tree with a diameter of 8 inches requires 8 lbs. of fertilizer.
Rake the granular fertilizer to mix it 1/4 inch deep into the soil.
Water the fertilized area of around the Leyland cypress tree. Watering the fertilizer helps it seep deeper into the soil so that it can be utilized by the tree's roots sooner.