Evergreen yews are species of shrubs in the conifer division of plants. They can grow quite large, in excess of 25 feet at maturity, and are often considered to be small trees. Yews are commonly used in garden hedging, as windbreaks, screens and shaped into topiary forms. Like most evergreens, yews are not very heavy feeders when planted in rich soil. But they will benefit from fertilizing, particularly during their establishment years.
Feed your younger evergreen yews less than 15 years of age in the spring of each year. Fertilize older, more mature and established yews once every other year or less frequently as needed, if at all.
Apply a 20-15-15 granular or liquid commercial fertilizer formula around the drip line of the yew without applying the fertilizer immediately around the main trunk. Alternatively, use slow-release tree fertilizer spikes driven into the soil with a mallet. Apply granules or place stakes as recommended on the product labels.
Water each fertilizer application in deeply to saturate the soil. Mulch around the drip line of the yew with a 3- to 4-inch-thick layer of organic material such as shredded bark, compost, leaf mold or cocoa bean hulls. Keep the mulch several inches away from the trunk to prevent rot and continue the mulch to a foot or more past the drip line of the yew.