Nandina shrubs, a member of the barberry family, can grow up to 10 feet tall depending on the variety. The shrub provides evergreen foliage on canelike growth and attractive berries in the fall. Although nandina is highly ornamental, it only requires minimal fertilization to thrive year-round. It can tolerate low fertility or no fertilization when grown in rich soil, but most nandinas require minimal fertilization to continue to put on new growth and produce the most attractive foliage.
Begin fertilization in late winter or early spring when the nandina begins showing new growth. Make three to four applications annually, spacing the applications two months apart from spring until fall.
Apply a balanced slow-release fertilizer, such as a 20-20-20 or 10-10-10 blend. Use the lowest fertilizer amount recommended on the package for the size of your nandina shrub.
Sprinkle the fertilizer in a ring around the trunk. Space the fertilizer ring approximately one foot out from the base of the nandina shrub.
Water the nandina thoroughly after each fertilizer application. Immediate irrigation helps dilute the fertilizer so it quickly seeps into the shrub's root zone.
Alkaline soil causes chlorosis, which results in weak or yellowed nandina foliage. An annual application of an iron sulfate spray, following package application instructions, corrects this issue.