Do all trees and shrubs need to be fertilized?
Trees and shrubs that are young and actively growing will perform much better (see fig. 1) if they are fertilized. On the other hand, they won’t die if they have to rely on their own resources. Research as to whether or not mature plants should be fertilized is less conclusive. We do know for sure that mature trees need fertilizer and should be applied at moderately amounts and more often, as mature trees grow more slowly. High application amounts will cause rapid lush growth, the trees energy is diverted from defense to rapid growth and that rings a loud dinner bell for insects.
