Young or old, trees need nutrients. While your trees and ornamental don’t need to be fertilized as often as your lawn they don’t need to be on a forced diet and left to fend for their own either. Over the last few years we have seen too little water (rain) and some extreme temperatures , both high and low and while you wont see immediate response to these stresses they do show up over time in the decreased vigor of the plant making them more susceptible to disease and insect damage. Over time this will result in a general decline of the plants and possibly death necessitating replacement.
Regular (annual) root injections of a balanced (20-20-20) fertilizer with micro-nutrients will help your plants recover more quickly .
Your trees and ornamental represent a big investment that keeps adding value to your property IF you keep them in good shape.
A regularly scheduled insect and disease treatments and an annual deep root feeding is good for your investment.