I usually use a water soluble form of N with micros ,in split applications at a lower dose rate , like peters ,etc. On potted nursery stock.
I believe multiple lower doses spread over some time is more effective, less stress on plants , hedges you loss to leaching…
“”Fertilizing trees dose not have to be a “ all or nothing “ affair ! “”
Even very small amounts repeated over time can be very effective.
A heavy rain after application can result in high loss to leaching.
We don’t want our fertilizer ending up in streams, and we don’t want to loose it. We can not control how much it rains, or when?
The soil needs to be moist for plants to absorb nutrients.
A injector , hose end sprayer, watering can, tank in truck ,…
Are methods I have used.
I can’t say a specific rate, other than multiple light applications over time seems to work best.
People say not to fertilize a barefoot tree at planting, this is generally good advice.
But a small ,” very small pinch “ of soluble fertilizer in a five gallon bucket of water can help. Too much is definitely bad !
Again , it’s not a all or nothing thing, but a matter of degrees.
Best to error on the side of caution. More is not allways better. !
An other idea is to foliar feed in the fall.
I believe trees reabsorbe nutrients from the leafs in the fall , before they drop. if applied a week or two before the start changing color seems good. Little worry about leaf damage ,even at high rates, they are going to fall anyway.
Can help with foliage diseases by increasing the nutrients in the leafs , making them rot better… destroying leaf diseases ,