With all due respect to my friend Mr. Telemark, I have already started putting some granular Triple-13 down on older trees. It takes a while for the fertilizer to permeate the ground sufficiently for root pickup and winter snow melt / spring rains are critical to absorption.
From the "net"
"Fertilizing a selected oak is more than a matter of scattering a handful of fertilizer at its base. There are two methods of fertilizing your selected oaks. The first is the use of 13-13-13 granular fertilizer. This
should be applied in early spring. Apply it at a rate of 2 pounds per 1,000 square feet of crown. A mature white oak with a crown measuring 80 by 80 feet, or 6,400 square feet, would require about 13 pounds of fertilizer."
"Oak trees experience a quick spurt of growth in the spring, followed by slower spurts of growth sprinkled throughout the summer and fall seasons. For the best nutrient uptake by the oak tree's roots after fertilization,
apply your fertilizer in the early spring before this initial spring growth spurt starts."
Good info ... https://www.greatnorthernregreenery.com/healthy-oak-tree-tips/
I also use water soluble on small trees or newly planted vegetation with small root structures; chestnuts and oaks really like fertilization appropriate for acid-loving plants like orchids, etc.
From ...
https://aggie-hort.tamu.edu/archives/parsons/trees/tree.html
they say ....
"When do you fertilize trees and with what?"
A: "Newly planted and younger trees should not be fertilized at planting as it can damage new roots. If soil test shows need, use liquid fertilizer; however, entire area should have fertility corrected before planting begins. Established trees in yards that are doing well do not need extra feeding. They receive adequate fertilization as lawns are fertilized using a 3-1-2 ratio fertilizer. Lush, fast growth is not strong growth. Any
heavy feeding should be in late winter for spring and summer growth; no special summer or fall feeding. "
Some of the things I use ...
View attachment 50796
