Q.Nutrients Needed for Willow Trees
What do I need to do for my willows? Their leaves are coming in a yellowish green. They are not a vibrant green. What is my soil missing? We have fertilized the lawn but are still not happy with the color of globe willow or weeping willow.

Certified GKH Gardening Expert
Most likely, it is a nitrogen deficiency. Use a nitrogen rich fertilizer. These articles will also suggest other possibilities:
https://www.gardeningknowhow.com/plant-problems/environmental/plant-leaves-turn-yellow.htm
https://www.gardeningknowhow.com/plant-problems/environmental/leaf-chlorosis-and-iron.htm

fish emolision work wonders on willows, working some fresh peat into the top inch of the soil, and some liberal watering .
it's what my grandpappy does