Weeping willow trees, known botanically as Salix babylonica, are deciduous ornamental trees grown primarily for their dramatic foliage canopies. Weeping willows thrive in moist nutrient-rich soil often near bodies of water. The trees are rapid growers and their root system is large so the trees can benefit from light fertilization each year with feeding becoming more important when the tree is growing in nutritionally deficient soil.
Feed your weeping willow once each year in the spring after the last frost has passed and the soil is warm and can easily be worked and absorb the applied fertilizer and water.
Apply a complete and balanced organic or slow-release fertilizer formula that is rich in nitrogen with a guaranteed analysis of 10-10-10 or 20-20-20. Follow the dosing directions on the product label using the recommended amount for the size and age of your tree, never applying more than the recommended dose.
Spread the fertilizer over the soil under the tree. Start at least a foot out from the trunk and extend the spread to the outer branch tips of the drip line of the tree. Nestle the fertilizer into the top 2 inches of soil with a rake or hoe, distributing it evenly.
Water the fertilizer and surrounding soil in deeply to begin to wash the nutrients down into the soil and the root zone. Drench the soil to a depth of at least 8 to 10 inches to ensure good distribution and prevent drought stress.