You can test your soil for good drainage before you plant. Dig a hole that is 1 ft (0. 30 m) square. Fill the hole with water and then let it drain completely. Once it drains, refill it again, and use a ruler to measure the water’s depth. Measure again after 15 minutes to see how much water has drained, and then multiple that amount by 4 to see how much water would drain in 1 hour. If the hole drains at a rate of 1 in (2. 5 cm) to 6 in (15 cm) per hour, you have good draining soil.
You should also make sure the roots, which grow pretty close to the surface, won’t extend under a patio or any sidewalk. Keep in mind that your neighbors might have underground utilities on their property. When you’re choosing your place for planting, don’t threaten their utilities, either.
Keep in mind that the roots of the willow can grow up to 45 ft (14 m) out from the base of the tree. You should plant the tree so that the roots will be able to extend fully before reaching the water.
Don’t add any fertilizer to the hole at this step. It will encourage the roots to grow in a circular direction around the root ball, and weeping willows grow best when their roots branch out.
If you notice the soil turning brown or a lot of leaves falling from the tree during the spring and summer, increase your watering frequency.
