Q: I planted a weeping willow back in the spring. At this point it has some yellow leaves, more than I think is normal. What causes this?
A: Your willows are informing you that, like all trees, they would have preferred being planted in fall. Spring-planted trees become “confused” in the warm weather right after they are put in the ground. The leaves beg for water from an incomplete root system. The roots try mightily to gather enough water but often can’t supply enough for the rapidly expanding leaves.
The result? Yellow foliage.
This summer, keep the soil slightly moist, not soggy, and apply a root stimulator fertilizer. The willow will likely recover and make lots of growth by fall.