Wilting leaves are a visible indicator that your Goat willow might be under stress. This usually occurs when the plant is not receiving enough water, or conversely, when it's been overwatered, leading to root damage. If you notice leaf wilting, check the soil moisture. For an overwatered plant, reduce watering and improve drainage. For underwatered plants, increase watering cautiously, ensuring that the soil remains moist but not waterlogged. Another potential cause could be high temperatures, which can lead to rapid water loss through evaporation, making it crucial to ensure suitable environmental conditions.