Droughts can harm plant life, but most research only looks at how severe the drought is. This study shows that how long a drought lasts and how often it happens also matter. We studied over 40 years of satellite data across different parts of the United States to understand how droughts affect the way plants grow and use water. We found that droughts starting in the dry season are more damaging than those starting in the wet season. In drier regions like the western U.S., long-lasting droughts with lower severity caused more harm than short, intense ones. These findings suggest that to better protect ecosystems, we need to consider not just how strong a drought is, but also when it starts and how long it lasts.