When contemplating the ideal spacing for planting hydrangeas, one might wonder, how far apart should I plant hydrangeas to ensure they flourish beautifully and maintain their health? Could it be that the distance between these enchanting shrubs influences not just their growth but also their blooming potential? As hydrangeas can vary significantly in size and type, is there a general guideline or does it necessitate a more nuanced approach? Furthermore, how do factors such as soil quality, sunlight exposure, and moisture retention play a role in determining the optimal spacing? Should I consider the mature width of each hydrangea variety when planning my garden layout? Is there a risk of overcrowding if I plant them too closely, leading to issues such as poor air circulation and increased vulnerability to disease? In such instances, what is the margin of space that would best incorporate both aesthetic appeal and botanical health for a thriving hydrangea garden?