bigleaf hydrangea blooms

Question

the blooms are so big and heavy that they won’t hold up on the plant, just fall to the ground. Help

Answer 1

It may be a soil issue that isn't allowing the roots and stems to grow strong. They like moist, rich soil. Adding compost helps.
If you can drive some narrow stakes into the soil far enough away from the plant's trunk so that you don't disturb the roots, you may be able to tie the flowering stems up with soft yarn or fabric.

https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea/mophead-hydrangea-care.htm