If you do a search under Annabelle you will probly find instuctions on keeping them up. I haven,t grown any but mayby if you short of fenced them in with something decorative it would give them enough support to stay up after a hard rain.

I found large "lifetime" tomato cages on Amazon. I used U-staples to install them over the growing hydrangeas. My plan is for each hydrangea to grow through its cage and have the main bush supported to prevent flopping. The green coated wire of the cages blends in with the foliage and seems to support the stems and branches adequately. https://www.amazon.com/gp/product/B00EOW6S10/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1

I personally just tie a loop of nylon twine around all the branches while they're dormant and then once they try to splay under the weight of blooms + rain, it just all stays together better.