How to prevent squirrels from eating buds& blossoms on hibiscus plants

i do not think anything is completely squirrel proof but giving them things they like to eat might help. They like apples. Dried corn. sunflower seeds some vegetables and even meat. PUT OUT LEFT OVER TAKE OUT. OLD FRUIT ALSO nuts IN THE SHELL.over ripe bananas and spray a highly scented essential oil like peppermint or eucalyptus on the plants or around that area. Good luck.

While you might find the scent of coffee delicious, squirrels don't. A light layer of coffee grounds around hibiscus plants can keep them from being the pests' next meal. Just sprinkle some fresh grounds on the soil surrounding the plants to keep squirrels away. Every two weeks, add a new layer of grounds.

http://homeguides.sfgate.com/can-use-discourage-squirrels-eating-hibiscus-plants-46102.html

I've long had this problem with squirrels in my yard as well and the only thing that worked for me is to place the potted hibiscus among thorny plants like roses or Bougainvillea

The squirrels don't tread on thorny plants for obvious reasons, so generally ignore what’s with in those beds.