Bird and Squirrel Netting

• Netting that's specially made to keep birds, squirrels and other creatures away from your plants can help protect your hibiscus. These nets, made of polypropylene, are difficult for squirrels to chew through. Cut a piece of netting large enough to completely cover your plant. Loosely drape it over the hibiscus, then gather the ends at the base. Secure the ends with zip ties.
  
  

Caging

• Chicken wire can be used to enclose plants.wire mesh image by jimcox40 from Fotolia.com
  
  Chicken wire or other animal-proof wire and fencing can be used to keep squirrels and other animals away from your hibiscus if it is still relatively small. Hammer tomato stakes into the ground a few inches away from your hibiscus, forming a square or triangle around your shrub or group of plants. Be sure not to damage any roots in the process. Wrap the chicken wire around the stakes, securing the wire to each stake with zip ties. Squeeze the top closed and tie that shut with zip ties as well to keep squirrels from jumping inside the caged area.
  
  

Fox Urine

• While it may sound strange, fox urine can be used to repel squirrels. It is commercially available in a spray or powder -- no need to keep a fox on hand. Simply spray the urine, or sprinkle the powdered form, around your plants to deter squirrels from going near that area. Like other scent-based repellents, fox urine will need to be reapplied after rain.
  
  

Castor Oil Extract

• Castor oil extract, available under commercial names such as Whole Control, is used to keep squirrels and other small animals from digging up lawns and gardens. The oil is sprayed over garden items that squirrels may otherwise eat. One taste and the squirrel will get a bit of an upset stomach, never going near those tasty garden plants again. Castor oil is completely non-toxic and biodegradable. It is not effective against squirrels digging to bury nuts.
  
  

Dogs

• If you yard is fenced, consider allowing your dog to patrol the area around your hibiscus, especially in the early morning and late afternoon when squirrels are most active. While squirrels are easily able to escape from most predators, a free-roaming dog can discourage the pests from the area, as they will keep to the trees to avoid the animal.