Appropriately named, the spittle bug can be a real problem on a range of ornamental plants. During their nymph stage, these insects make bubbles out of the liquid they secrete, with the end result looking like soap suds (or spit) on your plant. They do this to protect themselves from predators (hide in the spittle) and to insulate themselves during cold or hot temperatures, plus it stops them from dehydrating. All very well for the bugs, but not for the plants!   

Fortunately, there are now a number of very effective organic insecticides that will control this bug. Alternatively, you can try spraying the bugs with water from your hose. Make sure it is on a high pressure and the fine setting mode. This will dislodge the bugs and with repeat applications, the problem should be solved.