Has someone been spitting on your flowers? What is that collection of tiny bubbles surrounding that stem? If you probe beneath the goop, you’ll find one of a number of leafhopper species called spittlebugs. All leafhoppers resemble stocky, miniature grasshoppers about a quarter-inch long. They have sucking mouthparts used to puncture plant stems. Then they feed on the juices and sugars found inside.
Spittlebugs use a special pore on tip of their abdomen to bubble air though some of those juices. The result is a frothy mass that protects them from predators.
While some spittlebug species do significant damage in the eastern United States, the ones found here in Colorado are not a problem. They seldom accumulate in sufficient numbers to harm our landscape plants. If you are concerned, just rinse them off with a jet of water from the hose.