Answer #1 ·
Brent Wilson's Answer · This is Chris Schema's answer that I moved from the "Comment" section to here in the "Answer" section:
Rabbits love coneflowers. They are probably getting to them early evening or early morning. I had a woodchuck eating my potato vines (decimating them), I didn't spot him for weeks. You won't know for sure unless you spot the culprit (look around for tracks or poop) but rabbits do like those tasty coneflowers. You can get a spray from your friend local nursery or big-box (HD/LOWES) store, there are organic cayenne pepper mixes you can make yourself, just ask your good friend google.)