The spelling of the word "crawleyroot" is a bit tricky. Phonetically, the word is pronounced /ˈkrɔːliˌruːt/. The "crawley" part is clear enough, but the "root" part is where it gets tricky. It's spelled with an "o" instead of a "u" because it's a variation of the word "rout," which itself comes from the Middle English word "route." Essentially, the "o" is a holdover from the older spelling, which is why it may seem odd to modern readers.