First, create a reminders list called "Evernote" in your iOS Reminders app. Then tell Siri, "Add Evernote reminder [your note here]". This will create a new reminder in your Evernote list, which in turn will append the dictated message to a note in Evernote called "Siri Notes". The future is now!
Discover more time saving integrations for iOS Reminders and Evernote