type of insurance do we need? I guess it would be in case of damaging anything in the owners yard

With four lawns per week take your time and you really do not need the insurance yet, but if you feel you do then liabilty insurance is what you need. Make sure you go with lower amts of coverage but make sure you read the full coverage and all riders before signing making sure it does cover you for cutting down (rare plants ect) Have fun with your biz.