No, lease agreements do not need to be notarized in Vermont. Since lease agreements do not need to be signed to be valid in Vermont, notarization is completely optional. Leases are valid and enforceable regardless of whether they have been notarized or not.
The landlord and tenant can agree to notarize a written lease agreement if they wish, but it is not required by Vermont state law.
The information for this answer was found on our Vermont Residential Lease Agreement answers.