Can a landlord evict a person without grounds?

It depends. If the person is truly a "landlord" in that the sense that the person who he or she is trying to evict rents from the landlord, then the landlord cannot evict them during the term of a lease so long as that person honors his or her obligations under the lease. Therefore, for example, during the term of a lease if a tenant pays rent on time and does everything else the tenant is supposed to, the landlord cannot evict him or her.

However, landlords are not obligated to renew leases, unless and only to the extent there is a written lease specifying renewal under certain grounds or circumstances. Otherwise, when a lease is up, a landlord may refuse to renew it; if a landlord refuses to renew the lease, the tenant loses the right to stay there and may be evicted. If there is no written lease, then the oral lease will be a month-to-month, which means the landlord could not renew the lease on a month's notice at any time, then ask the tenant to leave.

(Note: landlords may not disciminate in housing, so they can't ask a tenant to leave based on race, religion, sex, age over 40, or disability, etc. And also, certain municipalities may have laws requiring renewals, at least in certain kinds of housing (e.g. public, rent controlled, etc.) under some circumstances, so always check local laws; your local housing dept. can help you.)

If the landlord is not really a landlord--e.g. the "tenant" is not paying rent and is not a tenant, just a friend or family member the property owner is letting stay there--then the person can be evicted at will, as long as the proper procedure is followed.