Felidar Retreat

Felidar Retreat's second mode affects only creatures you control at the time the ability resolves, including creatures you control but that for some reason didn't get a +1/+1 counter. Creatures you begin to control later in the turn won't gain vigilance or get a +1/+1 counter.

A landfall ability triggers whenever a land you control enters for any reason. It triggers whenever you play a land, as well as whenever a spell or ability puts a land onto the battlefield under your control.

A landfall ability doesn't trigger if a permanent already on the battlefield becomes a land.