A plant cover apparatus includes a bag having an interior encompassed by a wall that extends from a top end of the bag and tapers inwardly to a bottom end of the bag. The bottom end includes a rim that laterally circumscribes a plant-receiving opening formed through the bag. The bag has a slot that extends vertically from the opening through the wall. The slot includes opposed margins having cooperatively interlocking parts that can temporarily be joined and separated to increase the size of the opening. The bag may be vertically suspended from a support member positioned next to the plant. An exterior perimeter of the bag may be rigid enough to help the bag maintain its shape when suspended.