ZZ Plant Size ZZ plants can grow up to 2-3 feet tall and wide when they're in a happy, healthy environment. They won't take up too much space, so you can easily find a spot for them in your home. Peace Lily Size Peace Lilies can vary in size, depending on the specific variety. Some types can grow up to 6 feet tall, while others stay smaller, around 1-2 feet. Make sure to research the specific variety you're interested in to get a better idea of its size.