Many of the plants in our landscape pattern are perennials, simply due to the low maintenance nature of such. Don’t get me wrong, I love many annuals as well, due to their vibrant colors. Perennials just take care of themselves and many will include seed pods that give you the opportunity to propogate or make more plants.
The Japanese Iris is such a candidate in our landscape collection. My mother began with this years ago and the current ones we have come from separating her ever-growing collection. This particular iris produces seed pods that have an abundance of seeds that fall out of the pods when they ripen and you have even more plants the following year.
As with all perennials you can take a spade or shovel and divide the plants, relocating them to other places to spread the wealth.