why does my pachandra have ferns growing out of it ?
It is very likely that some fern spores made it into the same area. Since ferns grow from spore instead of seed, it is very likely to spread where it is not intended. If the plant were outside for any time, there is a good chance fern spore made it in. Here is an article that will help: https://www.gardeningknowhow.com/houseplants/ferns-houseplants/propagating-ferns.htm