French Sorrel Growth and Ethics

My sorrel plants are nine years old and I'm wondering if they are nearing the end of their natural lifespan. I'm not really sure how long they keep producing but they've turned into a pretty gnarly looking clump and I'm wondering if this spring I should divide the plants up and try to re-plant sections of them or let them seed this summer and then start the process over. I always cut the seed stalks off (saving some of course!) because many years ago I let them drop seed and it became a bit of a nuisance. Now to the ethical part of my question; I'm wondering if letting them go feral in a PNW food forest is a wise plan. When they self-seeded and took over my garden, I had a city plot with just a few raised beds. Now I have 3 acres, part of which is a forest garden.  I don't want to be irresponsible but I love sorrel and would love to not have to mess with cutting off the seeds all the time and having it just be part of the ecosystem here.  Thoughts?