Weed or not - a lot of them in a mass under my benches in the greenhouse make a very nice display. I use to keep them removed all of the time until I saw a cluster of flowers on one a few years ago and now I refuse to pull them.
If you want to keep these "indicator plants" in the same pot be very careful. Although you may not get a lot of foliage there may be a lot of roots. These can suck all the moisture ( water ) thus starving the main plant from water & fertilizer. A lot of ferns especially rabbit ( hares ) foot can clog the pot/basket & eventually they kill the plant.