Pineapple weed (Matricaria discoidea) is closely related to chamomile and has similar medicinal actions (calms digestion, relaxes the nervous system). It has a lovely pineapple smell, and can be found growing in compacted gravel! Definitely a weed to watch out for. You could also introduce it by harvesting the dried seed heads and sprinkling the very very small seeds around gravel areas near your house.

Happy foraging!