Native Plants and Wildlife Gardens has a nice post on asters versus mums. Asters can be tall and leggy, but the post has suggestions for smaller species and cultivars. All the species mentioned are native to Virginia.
Personally, I find the high density of blooms and fall toned colors of mums unnatural and off-putting, though they do have a more natural growth pattern in subsequent years if you grow them as perennials. Since I seem to be aiming for a natural aesthetic, it sounds like I should switch to asters.