I think the problem might be that song sparrows (at least on my property) seem to like the same type of shrub that house sparrows like. In my experience, the song sparrows like trees and deciduous shrubs as opposed to evergreens.
They definitely like less tidy spaces.......but then so do house sparrows! Wish I could help you more. Good luck.
P.S. Do you feed the birds? I've learned to never have millet in any birdseed I put out, since they like it so much. Actually, I quit feeding the birds because of a coon problem, and I have lots less house sparrows around.....so you might consider stopping birdfeeding for awhile.

Song Sparrows typically nest on or close to the ground in thick shrubbery with an understory of grasses or forbs. They will locate their nest at the base or in the low branches of shrub tangles where it is concealed in grasses. They rarely elevate their nest high in a shrub. Thus, nice tidy yards rarely attract them for nesting.

BN

Thanks both for the tips!
Yes, catherinet, I still scatter-feed with white millet, from late fall to late spring. Normally, this practice attracts us myriads of various sparrows (not to mention the resident cardinals). But this year seems incredibly dull, with just two or three Foxes and Juncos only about a month ago... Here, according to my personal notes, is past the "spring sparrow apex" now, and all is still so quiet!
So maybe I will reconsider the white millet (expensive for me to get) scattering for sparrows in the future, since obviously the HOSPs also like it so much.

I have large multi flora roses, the wild ones with all the thorns, they are always in these. So instead of cutting them all down I left some for them to nest in.

Good Luck