Insertion of phrases

[Xinfu]

p.134 But should Bortz have exfoliated the mere words so lushly, into such unnatural roses, under which, in whose red, scented dusk, dark history slithered unseen?

Do you think 'in whose red, scented dusk', is an insertion that is very uncommon in English?

What does whose refer to?

[Rusty]

Yes, it's an insertion that is uncommon. The whole sentence is hard to understand.
I would suppose 'whose' is referring to the roses.

[Xinfu]

Excellent answer. Thank you.