One shrub that speaks louder through its fragrance than its bloom is fragrant (or "winter") honeysuckle. Unlike other honeysuckle shrubs from Asia, which bloom later, I've never seen this one spread into natural areas.
The fragrance is such that a large shrub in full bloom can stop you in your tracks from 50 feet away. If you've never seen it, ask the local bumblebees and honeybees if one's growing in your neighborhood, or keep an eye out for small white flowers, and follow your nose.
A row of them grows along the nature trail loop next to the towpath, west of Harrison Street.