The plants are less than a foot apart. The hydrangeas bloomed before they were planted but have not bloomed since.
It’s very likely your hydrangeas are feeling a bit crowded. Less than a foot of space between them and the peonies can create competition underground where roots quietly wrestle for moisture and nutrients — and above ground, light and air movement become limited. Hydrangeas, in particular, are sensitive to crowding and root disruption, and that could be why they bloomed before planting but have since remained quiet. When transplanted, they often go into a bit of shock, and without enough room to reestablish, they’ll hold off on flowering.
While it’s possible they’ll adjust over time, giving them more space now — ideally 2–3 feet between plants — will greatly improve their odds. Fall or early spring would be the best time to move them, when the weather’s cooler and the plants are less stressed. In the meantime, watch for signs of yellowing or stunted growth, which could confirm root stress. Peonies also benefit from a little breathing room, so spacing them out may help both plants thrive in the long run.
https://www.gardeningknowhow.com/ornamental/shrubs/hydrangea
What can I do to get them to be fragrant? My grandmothers were so fragrant!
Many modern varieties have been bred more for size, color, or form than fragrance, and sadly, that old intoxicating perfume can be lost in the process.
If your peonies aren’t fragrant, it’s most likely due to the specific variety, and no amount of feeding or pruning can bring back a scent that isn’t in their genetics. What you can do, though, is make plans to add heirloom or highly fragrant cultivars next season — varieties like Festiva Maxima, Sarah Bernhardt, or Duchesse de Nemours are renowned for their scent and look nearly identical to many modern hybrids.
In the meantime, keep your current peonies healthy — well-drained soil, full sun, and a low-nitrogen bloom booster in early spring can enhance their overall vitality. But for that sweet, familiar fragrance? That might just mean making space for a few of the old souls next spring.