|I recently forced Hyacinths to bloom. Is there anything I can do to get them doormant again and rebloom come spring?
|Unfortunately, it is just about impossible to reforce these bulbs, even if you allow the foliage to regrow for months and ripen fully, then rechill and restart them.
You can try to plant them outside and hope for blooms in spring a year from now. First, keep the foliage going as best you can by keeping them in cool temperatures (around 60) and bright light and fertilizing so that the foliage can grow and refuel the bulb. Then plant it outside this spring to continue growing and allow the leaves to die back naturally.
The bulb will then (hopefully) be able to bloom next spring or possibly the year after that. Forcing is very stressfull for them so sometimes they take an extra year to come into bloom again.