Watching the seasons is fun. The forsythia blooms about six weeks before the last frost. Forsythia isn't a great cut flower, but it is a reliable herald. Within the next few days, it will be time to divide the snowdrops. The roses are breaking dormancy and should be about done with pruning, and some of the hellebores are starting to set their seed pods. Once the anthers and filaments drop, they're ready for harvest.
Different plants depend upon different signals - air temperature, soil temperature, day length, night length, and each one signals a different chore to be completed, either by the gardener or by the garden.
The first peonies tend to emerge around the same time as the forsythia, before any of the later narcissus, but well after the hellebores have bloomed. It seems, of a sudden, that everything is at this stage. There are probably two more weeks of bare root rose planting, followed by some fertilizing.
Note to self: the forsythia is open, time to start sowing main season summer flower crops into seed trays!