I have grown maypops here in Utah, and technically I’m zone 7b, and maypops struggle to come back in my yard. I was surprised this last year when I found a couple sprouting plants come back from the roots toward the end of July. The plants survived, but if they don’t come up soon enough then they won’t have enough time to flower and ripen the fruit before frost. I think you will be more successful if you treat them as annuals in colder zones. I did have some flower and fruit this year, but I grew them from plants I ordered from a nursery. If starting from seed, I would start them indoors around January or February, then plant them outside around March or April, and you should get flowers starting in May to June, and then the fruit should be ripe starting around August. The fruits need heat to ripen, and once it starts cooling off the fruits can take much longer to ripen. I have a few plants in my greenhouse that I brought inside in October, that still have unripe fruit from August, still hanging on now in mid-December and probably won’t ripen for another month.
The plants are also hard to overwinter as dormant plants. I’ve tried keeping the pots in my garage and they usually end up rotting or drying out. I haven’t discovered the best way to over winter the roots.
I do know I guy who grows maypops in Maine, and he says the secret is to grow it next to your house, near the foundation, on the south side.
