The Fall Equinox Triggers Flowering in Mirlitons
Mirlitons are a photoperiodic plant that flowers in response to the day length. They have photoreceptors in their leaf cells that detect changes in light and day length. When daylight hours become less than 12 hours, they tell the plant to initiate flowering. That happens at the fall equinox, which occurs yearly between September 21 and September 24.
There’s considerable variation–flowering can come a few weeks before or a few after the equinox. And it may depend on the latitude you live at; flowering may start later the further north you live.
Mirlitons are also thermoperiodic, meaning that an abrupt cold spell will also nudge them to flower.
The Spring equinox, which occurs between March 20 and 23, will trigger flowering in the spring.