Hilchos Shemittah v’Yoveil 4:17

Onions that don’t produce scallions, Egyptian beans that weren’t watered for 30 days prior to Rosh Hashana, and onions that do produce scallions that weren’t watered for three intervals prior to Rosh Hashana are all considered sixth-year produce. If they weren’t watered for a shorter period of time, they are considered the aftergrowth of shemittah.

Hilchos Shemittah v’Yoveil 4:18

Regarding gourds that were left in the ground to produce seed, if they hardened before Rosh Hashana, making them unfit for people to eat, they may be kept during shemittah because they’re sixth-year produce; if not, they’re considered the aftergrowth of shemittah. The same is true of vegetables: whatever hardened before Rosh Hashana may be kept during shemittah, but not if they’re soft because then they’re aftergrowth. One need not uproot wild onions. Rather, they may be left in the ground “as is” and if they sprout in the eighth year, they’re permitted. Similarly, one need not uproot artichokes; all one must do is cut off the leaves (which are an edible part). If they sprout again in the eighth year, it’s permitted.