Marigolds? Not what you probably think.

Stiff-standing Dildoes did they make
and put in Earthen-Pots;
With other things, a shame to speak
made by these foolish sots;
Which when they shamelessly had done,
they threw them o’re the Wall,
Their honest Neighbour to torment,
and vex her therewithall.

The marigolds? A euphemism for little female genitalia made of cloth, which would be the “other things, a shame to speak” mentioned in the poem.

It’s complicated. Fortunately, it’s all explained at the The Hairpin.