poinsettia
That depends on where you live. I live in Tennessee and also lived in Iowa and have planted and transplanted Irises in April and also in Fall. Just don't plant when it is real hot and dry.
Monsteras generally prefer to be planted in pots that are slightly larger than their current size, as they like to have room for their roots to grow. However, they do not necessarily require very large pots, as long as the pot has good drainage and the plant is not root-bound.
Cacti would have to be planted in pots and moved indoors during cold, wet weather or planted in a heated greenhouse.
Ferns can be planted outside, in hanging pots, or in wax pots. There are several different species of fern so you must make sure you find one that you would enjoy to have displayed in our around your home.
A lot of plants don't like copper. So it can kill some plants
I would use "irises."
Do not allow irises to become too crowded in your garden because the irises will flower poorly or not at all.
There are around 300 species of irises, which belong to the genus Iris. These plants are commonly classified into several categories, including bearded irises, beardless irises, and bulbous irises. Each category encompasses various species and hybrids, contributing to the diversity of colors and forms found in irises.
Vincent van Gogh painted 'Irises'
William Rickatson Dykes has written: 'A handbook of garden irises' -- subject(s): Irises (Plant), Irises (Plants) 'Irises' -- subject(s): Iris (Plant), Irish
Yes, usually called Vase with Irises.