蒲 - bullrush, flag, cattail

dandelion (esp. species Taraxacum platycarpum)

Japanese iris; blue flag; Iris ensata

purple willow

kabayaki; loach or eel dipped and broiled in soy-based sauce

aromatic cane; orris

delicate health; fragile health

bulrush mat

(of a choice) one being as excellent as the other; both so beautiful it is hard to choose between

Iris ensata; Edo Japanese iris

Typha orientalis

rose apple (Syzygium jambos); Malabar plum; jambos

something that comes too late to be useful; iris (blooming) on the 6th (i.e. one day too late for the Boy's Day celebration)