Catalpa trees have large, attractive leaves and showy, white, yellowish, or purplish flowers. They produce long, cylindrical seed-pods with white tufts of hair at each end. The common catalpa is Catalpa bignonioides, which yields a durable timber and is widely planted as an ornamental species.

The yamabuki or globeflower is a member of the buttercup family. It grows to about 2 feet (60 cm) in height and produces, as its name suggests, ball shaped flowers about 2 inches (5 cm) across in a range of colours from yellow to orange.

Sosei is indulging in a common piece of wordplay here: iro ‘colour’ also meant ‘(sexual) passion’ and so ‘colours fading’ was used to refer to the cooling of interest after an affair.