There is more than one type of fuyō, or hibiscus mutabilis. The one you are most likely to find when you search on the web is called suifuyō. It is the type shown in the pictures below. The plant is a type of deciduous tree or shrub. It can grow to 15 feet tall and 8 feet wide. It prefers a warm climate but can grow in cooler climates, too, where it behaves like a perennial, regrowing from its roots every year. It originated in southern China, but because of its showy flower which blooms from August to October, it has been widely replanted elsewhere. It has been in Japan for over a thousand years. Because it was so popular in the American south, it is sometimes called the Confederate Rose.
The flower blooms white in the morning, starts to turn pinkish later in the day, and becomes deep pink or red by the evening. It then stays that color for 3 to 4 days before falling off. In the meantime, more flowers continue to bloom. The picture below shows the color progression of a single bloom.
Because of the color changes, it isn't unusual to see hibiscus mutabilis plants looking like this:
As interesting as that may be, the suifuyō is not this week's painting subject. This week's subject is just plain fuyō to the Japanese. Fuyō blossoms don't turn color, though there are white varieties and pink varieties. The pink varieties are called benifuyō. Its common names include cotton rose or rosemallow, drunken rosemallow (because the pink color is like the pink someone who has been drinking begins to look), and, confusing matters even further, Confederate rose.
Because of the time of year that the fuyō blooms, it is generally considered to be a fall flower.
Here is a picture of a benifuyō.
The fuyō painting below is a detail from a kakejiku (hanging scroll) by Asami Kijo (1890-1974).