According to Wikipedia, styrax is a genus of about 130 species of large shrubs or small trees. The common name of snowbell gives an indication of the flowers which, as you probably guessed, are bell-shaped, pure white, and hang on long stalks along the branches.
Styrax japonicus, growing thirty feet tall and nearly as wide, is the most commonly encountered. But for those of us without space for an arboretum or ten acre woodland, S. wuyuanensis is its little brother, only reaching ten feet.
Although they tolerate part shade, styrax flower better in a sunny position, although the display only lasts three to four weeks. They enjoy good living in a soil that is neutral to acid, fertile, moist, well-drained and humus-rich, but are untroubled by pests or diseases. The elliptic-oblong, glossy, mid-green leaves have a minutely toothed margin, and turn yellow in autumn.
From my limited experience (my shrub only having been planted five years ago), flowering display depends on the previous summer. After a gloomy, overcast one, the display is limited, but after a record-breaking one such as we experienced in 2018, the styrax disappears in a cloud of white bells. Enjoy it while it lasts as, like snow in England, it will soon be gone.