Japanese kerria produces an abundance of flowers over several weeks in spring (later than forsythia)....
David Beaulieu
Picture of a bloom from the shrub, Japanese kerria.
Japanese kerria's stems grow 3–6 feet in height (the shrub grows to a width that's also about 3-6 feet). These stems are bright green in color and remain so during the winter. Yellow "button" flowers dot the stems, as shown in the photo above.