Does the Symbolism art movement have a settled end date, or did it decline gradually with no fixed close?

Symbolism's own Wikipedia article gives a clear start ("Years active: from the 1860s") but no symmetric end date. Its own text states only that after the beginning of the 20th century the movement "had a major effect on Russian poetry even as it became less and less popular in France," describing an uneven fade in one country while it continued to influence others elsewhere, not a documented close comparable to the movement's own dated start.