It’s a good thing that the oldest modern dance troupe anywhere started celebrating its centenary early and will continue right up to the 2026 birthday proper. There is so much of Martha Graham to celebrate. This spring, it’s her Americana. “America’s great gift to the arts is rhythm,” she wrote in 1932, and the greatest contributors have been “the Negro and the Indian,” one with “a rhythm of disintegration” and the other “of integration.” The dichotomy neatly encapsulates Graham’s own startling idiom, with its contraction and release, containment and liberation. And, with the exception of Appalachian Spring, we will have to depend on that idiom to reveal her American preoccupations, because the season’s haphazard selection of Graham pieces sure doesn’t. The non-Graham works are more promising. The delicate, delightful 1942 romantic comedy Rodeo, by Graham’s good friend Agnes de Mille, will feature a stripped down bluegrass treatment of the Copland score. The excellent former Ailey resident choreographer Jamar Roberts is also turning to American roots music, with an original score by the brilliant folk musician and Silkroad director Rhiannon Giddens. —Apollinaire Scherr