Why did Martha Graham call part of her career her period of long woolens?

Martha Graham referred to the decade following her 1927 concert as her "period of long woolens" because of the plain jersey dress she wore in many of the dances she performed during that time.1

This era marked a departure from the exotic costumes and rich staging of her past work with Denishawn. Instead, her performances became characterized by a stark, original style that critics initially found obscure and "ugly," contrasting sharply with the lyrical and graceful reputation she had previously held.1