Q: My curly sedge was curly for the first year but now the stems are straight as a stick! Anything I can do to make it curl up again?
A: My guess is that yours has reverted back to the straight stem form of its parents. The curly stems are slightly weaker in their growth habit than the straight stems so the straight stems have come to dominate your clump. If it has any curly stems now, you can remove the straight ones and hope the plant fills in with new curly stems. If you can only find straight stems, remove them all and wait to see what happens in summer.