Answer: Ornamental grasses such as miscanthus normally arch gracefully as part of their ornamental form and natural growth habit. Extremely heavy rains can cause the stems to fall over, but they should be able to withstand normal rains. A few situations can cause weak stems: overfertilizing with nitrogen, lack of sunlight, or overcrowding.
Unfortunately, trimming them back does not seem to encourage thicker stockier growth. If the plants appear to by dying out in the center, plan to divide them in early spring before growth begins, placing divisions in a spot with full sun. Also, make sure you aren't inadvertantly fertilizing the plants with a high-nitrogen lawn fertilizer.
Q&A Library Searching Tips