If they are in a pot they are becoming root-bound and they are so energetic they will actually take up all soil and nutrients in a short time, feed with a liquid fertilizer, if in a pot, put it in the ground, they are very hardy, an evergreen in some states and can become very invasive in yard. I live in zone 8 in the U.S. And they multiply like crazy, give them lots of room to grow, also, depending on soil, they will change colors from year to year, depending on nutrients in soil.
