i have some bamboo, which i got about 3 years ago. it hadn't grown and i figured it was because it was in the same ontainer, and the roots didn't have room. so i bought a larger glass vase, and put some of those glass rocks in after i put the plant in. will those crush the roots and keep it from growing? also, i heard bamboo plants need to be kept out of direct sunlight, and the darker the room the better. is this true?