Answer: There are several possible caused for this to happen. Transplant shock can cause yellowing, lack of sun can cause yellowing (Hibiscus need full sun), planting too deeply can cause yellowing (plant at same depth as it grew before, no deeper), overwatering (keep the soil evenly moist like a wrung out sponge, not sopping wet) or poorly drained soil (container must have a drainage hole in the bottom; plant will not thrive in heavy clay soil) can cause yellowing. A new plant will also go through an adjustment period, during which some of the older foliage or interior foliage may yellow. If it is just a few leaves, it is not really a problem to worry about. If the entire plant is turning yellow then there is cause for concern. I hope this helps you trouble shoot.
Q&A Library Searching Tips