From my perspective as a calla lily, the dazzling white, pink, or yellow "flower" you admire is actually a specialized leaf called a spathe, which surrounds the true, tiny flowers on the central spike (spadix). Once this spectacular display concludes and the spathe begins to fade and droop, a critical internal shift occurs. My energy focus must transition from the demanding work of reproduction—attracting pollinators and sustaining the bloom structure—to the essential task of replenishment. The carbohydrates produced through photosynthesis in my remaining green leaves will now be directed downward, not to a flower, but to my underground storage organ, the rhizome. This tuberous root is my lifeline, my pantry for the dormant period to come, and the source of next year's growth. Your actions now directly impact how well I can stock these reserves.
After flowering, it is imperative that you do not remove my foliage. While the spent bloom stalk can be cut back to the base, my leaves are now my solar panels and manufacturing centers. For the next several weeks, perhaps even a few months, I require consistent care. Please continue to provide me with bright, indirect light and water me when the top inch of soil feels dry. This is also the ideal time to offer a balanced, water-soluble fertilizer. However, it is crucial that you use a formula low in nitrogen and higher in phosphorus and potassium (often labeled as a "bloom booster" or similar). High nitrogen would encourage excessive leaf growth at the expense of the rhizome development I desperately need. This post-bloom feeding is like providing a nutrient-dense meal after a great exertion, allowing me to store energy effectively for my next cycle.
As the days shorten and temperatures drop, typically in late summer or early autumn, I will begin to show clear signs that I am preparing for dormancy. My leaves will naturally start to yellow and wither. This is not a sign of distress but a normal, healthy process. I am actively drawing the remaining nutrients from my leaves back into my rhizome. You must resist the urge to cut off the yellowing foliage prematurely. Interrupting this process would be like sealing a storage jar before all the food is inside; it would leave me weakened. Only when the leaves have turned completely yellow or brown and are easily pulled away from the base should they be removed.
Once I am fully dormant (all foliage has died back), you have two primary choices, depending on your climate. If you live in a region where the ground does not freeze hard (USDA zones 8-10), you may leave my rhizome in the ground. In this case, apply a thick layer of mulch over my planting area to protect me from any unexpected cold snaps. If you are in a colder zone, or if I am growing in a container, I require a period of dry, cool rest. You should carefully dig up my rhizome, gently brush off the soil, and allow me to cure in a warm, dry, airy place for a few days. Then, store me in a box or paper bag filled with slightly moist peat moss or vermiculite, placed in a cool (around 50°F/10°C), dark location like a basement or garage. Check on me periodically during winter to ensure I do not dry out completely or become moldy.
As winter wanes and signs of spring emerge, I will be ready to begin a new growth cycle. For rhizomes stored indoors, this is the time to repot me in fresh, well-draining potting mix, with the eyes (small growth bumps) facing upward, and place me in a warm, bright location. Water me lightly at first, increasing as you see new green shoots emerge. For rhizomes left in the ground, simply remove the protective mulch layer. With the return of warmth and light, combined with the ample energy stored in my rhizome from your post-bloom care, I will be ready to produce a new set of leaves and, in time, another magnificent floral display.
