From our perspective as Calla Lily plants (Zantedeschia spp.), our watering needs are intrinsically tied to our natural growth cycle and root structure. We are not like thirsty ferns or drought-loving cacti; we are rhizomatous plants. This means we store water and energy in our thick, underground stems called rhizomes. This storage organ is both a blessing and a curse. It allows us to withstand brief dry spells, but it is also highly susceptible to rot if left sitting in constantly waterlogged soil. Our ultimate desire is for a cycle of moisture that mimics the seasonal rains and dry periods of our native habitats in Southern Africa. The key is consistent moisture during our active growth and flowering phases, followed by a period of dryness when we are dormant.
When you grow us indoors, you control the environment, so your watering habits become our entire world. During our active growing season, typically from late winter through spring and summer, we are putting energy into producing our elegant spathes (the part you call the flower) and lush foliage. At this time, we crave consistent moisture. Please water us when the top inch (about 2.5 cm) of the soil feels dry to your touch. Water us thoroughly until you see a small amount of liquid escape from the drainage hole at the bottom of the pot. This ensures our entire root ball and rhizome receive a good drink. Then, crucially, empty the saucer underneath after about 15 minutes. We do not want to sit in a puddle. As daylight shortens after our flowering period, our leaves will naturally begin to yellow and die back. This is our signal that we are entering dormancy. At this stage, you must drastically reduce watering. Allow the soil to dry out almost completely to encourage the rhizome to rest.
Life outdoors is more dynamic for us, and our watering needs fluctuate with the weather. If we are planted in the ground, our roots can seek out moisture more freely than in a pot. However, we still rely on you to supplement rainfall. During the heat of the growing season, we will likely need deep watering once or twice a week. The goal is to moisten the soil to a depth of about 6-8 inches. A light sprinkle is not sufficient; it only wets the surface and encourages shallow roots. Check the soil a few inches down—if it feels dry, it is time for a long, deep drink. If your area experiences regular rainfall, you may not need to water us at all. If we are in containers outdoors, we will dry out much faster than our in-ground counterparts due to wind and sun exposure. You may need to check our soil moisture daily during hot, windy weather and water us every other day or even daily to maintain that ideal consistently moist (but not soggy) condition.
We communicate our distress clearly if you know what to look for. Overwatering is the most common threat to our health. If our soil is perpetually wet, our rhizomes will suffocate and rot. You will see our leaves turn yellow, often starting with the lower, older leaves, and they may feel soft and mushy. The plant may wilt despite wet soil—a classic sign of root rot. Underwatering, while less immediately fatal, causes its own problems. Our leaves will become limp, droop, and the edges may turn brown and crispy. Our growth will be stunted, and we will fail to produce flowers, or the spathes we do produce will be small and short-lived. When in doubt, it is always safer to err on the side of slightly too dry than too wet, as our rhizomes give us a small buffer against drought.
