QUESTION: Is calla lily an indoor or outdoor plant? I want to add some to my collection but don’t know where to grow them. — Natalie C.
ANSWER: Calla lilies can be grown outdoors, or they can be grown in containers indoors as part of a houseplant collection. Calla lilies are winter hardy in USDA Plant Hardiness Zones 8 through 10. In other zones, they can be grown outdoors as annuals. Calla lilies are not actually “true” lilies, but they are gorgeous plants. Here are some tips on how to take care of your calla lilies, whether you grow them indoors or out.
Tips for Growing Calla Lilies Outdoors
- Calla lilies require loose, nutritious soil that drains well. You may need to amend your soil to get it loose enough to provide calla lilies with the drainage they need.
- Callas also prefer soil with a pH level between 6.0 and 6.5, slightly on the acidic side. If you aren’t sure of your soil’s pH level, check out our article How to Test pH in Your Soil.
- Give your calla lily a spot where it will get full sun, unless you live in an especially warm region, in which case the calla lilies will be grateful for partial shade.
- Plant calla lilies in the spring, once the soil has warmed enough to work in and after the danger of frost has passed in your region. The rhizome will have bumps similar to the eyes of a potato. This is where your calla lily will sprout from. Always plant calla lily rhizomes with the bumps facing upward.
- Plant calla lilies four inches deep and space the plants about a foot apart. Four inches seems deep, but it’s the perfect amount for calla lilies. Water them deeply just after planting to help the soil settle in.
- Keep the soil moist where calla lilies are growing during their growing season. When the calla lilies go dormant, stop watering them. Wait two or three months before you reinstate your regular watering schedule.
- Give calla lilies fertilizer once a month during their growing season.
- Applying mulch around your calla lilies will help the soil retain moisture and choke out weeds. Just make sure that there are a few inches of empty room between the mulch and the plants. If mulch touches the plants, it can help spread plant disease through your garden.
- Calla lilies are toxic to both humans and animals, so don’t grow them in parts of the garden where children or pets play unsupervised.
Tips for Growing Calla Lilies Indoors
- Calla lilies must have loose, nutritious soil that provides them with good drainage to grow healthy and strong. Use a potting soil meant for flowers, and always use fresh potting soil.
- Calla lilies get quite large, so make sure the container you are growing your flowers in will be large enough to hold their mature size of two to three feet tall with a one- to two-foot spread.
- When you plant your calla lily, examine the rhizome for little bumps similar to the eyes of a potato. These should face upward in the container.
- Plant calla lilies in containers at a depth of three inches, with four inches between plants if you are growing more than one calla lily. Water just after planting to help the soil settle.
- Fertilize calla lilies once a month during their growing season.
- Calla lilies like to be kept moist during their growing season, but once they go dormant, you should stop watering. Do not start watering again for two or three months.
- When calla lilies go dormant and their foliage has faded, move their containers into a darker place for the two or three months you stop watering them.
- Calla lilies are toxic to both people and pets, so make sure to keep them away from where animals or children play.
Now you know all the best ways to keep your calla lilies happy and healthy—whether you grow these stunning flowers indoors or out.