By Erin Marissa Russell
Ready to learn about how to plant and care for calla lilies? These attention-grabbing flowers are tall enough to make excellent border plants. You can grow calla lilies anywhere that has moist, rich, well-draining soil, as long as the flowers get full sun or partial shade. They can even grow in bog or marsh gardens. Calla lilies can also be planted near ponds and streams.
Best of all, they’re exceptionally easy to care for. The flowers come in a staggering array of shades depending on variety, from white and yellow through pink, orange, and purple all the way to black. As cut flowers, calla lilies can last for up to two weeks.
Gardeners in USDA Plant Hardiness zones 8 through 10 can grow calla lilies outdoors year-round. (There is some variation of growing zones depending on the variety of calla lilies you are growing, so do a bit of research to make sure you get a variety that will grow well in your region.) In all zones, calla lilies can be grown as annuals. Gardeners in all regions can grow calla lilies indoors as houseplants.
Toxicity Warning: Be aware that calla lilies are toxic to people and animals, so they should not be planted where children or pets play unsupervised.
Your calla lilies will need to be planted either in full sun or in partial shade. Full sun is appropriate in cooler climates, while those in warmer regions should plant their calla lilies in partial shade. The flowers will be grateful for the respite from the summer sun in hot areas.
Choose your rhizomes carefully. The largest, firmest rhizomes will produce the tallest plants with the most stunning flowers. Each rhizome has little bumps on it, similar to the eyes of a potato. Plant the rhizome with these bumps facing up, because the calla lily will sprout from these spots.
Calla lilies need loose, rich, nutritious soil to thrive. You may wish to amend your soil with well-rotted compost or other organic material before planting your calla lilies.
Plant calla lilies in the spring, once the ground has warmed up enough to work (65 degrees Fahrenheit) and danger of frost has passed. If you choose, you can start the rhizomes inside for earlier blooms. Calla lilies can be started inside up to a month before the last forecasted frost in your area.
Calla lilies should be planted four inches deep and a foot apart. After planting the rhizomes (with the bumps facing up), cover them with soil and water well to help the ground settle. The first shoots will appear after about two weeks. You should start seeing calla lily blooms 13 to 16 weeks after the rhizomes were planted.
Calla lilies that you plant in the springtime will blossom for three to eight weeks between the middle of summer and the beginning of fall. In zones where calla lilies are grown as perennials, blooms appear from the end of spring to the beginning of summer.
Certain calla lilies from the variety Zantedeschia aethiopica can grow quite happily in water up to one foot deep. If you’re growing this variety, use aquatic compost along with a planting basket one foot deep.
Calla lilies like to stay hydrated, so keep them moist and be careful not to let the soil where they are growing dry out. However, do not keep the soil oversaturated with water, or the calla lilies might get root rot.
During the calla lilies’ growing season, fertilize the plants every two weeks with a balanced liquid fertilizer. Stop giving the calla lilies fertilizer once the growing season is over and flowers have faded.
Calla lilies will benefit from mulching to help the soil retain moisture and choke out weeds. Apply mulch every year in the fall using well rotted manure or compost. Be careful to leave a few inches of space between your plants and the mulch, as if the mulch is touching the plants it can help spread plant disease throughout your garden.
Once the blossoms fade, remove the flower stems. It is best to pull the stems instead of cutting them, as cutting can damage both the plant and the rhizomes.
If you want to use calla lilies in flower arrangements, pull them during the cool times of morning or evening. Choose flowers that are wide open with the stamens showing. As with faded flower stems, you should pull the flowers instead of cutting them to avoid damage to your calla lilies.
If you will be growing your calla lilies as annuals, you can still save the rhizomes until spring so you can plant them again. Before the first frost, dig up your rhizomes and keep them safe in a cool, dark place until time to replant them the next spring.
In springtime, you can cut these reserved rhizomes into smaller pieces, each with a bump or eye on it where the sprouts will emerge.
If you have overwintered your calla lilies outdoors in the garden, they have probably developed large clumps of rhizomes underneath the plant. Before the plant has much top growth, you can dig up these clumps and use a spade to divide the rhizomes into smaller sections for planting again.
In zones 8 through 10, calla lilies can simply be left in the outdoor garden when winter comes. In colder areas, you can dig up the rhizomes prior to the first frost in your area and keep them in a cool, dry, dark place until time to plant them next spring.
Once the calla lilies’ foliage has turned brown and the temperature in your region dips below freezing, cut the calla lilies back to one or two inches of growth. Then dig up the rhizomes to store over the winter.
Start by washing the rhizomes carefully and letting them dry. For two or three days, they should be kept in a warm, dry place where the temperature is between 65 and 75 degrees Fahrenheit. After they have cured for two or three days, move them into a box packed with peat moss that has been lightly dampened. Keep the box in a dark area that stays between 50 and 60 degrees Fahrenheit. Periodically during the winter, check the box of rhizomes to make sure they are neither too wet nor too dry.
Aphids: These itsy bitsy bugs can cause big problems for your plants. You will be able to see the tiny aphids on the undersides of foliage on affected plants. They also cause distortion, curling, or wrinkling of leaves where they have been feeding. You can make an aphid repellent spray out of one gallon of warm water, a few drops of dish soap, and a tablespoon of neem oil. For more information, check out our article All About Aphids, and How to Kill Them.
Dasheen Mosaic Virus: This disease is spread by aphids, so check your plants for the tiny insects that congregate on the undersides of leaves. Plants with Dasheen Mosaic Virus don’t grow as healthy and strong as they should, and eventually will display a pattern on their foliage that resembles a mosaic. If you suspect Dasheen Mosaic Virus, you will need to remove and discard any affected plants in your garden, as the disease can spread from one plant to another. Do not use the infected plants in compost, or you risk spreading the disease anew when the compost is used.
Powdery Mildew: Powdery mildew is a fungal disease that manifests first as spots of gray or white that have a powdery texture. You will see powdery mildew most often on the top side of leaves, the outside edge of blossoms, or the top of stems. For more information on diagnosing and treating powdery mildew, see our article Identify, Prevent, and Treat Garden Problems: Powdery Mildew Fungal Disease.
Rot: Calla lilies can fall victim to crown rot, root rot, or pythium rot. Crown rot causes yellowed leaves, pythium rot causes water-soaked lesions, and root rot causes yellowed leaf margins. You can diagnose root rot by carefully lifting the plant from its soil, gently shaking off the excess dirt, and examining the roots. If you see slimy, foul-smelling, or dark-colored roots, root rot has taken hold. The only way to cure rot is to use clean, sterilized gardening shears to cut away the affected foliage or roots. Then you must be careful not to overwater your calla lilies, as the rot diseases are caused by excess moisture. For more information, see our article How to Fight Stem and Root Rot.
Spotted wilt virus: Spotted wilt virus causes foliage to display yellow or white streaks or patches. It is spread by an insect called thrips. (You can learn more about them in our article How to Fight Thrips.) As with any virus, infected plants must be removed from the garden and discarded, but not used in compost.
Now you’ve learned all about how to plant and raise calla lilies. We’ve also discussed overwintering, propagation, and pests and diseases. All that’s left to do is choose the variety of calla lilies you will grow and plant them in your garden.