The calla lily is one of the most elegant ornamental plants. Despite its name, the calla lily is not actually a lily. Instead it is a member of the Araceae family. However, the plant does share many of the lily’s characteristics.
A great way to add soft structure to the garden, when in flower these plants are hard to miss. Their eye-catchingly large flowers can stretch up to 2 ft above the plant’s arrow shaped foliage.
Native to South Africa, where it is surprisingly considered a weed, the calla lily is ideal for floral borders and raised beds. Flowering for about a month, from mid to late summer, the plants also happily grow in containers and can even thrive if grown as a houseplant.
As well as being an attractive plant the calla lily is also surprisingly easy to care for. Here is everything you need to know.
Elegant and attractive the calla lily makes a fascinating addition to any garden. They can also be grown in containers and as houseplants.
Warning the calla lily is toxic to pets if ingested. The plants are also considered invasive in certain conditions.
Different Varieties of Calla Lily
There are a number of varieties of calla lily available. These come in a range of different colors, heights and growing preferences. This means that whether you are growing in a large garden or in small containers you are sure to find at least one variety to suit your situation.
If you have a large space to fill, try planting a combination of varieties. This extends the flowering period and helps you to create a show stopping display.
Fire Dance is one of the showiest cultivars, producing large gold flowers with a red edge. Another reliable cultivar is Pink Melody. This plant reaches up to 2 ft in height, producing attractive pink flowers that fade to white and then green as the petals meet the stem.
Acapulco gold is an eye-catching cultivar that produces bright yellow flowers on top of dark green foliage. Reaching 24 inches in height this large flowering cultivar is also pleasingly disease resistant.
Coming in a range of shades, planting a combination of different varieties is a great way to add drama to a garden.
Reaching about 18 inches in height California Ice Dancer produces large white flowers which sit above dark green foliage. While the plant may seem understated in comparison to more exotic cultivars such as Acapulco Gold it is still an elegant addition to a garden.
NightCap produces small chalice-like flowers. When they first open, the flowers are a shade of purple. This changes to a deep wine red color as the blooms age. Similar to NightCap is the attractive cultivar, Nightlife. Producing large, dark blue purple flowers Nightlife looks particularly attractive when planted alongside a pale or white cultivar such as California Ice Dancer.
Whichever variety you choose to grow, make sure it is suitable for your growing situation.
You will find calla lily bulbs for sale in many garden stores and DIY centers. If you want a certain variety you may need to seek out a specialist nursery.
When you select your tubers, or rhizomes, choose ones that are large and plump. They should also feel firm. Avoid soft or mouldy tubers. Larger tubers produce more flowers than smaller, younger tubers.
How to Grow a Calla Lily
If planted correctly, in a favorable position, the calla lily is pleasingly easy to grow.
The calla lily does best in a full sun position. In the warmest USDA zones the plants also grow and flower in bright, indirect light or partial sun positions.Planting in an overly dark position can slow growth and discourage flower production.
While the plants like light, they do require some protection from the intense heat of the midday sun. Calla lilies that are directly exposed to the midday sun can develop scorched or burnt foliage. Flower production may also be hampered.
If you are growing as a houseplant, position the calla lily in a bright position with lots of indirect light. Keep the plants away from heating or air conditioning vents.
The best time to plant Calla lily is in the spring after the last frost has passed and the soil has warmed. The soil should be at least 65 ℉ before planting. Depending on your climate you can begin planting bulbs as early as February and continue planting until June.
An outside temperature of around 80 ℉ is ideal for calla lilies. If temperatures drop below 50 ℉ the plants may become dormant. They also like conditions to be moist and humid.
Calla lily does best in USDA zones 9 and warmer but they are considered hardy in USDA zones 8 to 10. In cooler climates, USDA zones 3 to 7 the plants should be considered as annuals or planted in containers. During the fall and winter months move the containers to a sheltered position. Gardeners in the coldest climates wishing to keep the tubers for a second year must dig up the rhizomes in the fall, before the first frost hits. They can then be stored over winter and replanted the following spring.
While the plants thrive in sunny positions they do require some shade or protection from the intense heat of the midday sun.
If you are growing indoors, mist your calla lily plants with a fine spray. You can also grow the plants on a humidity tray, such as the 9GreenBox Bonsai Humidity Tray. Placing the plants on a humidity tray filled with pebbles and some water is a great way to maintain humidity levels. Just make sure that the container doesn’t contact the water. This leads to wet soil and root rot. You will also need to regularly top up the water as it evaporates.
What Soil is Best?
Plant your tubers in loose, well-draining potting soil. White flowering varieties are semi-aquatic, meaning that they tolerate damp soil better than colorful varieties. These prefer well-draining soil.
Amend sandy soil by working in fertilizer before planting. The calla lily struggles in heavy or clay soil types because they retain too much water. If the tubers are allowed to sit in wet soil for too long they will rot. Working gravel or compost into clay soil can help to lighten it and improve drainage.
The soil pH should be between 6 and 6.5. Plants struggle in soil that is too extreme. If you are unsure what sort of soil you have, a soil test kit is an easy to use way to find out. This information can then be used to help your garden flourish. There are a number of ways to amend soil that is either too acidic or alkaline.
Finally, the calla lily likes rich soil. Working in organic matter helps to enrich the soil. In nutrient rich soil you don’t need to fertilize your plants.
How to Plant
With a shovel dig over the soil before planting. Work in organic matter such as well-rotted manure or compost before planting.
When you are ready to plant, dig a hole large enough to hold the tuber. It should be about 4 inches deep. Position the tuber in the hole with the growing tip facing up. Cover with soil. Water well.
Applying a thin layer of mulch after planting helps the soil to conserve moisture. It also helps to suppress weed growth.
If you are planting more than one tuber, space them out to a distance of about 1 ft. This gives the plants plenty of room to grow without overcrowding each other.
In favorable conditions flower stalks usually emerge within 8 weeks of planting. In cooler conditions this may take a little longer.
Planting in Containers
If you are planting in containers, you can plant the tubers undercover about a month before the last frost. If you want the tubers to flower for Easter, plant in containers in December.
A 10 to 12 inch container comfortably holds one tuber. Your chosen container should be clean and have drainage holes in the bottom.
Fill the container with fresh potting mix. You can also make your own potting mix by combining manure or bone meal or well rotted compost with general purpose soil. Plant your chosen tubers as you would in the ground and water well.
Companion planting is the process of growing plants with similar needs or preferences together. Calla lily does best with dahlias and gladiolus. This combination creates a cut flower garden that lasts throughout the summer until the first frosts arrive.
How to Care for Calla Lily Plants
The calla lily grows from a tuber or rhizome. Each summer, after flowering, the plant dies away. With a little care and, in some areas, some winter protection it then grows back the following year.
A pleasingly easy to care plant, dividing the rhizomes every few years helps to prevent overcrowding and encourage flowering.
Easy to care for, keeping the soil around the plants weed free helps them to thrive and flower.
When to Water
Don’t water your calla lily plants too frequently. The plant’s rhizomes are prone to rotting especially if they are allowed to sit in permanently wet soil.
Once established you only need to water the plants once a week, if the soil is dry. If the soil is still wet to the touch, refrain from watering for a few more days. Ideally the soil should be consistently evenly moist.
Knowing how often to water houseplants or those growing in containers can be difficult. Plants in containers need more frequent watering than those growing in the ground. A soil moisture gauge, such as the Gouevn Soil Moisture Meter, provides a reliable way to measure the moisture content of the soil.
Should I Fertilize the Plants?
Plants growing in rich soil do not require fertilization.
Fertilizing container plants during the flowering season helps to encourage more flowers to form. To bolster your plants apply a balanced fertilizer once a fortnight throughout the flowering period. Liquid fertilizers are easy to use and make. They can also be easily incorporated into a watering routine. Alternatively working in bone meal and phosphorus to the soil around the roots also helps to encourage flowering.
Avoid fertilizers that are rich in nitrogen. These encourage the plants to produce copious amounts of foliage, often at the expense of flower production.
Diluted fish emulsion is a great way to stimulate growth after the plant has enjoyed a period of dormancy. If you are leaving the plants in the soil over winter a slow release fertilizer can also be beneficial.
Applying a Layer of Mulch
Mulch around the plants to suppress weed growth. This also helps to keep the soil moist. Organic mulches break down over time giving the soil and plants an extra nutritional boost. Just remember to regularly top up the mulch.
Mulching around plants helps the soil to retain moisture and nutrients. It also helps to deter weed growth and can discourage snugs and snails.
After Flower Care
Plants growing indoors require an enforced period of dormancy. Plants growing outside experience this naturally as the seasons change.
To help plants become dormant, when flowering finishes gradually reduce your watering routine so that the soil begins to dry out. This encourages the plant to die back naturally.
Cut away any dead areas with a clean garden scissors. This is also the ideal time to repot the plant or make divisions.
Once the plant has died away move the container to a darker area.
After two or three months resume watering and return the plant to its usual position.
How to Prune
Calla lily plants don’t drop their petals. Instead the flowers roll into a tube and, often, turns green. When this happens the flowers can be cut away from the plant. This is known as deadheading and helps to keep your plants healthy.
Unlike other plants, deadheading a calla lily doesn’t encourage new flowers to form. Instead deadheading encourages the plant to its efforts into storing energy to help them survive the winter.
Allowing flowers to remain on the plant diverts the plant’s energy into forming seed pods. While the plant will flower the following year, flowering may not be as abundant as if you had removed the spent blooms.
Plants growing in containers require repotting every year to prevent them from becoming root bound.
The clearest sign that the plant is root bound, or pot bound, is roots emerging from the drainage holes in the bottom of the container. The soil around the plant may also dry out more quickly than usual and the growth habit of the plant may slow or cease.
Repotting is best done in the fall after the plant has finished flowering for the year. Before you repot gradually reduce your watering frequency and allow the foliage to naturally die back. This encourages the plant to enter a dormant period.
Within a few weeks the soil will dry out completely and the plant will have become dormant. At this point you can safely remove the plant from its container and replant in a new pot filled with fresh potting soil.
The new container should be the same size or slightly larger than the old pot. It should also be clean and have drainage holes in the bottom.
After planting you can gradually resume watering. Aim to keep the soil moist for a few days after repotting. This wakes up the plant and helps it to establish itself in its new home.
Overwintering the Calla Lily Plant
Plants growing outdoors may require some extra care to help them survive the winter.
The calla lily is considered hardy in zones 8 or 7 if you mulch or cover with a blanket. Horticultural blankets such as the Agribon Frost Blanket protects plants from frosts and freezes.
In colder climates they are best treated as tender perennials. This means that you need to provide them with some protection during the winter months. To do this, dig up tubers in the fall, before the first frost. Some growers allow the bulbs to experience a light frost so that the frost has killed the foliage. This ensures that the tuber has stored enough nutrients to survive its dormant winter period.
After lifting the tuber, brush away any remaining soil. Do not wash the tuber. Cut away most of the foliage, leave about 2 to 3 inches.
Allow the tuber to dry out for a few days in a warm, dry place. This is known as curing and allows the skin time to toughen up. This process is vital to helping the tubers survive the winter. Curing usually takes about 3 days.
Once the bulbs are dry store in peat moss in a cool, dry and dark location. An average temperature of around 55 ℉ is ideal. If you don’t have access to peat moss you can also wrap the tubers in a paper bag or newspaper.
Calla lily plants growing in containers can simply be moved indoors.
Propagating and Dividing a Calla Lily Plant
As calla lily plants grow they become large clumps. Underneath the soil, the rhizome of the plant is also growing. The larger the clump the more prone the plant is to disease. It can also struggle to flower as profusely.
Division helps to counteract this while also giving you lots of new flowers. If you don’t want to plant them in your garden divisions make great gifts to other flower loving friends and family.
The best time to divide your plant is either in late summer or fall after flowering or in late winter after the last frost has passed.
To divide, once the plant is dormant dig around it and carefully lift the tuber out of the ground with a shovel. Cut away any remaining foliage. Brush the remaining soil from the root system. This enables you to clearly see the tuber.
With a shovel or sharp knife break or cut the tuber into sections. Each section should have at least one eye. Place in a dry location and allow the separated tubers to dry. After a few days a callus will form over the cut area. Once the callus forms the tubers can be replanted.
Common Calla Lily Problems
If properly planted the calla lily is pleasingly low maintenance.
One of the most common problems is buds forming but failing to flower. This is an indication that the soil is too wet or heavy. It can also be caused by planting the tuber too deeply. A failure to flower can also be a sign that the plants are overwatered or lacking in either water or nutrients.
Drooping foliage is an indication that the tubers are sitting in soil that is either too wet or too dry. This issue can also be caused by applying too much nitrogen rich fertilizer.
Both of these issues are easily amended by either amending your watering or fertilizing routine.
Soft rot is another common issue that is usually caused by prolonged exposure to wet conditions. This causes the stems of the plant to become mushy and soft. The easiest solution is to replant in fresh soil. You can also grow resilient or resistant cultivars.
Yellowing foliage, also known as chlorosis, is a sign of nutrient shortages in the soil. Chlorosis usually means that your soil is lacking either nitrogen, zinc or iron. To discover the cause of the problem you will need to test the soil. Chlorosis can also be a sign of root rot which is caused by allowing plants to sit in wet soil.
Leaf rollers and aphids can target plants. Regularly check your plants for signs of infestation. Pests can be washed away with an application or warm soapy water or neem oil. You can also make your own insecticidal soap to keep your plants pest free.
Finally you will need to protect young plants from slugs and snails. These can quickly devastate young plants. Mulching around the plants is one way to deter the pests.
Attractive, elegant and surprisingly easy to care for, the calla lily is a reliable addition to any garden or houseplant collection.
An elegant and attractive plant the colorful calla lily is a great way to add long lasting interest to a flower bed. Surprisingly easy to care for, they also make pleasing cut flowers or houseplants.
Jen is a master gardener, interior designer and home improvement expert. She has completed many home improvement, decor and remodeling projects with her family over the past 10 years on their 4,500 sf Victorian house. She is also a passionate farmer who keeps goats, chickens, turkeys cows and pigs on her farm, and an instructor for her community’s Organic and Sustainable Farming project.