How To Grow Calla Lilies

With soft, elegant lines of the blooms, there is no doubt that Callas lend an air of exotic romance to your garden or vase. You can add that allure to your garden! Callas hail from the warmer, wetter regions of South Africa. They need warm soil and regular watering to thrive. These tender bulbs are only winter hardy to zone 8, so they can be treated as annuals in colder climates, or brought inside over the winter. Follow our guide for helpful tips for growing these beautiful summer-blooming bulbs.

Location:

• Select a part-shade spot in an area that benefits from constantly moist soil, such as the edge of a pond, or in a container water feature.
• If planting in pots, use an organically rich potting soil that drains well but retains moisture.

Note: In zones where it can overwinter, such as in the Pacific Northwest, the white species Calla (Zantedeschia aethiopica) will not only spread but can be considered a bit of a pest. The Calla cultivars that we offer are generally considered to be well-behaved alternatives.

The sap can cause contact dermatitis in some people, so it's recommended to use gloves when planting.

Light: A partly-shaded spot protected from the most intense sun of the day is ideal, as too much direct sun on Calla leaves and flowers can burn them. We recommend at least 6 hours or more of sun each day. The plants need light to bloom well, so full shade is not a good option. 

Soil: Callas need organically-rich, heavily fertile soil that is on the moist side to thrive. Average moist soils will also be tolerated, but dry soils will not.

Spacing:

• Space rhizomes 4-6” apart when planting a clump together, and space 12-18” away from other plants.
• If planting in pots, plant 2-3 rhizomes per 10-inch pot, or one per 6 inch pot. Cover the bulbs with 1-2 inches of soil.

Planting Time:

• Plant rhizomes of Callas in the late spring, when the danger of frost is past and the soil has warmed.
• Planting Callas too early outside in cold soil will delay their growth and blooming. If you have a greenhouse or warm, well-lit area in your home, you can start the rhizomes earlier, then transplant your Callas outside when nights are warm (over 50 degrees). 

• Choose a container with drainage holes that is at least 10-12 inches in diameter. Try to have fun pairing a colorful pot with your Calla Lilies.
• Use an organic potting mix and fill the pot about halfway with soil – you’ll want the rhizomes to rest about three inches below the rim of the pot.
• Set the calla lily rhizomes on top of the soil and cover with soil up to the top of the rim, leaving about ½ inch of space.
• Water thoroughly to remove any air pockets.
• Place the container in an area – indoors or out – that receives at least six hours of sun per day.
• To get a jump start on spring growth, plant your bulbs indoors in early spring and bring them outdoors once the temperatures warm up and there is no more chance of frost.
• Water thoroughly once the top of the soil begins to dry out, making sure to soak the pot before the plant gets completely dry. This should be done several times per week, depending on the location of the container.

Growth Habit: Colorful Calla cultivars in shades from yellow to almost black to deep red are usually shorter than the straight species, from about 12-18 inches tall. In warm climates, Callas will spread into large clumps, in colder climates they must be treated like an annual or dug and overwintered indoors.

Staking: No staking is necessary.

Watering: Watering is crucial when it comes to Callas. Keep them moist from the time they are planted until after they bloom and start to die back, when you can gradually withhold water. In dormancy during the late fall/winter months they should be kept just lightly hydrated to avoid drying out, but not damp enough to encourage rotting.

Fertilizing: Rich soil is preferred when it comes to Callas. Plant in a compost-rich soil and feed with a balanced slow-release organic fertilizer during the growing season.

Mulching: Mulch can help retain moisture in the soil, and is therefore recommended. Keep mulch away from the crown of the plant to discourage rot.

Callas are only winter hardy to zone 8. If you live in a colder region, dig your Callas and bring them inside, storing them in a cool, dry place where temperatures are above freezing.

Trimming & Pruning: Calla will not re-bloom if deadheaded (spent blooms trimmed off), but old blossoms will disfigure foliage as they die back, so removing them is recommended. Many of the colorful Calla cultivars will go dormant not long after flowering.

Dividing & Transplanting: If dividing larger clumps of Calla in warmer climates, dig the clumps and gently pull them apart. Use a sharp knife to divide them and replant. If dividing smaller, overwintered pots, look for offsets in the winter or early spring, cut them apart and let the cuts callus to prevent rot. Pot them up in rich soil in the spring so they can be monitored and set out in the garden when they get bigger.

Pests & Disease: Thrips can be an issue with Callas, as can several types of bacteria rot which will affect the rhizome and the crown of the plant. Infected plants must be discarded. Fresh, clean potting soil is recommended to prevent problems with disease, as is using clean, sharp knives to divide rhizomes and letting them callus over before replanting.

Additional Note: All parts of Calla lilies are poisonous if consumed. 

• Reduce watering after your Calla Lilies have finished blooming for the season and the leaves start to turn yellow.
• Once the foliage dies back completely, cut it down to the ground.
• Dig up your rhizomes, clean them off with water and let them air dry for at least 12 hours.
• Store rhizomes in peat moss, paper bags, or a crate  – they just need to have some air ventilation – in a cool, dry area that stays at least 50 degrees.
• Come spring, re-plant using the planting steps above!

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