When a calla lily’s leaves yellow and collapse after blooming, the plant is usually not dying. It is going into a rest period, living off its fleshy underground root until next season. Dormancy care is mostly about protecting that root from cold and rot, not about keeping leaves alive. How much work that takes depends on where you live: a gardener in a mild climate may leave plants alone, while one in a cold climate has a fall digging job.
Signs Your Calla Lily Is Ready to Rest
After the last flowers fade, let the foliage die back on its own rather than cutting green leaves.1Gardenia. Why Is My Calla Lily Struggling? Common Issues and Solutions Those leaves are still sending food down to the rhizome, the fleshy underground root that regrows next year. Around mid-fall, once flowering has finished, stop watering.2Homes and Gardens. How to winterize calla lilies in two ways, depending on your climate When the leaves have yellowed and died, cut them back to 1 to 2 inches.3White Flower Farm. Calla Lily Care
Normal die-back looks gradual. Leaves yellow from the edges and flop over late in the season. Sudden wilting in midsummer with mushy stems points to rot rather than rest. If you’re unsure, squeeze the base: a firm rhizome is resting, while a soft, smelly one is rotting.
In cold areas, the first light frost often triggers die-back. Frost on the leaves is fine, but frozen soil can damage the rhizome, so dig soon after the leaves die and before the ground freezes hard.
While the leaves fade, the plant needs no feeding or extra care. Fertilizer at this stage only encourages soft growth the plant is trying to shed. If your pot or bed stays soggy from rain, move the pot under cover or improve drainage, because a resting rhizome in wet soil can rot.
Whether to Dig Up Callas or Leave Them in Place
Most calla lilies are frost tender, so their rhizomes are lifted and stored over winter, then replanted in spring.4BBC Gardeners World Magazine. How to grow and care for calla lilies (Zantedeschia) The exception is the white arum lily, Zantedeschia aethiopica, which is hardy outdoors in mild areas.5BBC Gardeners World Magazine. How to grow and care for calla lilies (Zantedeschia)
To work out which type you have, look at the flowers. Large white blooms on tall plants often mean white arum, and colored callas in yellow, pink, purple and orange are usually tender kinds, but some tender hybrids are white too. The plant tag or purchase record should give the species name, and if you’re unsure, treat the plant as tender and lift it.
If you leave white arum outdoors, a thick layer of mulch over the crown helps in borderline areas, and a sheltered bed near a wall adds protection. Soggy winter soil is a bigger danger than mild cold.
Gardeners in borderline areas can hedge by lifting some rhizomes and leaving others, so one cold winter doesn’t wipe out the whole planting. And if frost kills the leaves of a calla you left in the ground, that doesn’t prove the rhizome is dead. Waiting until spring to see whether shoots appear is the real test.
Callas in containers can overwinter in their pots of compost in a dry, frost-free place such as a garage, shed or porch.6Homes and Gardens. How to winterize calla lilies in two ways, depending on your climate Indoor callas can be overwintered as a whole plant.7Plantura. Overwintering calla lilies Keep pots off cold concrete on a shelf or board, and don’t water while they’re stored, since the soil should stay dry.
How to Dig and Dry Calla Rhizomes
Dig up the rhizome and gently wipe off excess soil.8White Flower Farm. Calla Lily Care Then let it sit in a warm, dry place to dry out.9White Flower Farm. Calla Lily Care Advice on how long varies: one grower suggests 2 to 3 days, while a university extension service suggests 2 to 3 weeks.10White Flower Farm. Calla Lily Care11Wisconsin Horticulture. Storing Tender “Bulbs” for Winter After drying, shake off the remaining soil and remove the dried stem.12Wisconsin Horticulture. Storing Tender “Bulbs” for Winter
Digging is where most damage happens. Start several inches out from the stems with a fork and lift from below rather than pulling on the stalks. Bruises and cuts give rot an easy way in.
Smaller rhizomes in a warm, airy room dry faster, while big, wet rhizomes from heavy soil benefit from the longer time. Stop when the skin feels papery and the soil falls away easily.
Before storing, inspect each one. Discard any rhizome that is soft, slimy or foul smelling, because bacterial soft rot spreads quickly between touching rhizomes. Label varieties now, since dormant rhizomes all look alike.
Storing Rhizomes Through Winter
Store rhizomes in a cool, dark place around 50°F.13Breck. Calla Lily Care: Planting, Watering, and Storing14Proven Winners. Growing and Caring for Calla Lily – The Ultimate Guide from Proven Winners The range of 45 to 55°F works.15Wisconsin Horticulture. Storing Tender “Bulbs” for Winter Basements, root cellars and cool closets often fit. Put a cheap thermometer there for a week first, and avoid spots near furnaces or freezing exterior walls.
Pack them in a box with peat moss or sawdust.16Proven Winners. Growing and Caring for Calla Lily – The Ultimate Guide from Proven Winners Both hold a little moisture while letting air reach the rhizomes. Use a box or paper bag with some airflow rather than a sealed plastic container, since trapped moisture is how stored rhizomes end up moldy. Set them so they aren’t touching, because one that starts to rot can spread it to its neighbors. Mist occasionally so they stay slightly damp and never dry out completely,17Proven Winners. Growing and Caring for Calla Lily – The Ultimate Guide from Proven Winners and check through the winter for mold.18Breck. Calla Lily Care: Planting, Watering, and Storing
A good stored rhizome feels firm and heavy for its size, with a dry, intact skin. Wrinkling and a light, hollow feel mean it is drying out and needs a little moisture. Soft spots, a sour smell or fuzzy mold mean it is too damp, and the damaged piece should come out right away. A small patch of surface mold can sometimes be wiped off a rhizome that is otherwise firm, but a soft area means it is rotting.
Dividing Callas While They’re Dormant
Snap off side pieces by hand or cut with a clean, sharp knife.19Your Flowers Guide. Calla lily propagation by dividing rhizomes for more plants every season Make sure each piece has at least one eye, a growing bud.20Gardening Know How. Dividing Calla Lilies – How And When To Divide Callas Then leave the pieces in a warm, dry, airy spot for a day or a few days so the cuts form a tough skin.21Gardening Know How. Dividing Calla Lilies – How And When To Divide Callas22Your Flowers Guide. Calla lily propagation by dividing rhizomes for more plants every season That skin acts like a scab that keeps rot out in damp soil.23Your Flowers Guide. Calla lily propagation by dividing rhizomes for more plants every season
Eyes appear as small bumps or knobs on the surface, often slightly paler or pinker than the surrounding skin. They’re easy to miss on a dormant rhizome, so look closely in good light before cutting. Plan each cut so the piece has a growing bud and some firm flesh around it, since the flesh feeds the shoot at the start.
Dividing just before replanting means fresh, healed cuts at planting time. Older clumps with many side pieces are the best candidates, and very small pieces may take a year before blooming. Wipe the knife with alcohol between rhizomes, and don’t cut through mushy areas; discard them instead.
Waking Callas Up in Late Winter and Spring
In late winter, repot container rhizomes into fresh potting soil and begin watering to wake them.24Homes and Gardens. How to winterize calla lilies in two ways, depending on your climate Once the rest is over, resume watering and move the plant back to its growing spot.25Gardenia. Why Is My Calla Lily Struggling? Common Issues and Solutions
Rhizomes that are firm, with plump growing buds or small shoots beginning, are ready to be potted and watered. One that is shriveled and hollow after winter may not recover, and it is better to find that out in the pot than after planting it in the garden.
For earlier blooms, pot rhizomes indoors 4 to 6 weeks before the last frost. Water lightly until shoots appear, then more, and move them outdoors only after nights stay frost free.
Set rhizomes with the bumps facing up and cover them with a few inches of soil. Don’t flood the soil before shoots show. If buds start growing in the storage box, pot them up rather than breaking the shoots off, and give them light so the shoots don’t stretch.
Why a Calla Doesn’t Bloom After Dormancy
In growth-chamber trials, plants flowered best when grown around 72°F days and 63°F nights.26Taylor & Francis Online (The Journal of Horticultural Science and Biotechnology). Temperature affects plant development, flowering and tuber dormancy in calla lily (Zantedeschia) When rhizomes grew at about 81°F days and 72°F nights or hotter, flowering the next season was suppressed.27Taylor & Francis Online (The Journal of Horticultural Science and Biotechnology). Temperature affects plant development, flowering and tuber dormancy in calla lily (Zantedeschia) A longer spell of heat also produced smaller rhizomes that stayed dormant longer,28The Journal of Horticultural Science and Biotechnology. Temperature affects plant development, flowering and tuber dormancy in calla lily (Zantedeschia) while rhizomes grown cooler sprouted earlier in storage.29The Journal of Horticultural Science and Biotechnology. Temperature affects plant development, flowering and tuber dormancy in calla lily (Zantedeschia) So a hot summer can explain a late, flowerless season even when winter care was good.
Other causes are common too. Rhizomes may have shrunk or partly rotted in storage, divisions may be too small to bloom yet, or the plant may have had too little sun during the growing season. You can’t change the weather, but afternoon shade in hot climates keeps plants cooler, and mulch keeps soil temperatures down.
A calla that has been through a hot summer may simply sprout late, so give it extra weeks in warm weather before deciding it is dead. If you dig up a nonsprouting rhizome and it is firm, it may still be alive and resting longer. A soft or hollow one is rotting or dried out and will not sprout.
Handling Calla Rhizomes Safely
All parts of a calla lily contain tiny needle-like crystals, released when the plant is cut or chewed.30Poison Control. My child ate a piece of a calla lily! Chewing causes immediate burning pain in the lips, mouth and throat.31Poison Control. My child ate a piece of a calla lily! Sap in the eyes causes pain, tearing, swelling and light sensitivity, and it can irritate skin.32Poison Control. My child ate a piece of a calla lily!
Wear gloves whenever you cut, snap or divide rhizomes, and wash your hands and tools afterward. Avoid touching your face or eyes while working, since the crystals can transfer from fingers.
If a child bites a piece, wipe out the mouth, give a drink of water, and call Poison Control for guidance. If sap gets in the eyes, rinse them with water for several minutes and call Poison Control or a doctor if pain continues.