Calla lilies planted too early risk rot in cold, wet ground before they can sprout. Knowing exactly when to plant calla lilies is the difference between a stunning summer display and a soggy disappointment. This guide walks you through the perfect timing for your climate, your growing zone, and your specific goals—whether you’re planting in the ground or in pots.
When To Plant Calla Lilies
The best time to plant calla lilies depends on your local frost dates. In most regions, you should plant them in spring after the last frost has passed and the soil has warmed to at least 60°F (15°C). For fall planting, only do so if you live in a frost-free zone (USDA zones 8-10).
Understanding Your Growing Zone
Your USDA hardiness zone is the single most important factor. Calla lilies are tender perennials. They cannot survive freezing temperatures in the ground.
- Zones 8-10: You can plant calla lilies in both spring and fall. Fall planting gives you earlier blooms the following year.
- Zones 3-7: Spring planting is your only option. You must dig up the rhizomes in fall and store them indoors over winter.
- Zone 9-10: You can even plant in late winter if the ground is workable and not waterlogged.
Spring Planting: The Standard Approach
Spring is the most common time to plant calla lily rhizomes. The key is to wait until the soil is warm enough. Cold, wet soil will cause the rhizomes to rot before they can grow.
- Check your last frost date: Find the average last spring frost date for your area.
- Wait 2-3 weeks after that date: This gives the soil time to warm up.
- Test the soil temperature: Use a soil thermometer. Insert it 4 inches deep. The reading should be at least 60°F.
- Prepare the bed: Loosen the soil to 12 inches deep. Mix in compost or well-rotted manure.
- Plant the rhizomes: Place them 4 inches deep with the growing tips facing up. Space them 12 to 18 inches apart.
- Water in well: Give them a good soak after planting. Then water sparingly until you see growth.
If you plant too early, the rhizomes sit in cold mud. They may never sprout. If you plant too late, the growing season is shortened, and you get fewer flowers.
Fall Planting: For Warm Climates Only
In zones 8-10, fall planting is a great option. It allows the rhizomes to establish roots over the winter. They will bloom earlier and often more profusely the following spring.
- Plant in October or November: This gives the rhizomes time to root before the coldest weather arrives.
- Mulch heavily: Apply 3-4 inches of organic mulch like straw or bark chips. This insulates the soil and protects against light frosts.
- Water sparingly: The ground is usually moist in fall. Do not overwater.
- Expect later blooms: Fall-planted callas bloom in late spring or early summer, slightly later than spring-planted ones.
Do not try fall planting if you live in zones 3-7. The rhizomes will freeze and die. You must dig them up and store them indoors.
Planting Calla Lilies In Pots
Container planting gives you more control over timing. You can start calla lilies indoors 4-6 weeks before the last frost. This gives you a head start on the growing season.
- Choose a pot: Use a container at least 12 inches wide with drainage holes.
- Use quality potting mix: A well-draining mix is essential. Add perlite or sand for extra drainage.
- Plant the rhizome: Place it 4 inches deep with the growing tip facing up.
- Water lightly: Keep the soil barely moist until you see green shoots.
- Place in a warm spot: A sunny window or a greenhouse works well. Temperatures should be 65-75°F.
- Harden off before moving outdoors: After the last frost, gradually acclimate the plants to outdoor conditions over a week.
Potted calla lilies can be moved indoors if a late frost threatens. This flexibility makes container planting ideal for gardeners in colder zones.
Signs The Soil Is Ready
You do not need a thermometer to know when to plant calla lilies. Look for these natural signs:
- Soil crumbles easily: It should not be sticky or muddy.
- No frost in the forecast: Check the 10-day weather forecast. Temperatures should stay above 50°F at night.
- Dandelions are blooming: This is a good indicator that the soil has warmed enough for many bulbs and rhizomes.
- Tree buds are swelling: Deciduous trees starting to leaf out is another sign.
Trust your eyes and hands more than the calendar. If the ground feels cold and wet, wait another week.
Planting Calla Lilies From Seed
Growing calla lilies from seed is slower but rewarding. You need to start seeds indoors 10-12 weeks before the last frost.
- Soak seeds overnight: This softens the hard seed coat and speeds germination.
- Sow in seed-starting mix: Press seeds lightly into the surface. Do not cover them deeply.
- Keep warm and moist: Place the tray in a warm spot (70-75°F). Cover with plastic wrap to retain moisture.
- Provide light: Once seeds germinate (2-3 weeks), remove the plastic and place under grow lights or in a bright window.
- Transplant outdoors after frost: Harden off the seedlings first. Plant them at the same depth they were growing in the pot.
Seed-grown calla lilies may take 2-3 years to bloom. Rhizomes are faster and more reliable for most gardeners.
Common Timing Mistakes
Many gardeners make these errors when deciding when to plant calla lilies. Avoid them for best results.
- Planting too early: This is the most common mistake. Cold, wet soil leads to rot. Wait for warmth.
- Planting too deep: Rhizomes planted deeper than 4 inches may not sprout. They need warmth to grow.
- Planting upside down: The growing tip should face up. If you plant it upside down, the shoot has to curve around, wasting energy.
- Overwatering after planting: Calla lilies need moisture but not soggy soil. Water only when the top inch of soil is dry.
- Ignoring your zone: A friend in zone 9 may plant in February. You in zone 5 should wait until May.
Regional Planting Guides
Here is a quick breakdown for specific regions in the United States.
Northeast (Zones 5-7)
Plant in late May or early June. The soil warms slowly here. Start rhizomes indoors in April for earlier blooms.
Southeast (Zones 7-9)
Plant in March or April. Fall planting is possible in zones 8 and 9. Mulch well for winter protection.
Midwest (Zones 4-6)
Plant in mid to late May. The growing season is short. Consider starting indoors to maximize bloom time.
Pacific Northwest (Zones 7-9)
Plant in April or May. The soil is often cool and wet. Wait until it dries out a bit. Fall planting works in zones 8 and 9.
Southwest (Zones 8-10)
Plant in February or March for spring blooms. Fall planting in October is also successful. Provide afternoon shade in hot areas.
California (Zones 8-10)
Coastal areas can plant in fall or spring. Inland areas with hot summers should plant in early spring for blooms before the heat.
What Happens If You Plant Too Late?
Planting calla lilies too late in the season reduces bloom time. The plants may not have enough warm weather to flower before frost returns.
- Fewer flowers: The plants focus on foliage growth instead of blooms.
- Smaller rhizomes: They do not store enough energy for next year.
- No blooms at all: In very short seasons, you may get only leaves.
If you miss the spring window, you can still plant in early summer. The plants will bloom later in the season, but you will still get flowers.
Storing Rhizomes Over Winter
If you live in zones 3-7, you must dig up your calla lily rhizomes in fall. Store them properly so they are ready for spring planting.
- Dig after the first frost: The foliage will turn yellow and die back. Cut it to 2 inches above the rhizome.
- Clean the rhizomes: Gently brush off soil. Do not wash them.
- Dry them for a week: Place them in a warm, dry spot with good air circulation.
- Store in peat moss or vermiculite: Place the rhizomes in a box or paper bag filled with dry peat moss. Keep them in a cool, dark place (45-55°F).
- Check periodically: Look for rot or shriveling. Discard any soft or moldy rhizomes.
In spring, you can plant these stored rhizomes at the correct time for your zone.
Frequently Asked Questions
Can I plant calla lilies in summer?
Yes, you can plant calla lily rhizomes in early summer, but they may not bloom until late summer or early fall. The flowers will be fewer and later than spring-planted ones.
What is the best month to plant calla lilies in zone 7?
In zone 7, the best month is April or early May, after the last frost. The soil should be warm and workable.
How deep do I plant calla lily rhizomes?
Plant them 4 inches deep. Measure from the top of the rhizome to the soil surface. Deeper planting can delay or prevent sprouting.
Do calla lilies need full sun?
They prefer full sun in cooler climates and partial shade in hot climates. Morning sun with afternoon shade is ideal in warm areas.
Can I leave calla lilies in the ground over winter?
Only in zones 8-10. In colder zones, the rhizomes will freeze and die. You must dig them up and store them indoors.
Final Tips For Success
Timing is everything with calla lilies. Here are a few last reminders.
- Be patient: Do not rush to plant. Wait for warm soil.
- Watch the weather: A late frost can kill tender shoots. Cover plants if frost is predicted.
- Fertilize lightly: Use a balanced fertilizer once shoots appear. Do not overfeed.
- Water consistently: Calla lilies like moist but not waterlogged soil. Water deeply once a week.
- Deadhead spent blooms: This encourages more flowers and keeps the plant tidy.
Knowing when to plant calla lilies is simple once you understand your climate. Wait for warm soil, plant at the right depth, and give them consistent care. You will be rewarded with elegant, long-lasting blooms that brighten your garden from summer into fall.