Minnesota’s harsh winters make indoor starting necessary, with outdoor planting in late May. The best time to plant calla lily in minnesota is after the last frost, typically around late May to early June, when soil temperatures reach at least 60°F.
Calla lilies are tropical plants that can’t survive freezing temperatures. In Minnesota’s USDA zones 3-5, you must start them indoors or wait until the ground warms up.
Understanding Calla Lily Growth In Minnesota
Calla lilies (Zantedeschia) grow from rhizomes, not true bulbs. They need warmth and consistent moisture to thrive.
In Minnesota, the growing season is short. You have about 120-150 frost-free days, which is enough for calla lilies if you start them correctly.
Key Temperature Requirements
- Soil temperature must be above 60°F for planting
- Air temperature should stay above 50°F at night
- Frost will kill foliage and damage rhizomes
- Optimal growth happens between 65-75°F
Best Time To Plant Calla Lily In Minnesota
Now let’s get specific about timing. The best time to plant calla lily in minnesota is divided into two phases: indoor starting and outdoor transplanting.
Indoor Starting Timeline
- Mid-March to Early April: Start rhizomes indoors in pots
- 6-8 weeks before last frost: This gives plants time to develop roots
- Late April: Begin hardening off plants outdoors
- Late May: Transplant to garden beds or containers
Outdoor Planting Dates By Region
- Southern Minnesota (Zones 4-5): May 15-25
- Central Minnesota (Zone 4): May 20-30
- Northern Minnesota (Zone 3): May 25-June 5
- Lake Superior shoreline: June 1-10 (cooler microclimate)
Step-By-Step Planting Guide
Step 1: Choose Healthy Rhizomes
Buy firm, plump rhizomes from a reputable supplier. Avoid any that are shriveled, soft, or have mold spots.
Step 2: Start Indoors
- Use 6-inch pots with drainage holes
- Fill with well-draining potting mix
- Plant rhizomes 2 inches deep with eyes facing up
- Water lightly and place in bright, indirect light
- Keep soil moist but not waterlogged
Step 3: Harden Off Plants
About 2 weeks before transplanting, start acclimating plants to outdoor conditions. Place them outside for 1-2 hours on mild days, gradually increasing time over 10-14 days.
Step 4: Prepare Garden Soil
- Choose a spot with full sun to partial shade
- Loosen soil to 12 inches deep
- Mix in 2-3 inches of compost or aged manure
- Ensure soil drains well; callas hate wet feet
- Test soil pH; aim for 6.0-6.5
Step 5: Transplant Outdoors
- Dig holes 4-6 inches deep and 12-18 inches apart
- Place rhizomes with eyes facing upward
- Cover with soil and water thoroughly
- Add 2-inch layer of mulch to retain moisture
- Water deeply once a week if no rain
Calla Lily Care Throughout The Season
Watering Requirements
Callas need consistent moisture. Water when the top inch of soil feels dry. During hot spells, you may need to water every 2-3 days.
Fertilizing Schedule
- Apply balanced liquid fertilizer (10-10-10) every 2-3 weeks
- Start fertilizing after first leaves appear
- Stop fertilizing in late August
- Use slow-release granular fertilizer at planting time
Mulching And Weed Control
Mulch helps keep soil cool and moist. Use organic mulch like shredded bark or straw. Keep mulch 2 inches away from stems to prevent rot.
Deadheading Spent Blooms
Remove faded flowers to encourage more blooms. Cut the stem back to the base of the plant. This keeps energy focused on new growth.
Common Problems In Minnesota
Late Frost Damage
Even after May 25, a surprise frost can occur. Cover plants with frost cloth or old sheets if temperatures drop below 40°F.
Overwatering Issues
Minnesota’s clay soils can hold too much water. If your soil is heavy, plant callas in raised beds or containers to improve drainage.
Pest Problems
- Aphids: Spray with insecticidal soap
- Slugs: Use beer traps or diatomaceous earth
- Spider mites: Increase humidity and use neem oil
- Thrips: Remove affected leaves and use sticky traps
Disease Prevention
- Root rot: Ensure good drainage and avoid overwatering
- Botrytis blight: Improve air circulation and remove infected leaves
- Bacterial soft rot: Plant in clean soil and avoid wounding rhizomes
Growing Calla Lilies In Containers
Containers are ideal for Minnesota gardeners. You can move them indoors if weather turns cold.
Container Selection
- Use pots at least 12 inches wide and 10 inches deep
- Ensure pots have drainage holes
- Choose light-colored pots to prevent overheating
Container Planting Steps
- Fill pot with quality potting mix
- Plant rhizomes 2-3 inches deep
- Water thoroughly after planting
- Place in full sun to partial shade
- Fertilize every 2 weeks during growing season
Overwintering Container Callas
Before first frost, bring containers indoors. Cut back foliage and stop watering. Store in a cool, dark place at 50-55°F. Rhizomes will go dormant until spring.
Overwintering Calla Lily Rhizomes
In Minnesota, calla lilies are not winter-hardy. You must dig up and store rhizomes each fall.
When To Dig Up Rhizomes
Wait until after first frost kills the foliage, usually in October. Dig carefully to avoid damaging rhizomes.
How To Store Rhizomes
- Gently remove soil from rhizomes
- Let them dry in a warm, airy place for 1-2 weeks
- Cut off dead foliage and roots
- Dust with fungicide powder (optional)
- Place in peat moss, vermiculite, or paper bags
- Store at 50-55°F in a dark, dry location
- Check monthly for rot or shriveling
Spring Preparation
About 6-8 weeks before last frost, remove rhizomes from storage. Inspect for damage and discard any that are mushy. Soak in lukewarm water for 2 hours before planting.
Varieties Best Suited For Minnesota
Hardy Calla Lily Varieties
- Odessa: Deep purple, grows 24-30 inches tall
- Flame: Orange-red with yellow edges, 18-24 inches
- Picasso: White with purple center, 20-24 inches
- Black Magic: Dark burgundy, 24-30 inches
- Captain Reno: Yellow, 18-24 inches
Dwarf Varieties For Containers
- Little Suzie: Yellow, 12-15 inches
- Pink Melody: Pink, 12-15 inches
- Mini White: White, 10-12 inches
Companion Planting Ideas
Plant calla lilies with other moisture-loving plants that have similar needs.
Good Companions
- Hostas (shade-tolerant varieties)
- Astilbe
- Ferns
- Impatiens
- Begonias
Plants To Avoid
- Lavender (needs dry soil)
- Succulents (prefer arid conditions)
- Rosemary (drought-tolerant)
Frequently Asked Questions
Can I Plant Calla Lily Bulbs In Fall In Minnesota?
No. Fall planting is not recommended because rhizomes will freeze and die. Always plant in spring after frost danger passes.
What Is The Latest Date To Plant Calla Lilies In Minnesota?
You can plant calla lilies as late as mid-July, but they may not bloom before frost. For best results, plant by early June.
How Deep Should I Plant Calla Lily Rhizomes?
Plant rhizomes 2-3 inches deep. In heavy clay soil, plant slightly shallower to prevent rot.
Do Calla Lilies Need Full Sun In Minnesota?
They prefer full sun but tolerate partial shade. In hot summers, afternoon shade helps prevent leaf scorch.
How Long Do Calla Lilies Bloom In Minnesota?
With proper care, they bloom from late June through August. Deadheading extends the blooming period.
Final Tips For Success
Start your calla lilies indoors on time. Monitor weather forecasts in late May for unexpected cold snaps.
Water consistently but don’t overdo it. Callas like moisture but not soggy soil.
Fertilize regularly for continuous blooms. Stop fertilizing in late summer to help plants prepare for dormancy.
Dig up rhizomes before hard frost. Store them properly to enjoy calla lilies again next year.
With careful timing and proper care, you can enjoy elegant calla lily blooms in your Minnesota garden from summer through early fall. The key is respecting the plant’s tropical nature and working within our short growing season.
Remember that microclimates matter. South-facing slopes warm up faster than north-facing ones. Urban gardens are often warmer than rural ones. Adjust your planting dates accordingly.
If you’re new to calla lilies, start with just a few rhizomes. Learn how they respond to your specific garden conditions. Then expand your collection in following years.
Container growing offers the most control. You can move pots to catch sun or avoid frost. This flexibility is valuable in Minnesota’s unpredictable spring weather.
Don’t be discouraged if some rhizomes don’t survive storage. It happens to experienced gardeners too. Buy fresh rhizomes each year to supplement your stored ones.
With these guidelines, you now know exactly when and how to plant calla lilies in Minnesota. Follow the timeline, prepare your soil, and enjoy these stunning flowers all summer long.