Idaho’s short growing season makes late May or early June the ideal window for planting calla lilies. Knowing the best time to plant calla lily in idaho is crucial for getting these elegant blooms to thrive in your garden before the first frost arrives.
Calla lilies aren’t true lilies, but they bring a touch of sophistication to any Idaho landscape. With their trumpet-shaped flowers and lush foliage, they are a favorite for borders, containers, and cut flower gardens. However, because they are tender perennials, they need specific timing to succeed in Idaho’s climate.
This guide walks you through everything you need to know about planting calla lilies in Idaho. From frost dates to soil prep, we cover it all so you can enjoy a stunning display from summer through early fall.
Understanding Idaho’s Climate For Calla Lilies
Idaho spans USDA hardiness zones 3 through 7, with most of the state falling in zones 4 to 6. This means cold winters and a relatively short frost-free growing season. Calla lilies are native to South Africa and prefer warm, moist conditions. They are not frost-tolerant, so planting them too early can kill the rhizomes.
The average last frost date in Idaho varies by region. In Boise and the Treasure Valley, it’s typically around mid-May. In higher elevations like Sun Valley or Coeur d’Alene, the last frost can occur as late as early June. Always check your local frost dates before planting.
Your goal is to plant calla lilies after all danger of frost has passed and the soil has warmed to at least 60°F (15°C). Cold, wet soil can cause the rhizomes to rot, so patience is key.
Best Time To Plant Calla Lily In Idaho
For most of Idaho, the best time to plant calla lily in idaho is from late May through early June. This window gives the soil enough time to warm up and avoids the risk of a late spring frost. If you live in a warmer microclimate, such as the lower Snake River Plain, you might plant as early as mid-May. In colder mountain areas, wait until mid-June.
Planting during this period allows the calla lilies to establish strong roots before the heat of summer. They will then bloom from mid-summer into early fall, often until the first frost in October. This timing also ensures you get the most out of their growing season.
Checking Soil Temperature
Before planting, use a soil thermometer to check the temperature at a depth of 4 inches. If it’s below 60°F, wait a bit longer. Cold soil slows down growth and increases the risk of rot. You can also warm the soil by covering the planting area with black plastic for a week or two before planting.
Indoor Starting For Earlier Blooms
If you want a head start, you can plant calla lily rhizomes indoors in pots about 4 to 6 weeks before the last frost. Use a well-draining potting mix and place the pots in a warm, sunny spot. Once the outdoor soil warms up, transplant them carefully into the garden. This method can give you blooms a few weeks earlier.
Step-By-Step Planting Guide For Idaho Gardens
Follow these steps to ensure your calla lilies get off to a strong start in Idaho’s unique conditions.
1. Choose The Right Location
Calla lilies thrive in full sun to partial shade. In Idaho’s hot summer areas, afternoon shade can help prevent leaf scorch. Pick a spot with well-draining soil. If your soil is heavy clay, consider planting in raised beds or containers.
2. Prepare The Soil
Loosen the soil to a depth of 12 inches. Mix in compost or well-rotted manure to improve drainage and fertility. Calla lilies prefer slightly acidic to neutral soil with a pH between 6.0 and 7.0. A simple soil test kit can help you adjust if needed.
3. Plant The Rhizomes
Dig holes 3 to 4 inches deep. Space the rhizomes about 12 to 18 inches apart. Place the rhizome with the growing tips facing up. Cover with soil and water gently. Do not overwater at this stage, as the rhizomes need time to start rooting.
4. Watering And Mulching
After planting, water the area lightly. Keep the soil consistently moist but not waterlogged. Once the plants are established, water deeply once or twice a week, depending on rainfall. Apply a 2-inch layer of organic mulch around the plants to retain moisture and keep the roots cool.
5. Fertilizing For Blooms
Feed your calla lilies with a balanced, slow-release fertilizer at planting time. Then, every 4 to 6 weeks during the growing season, use a liquid fertilizer high in phosphorus to encourage blooming. Avoid high-nitrogen fertilizers, which promote foliage at the expense of flowers.
Overwintering Calla Lilies In Idaho
Because Idaho winters are too cold for calla lilies to survive outdoors, you must dig up the rhizomes and store them indoors. This is a critical step for perennial enjoyment.
When To Dig Up Rhizomes
Wait until after the first frost has killed the foliage, usually in late September or October. Cut back the dead leaves to about 2 inches above the ground. Carefully dig up the rhizomes, being careful not to damage them.
Cleaning And Storing
Brush off excess soil and let the rhizomes dry in a warm, airy place for a few days. Remove any damaged or soft parts. Store them in a box or paper bag filled with peat moss or dry sand. Keep them in a cool, dark location around 50°F (10°C), such as a basement or garage.
Replanting In Spring
In late May or early June, take out the stored rhizomes and inspect them. Discard any that have rotted or shriveled. Replant them following the same steps as above. With proper care, your calla lilies will come back year after year.
Common Mistakes To Avoid
Even experienced gardeners make errors with calla lilies. Here are the most common pitfalls in Idaho.
- Planting too early: Cold soil and frost will kill the rhizomes. Always wait until after the last frost.
- Overwatering: Calla lilies like moisture but not soggy soil. Poor drainage leads to rot.
- Planting too deep: Rhizomes planted deeper than 4 inches may struggle to emerge.
- Ignoring winter storage: Leaving rhizomes in the ground over winter in Idaho will kill them.
- Using too much nitrogen: This results in lots of leaves but few flowers.
Container Growing For Idaho Gardens
If you have limited space or poor soil, growing calla lilies in containers is a great option. Containers also allow you to move the plants to a sheltered spot if a late frost threatens.
Choosing A Pot
Select a pot that is at least 12 inches wide and deep, with drainage holes. Terra cotta or plastic pots both work, but plastic retains moisture better in Idaho’s dry climate.
Planting In Containers
Use a high-quality potting mix that drains well. Plant the rhizomes at the same depth as in the ground. Place the container in a location that gets morning sun and afternoon shade to prevent overheating.
Care For Potted Callas
Container plants dry out faster, so check the soil moisture regularly. Water when the top inch feels dry. Fertilize every two weeks with a balanced liquid fertilizer. In winter, move the container indoors to a cool, dark place and stop watering until spring.
Companion Plants For Calla Lilies
Pairing calla lilies with other plants can enhance your garden’s beauty. Choose companions that have similar water and sun needs.
- Impatiens: These shade-loving annuals add color and thrive in moist soil.
- Ferns: Their delicate foliage contrasts nicely with calla lily leaves.
- Hostas: Large leaves provide a lush backdrop for calla blooms.
- Lobelia: Trailing varieties work well in containers alongside callas.
- Marigolds: They repel pests and add bright color.
Pests And Diseases In Idaho
Calla lilies are relatively pest-resistant, but a few issues can arise in Idaho gardens.
Common Pests
Slugs and snails love calla lily foliage, especially in damp conditions. Use organic slug bait or hand-pick them at night. Aphids may appear on new growth; spray them off with water or use insecticidal soap.
Diseases
Root rot is the most common disease, caused by overwatering or poor drainage. Prevent it by planting in well-draining soil and not watering too frequently. Leaf spot can occur in humid conditions; remove affected leaves and improve air circulation.
Frequently Asked Questions
Can I Plant Calla Lilies In Idaho In The Fall?
No, fall planting is not recommended because the rhizomes will not survive the winter. Always plant in late spring or early summer after the frost danger has passed.
How Long Do Calla Lilies Bloom In Idaho?
With proper care, calla lilies bloom from mid-summer until the first frost in October, giving you about 8 to 12 weeks of flowers.
Do Calla Lilies Need Full Sun In Idaho?
They prefer full sun but benefit from afternoon shade in hotter parts of Idaho. Too much shade reduces blooming.
Can I Leave Calla Lilies In The Ground Over Winter In Idaho?
No, Idaho’s winters are too cold. You must dig up the rhizomes and store them indoors until spring.
What Is The Best Fertilizer For Calla Lilies In Idaho?
Use a balanced fertilizer like 10-10-10 at planting, then switch to a bloom booster high in phosphorus (like 15-30-15) during the growing season.
Final Tips For Success
Planting calla lilies at the right time is the most important factor for success in Idaho. Stick to late May or early June, and always check your local frost dates. Prepare the soil well, water consistently, and don’t forget to store the rhizomes over winter.
With a little planning, you can enjoy these elegant flowers year after year. They make excellent cut flowers for bouquets and add a touch of tropical elegance to your garden. Start with healthy rhizomes from a reputable nursery, and you’ll be rewarded with beautiful blooms.
Remember, the key is patience. Wait for warm soil, avoid overwatering, and protect your plants from frost. Follow these guidelines, and your calla lilies will thrive in Idaho’s unique growing conditions.
If you have heavy clay soil, consider amending it with sand or organic matter to improve drainage. Raised beds are another excellent option. And if you’re short on space, containers work beautifully.
Happy planting, and enjoy your calla lilies all summer long. They are truly a rewarding addition to any Idaho garden.