When To Plant Calla Lily Bulbs In Ontario

Knowing when to plant calla lily bulbs in Ontario is the single most important step for getting those stunning spring blooms. If you get the timing right, everything else falls into place much easier. This guide will give you the clear, simple advice you need to succeed in our unique Canadian climate.

Let’s talk about what calla lilies really are. They aren’t true lilies, and those “bulbs” are actually rhizomes. But everyone calls them bulbs, so we will too for simplicity. They come in gorgeous colors like classic white, deep purple, sunny yellow, and soft pink. They love warmth and need a specific planting schedule to thrive here.

The golden rule for Ontario gardeners is to plant your calla lily bulbs after all danger of frost has passed in the spring. Callas are very sensitive to cold soil and frost. Planting too early can cause the rhizomes to rot or simply refuse to sprout.

For most regions in Ontario, the ideal planting window is from late May to mid-June. Use this general timeline as your starting point:

Southern Ontario & the GTA: You can often plant from the third week of May onward.
Central Ontario & Ottawa Valley: Aim for early June to be on the safe side.
Northern Ontario: Wait until mid-June or even late June, depending on your local frost dates.

A great tip is to watch your local weather forecast. A good soil temperature for planting is consistently above 15°C (60°F). If you’re impatient, you can get a head start by planting the rhizomes in pots indoors about 4-6 weeks before your outdoor planting date. Then, you can acclimate and move them outside when it’s warmer.

Choosing and Preparing Your Calla Lily Bulbs

Success starts with healthy bulbs. When you buy them, look for firm, plump rhizomes that feel heavy for their size. Avoid any that are soft, shriveled, or show signs of mold. Bigger bulbs usually produce more and larger flowers in their first year.

Before planting, it’s a good idea to soak your calla lily bulbs in lukewarm water for about an hour. This rehydrates them and gives them a kick-start. Some gardeners also dust them with a fungicide powder to prevent rot, but this is optional if your bulbs look very healthy.

The Perfect Planting Site and Soil

Calla lilies need two main things from their location: plenty of sun and well-draining soil. They perform best in full sun to partial shade. In very hot afternoon sun, a bit of light shade can prevent scorching.

The soil is critical. Ontario gardens often have heavy clay, which holds too much water and will rot calla rhizomes. You must improve drainage. Here’s how to prepare your planting bed:

Choose a sunny spot.
Dig a hole or trench about 10-15 cm (4-6 inches) deep.
Mix the native soil with a generous amount of compost or aged manure. Adding some coarse sand or perlite is excellent for heavy clay soil.
This mix creates a rich, airy, and well-draining environment the roots will love.

Step-by-Step Planting Instructions

Planting calla lily bulbs correctly is simple. Follow these steps for the best results:

Dig: Dig holes 10-15 cm (4-6 inches) deep. Space them about 30-40 cm (12-16 inches) apart so they have room to grow.
Place: Set each rhizome in the hole with the “eyes” or growing points facing upward. If you’re unsure, plant it sideways; the shoot will find its way up.
Cover: Gently backfill the hole with your prepared soil mix and pat it down lightly.
Water: Give them a thorough initial watering to settle the soil around the bulb. After this, water only lightly until you see green shoots appear.

Caring for Your Calla Lilies Through the Season

Once planted, your calla lilies need consistent care to produce those optimal spring and summer blooms.

Watering: Keep the soil consistently moist but never soggy. Once they are actively growing, they appreciate regular water, especially during dry spells. Reduce watering as the flowers fade in late summer.
Fertilizing: Feed your callas every 3-4 weeks during the growing season with a balanced, water-soluble fertilizer. A fertilizer higher in phosphorus can encourage more blooms.
Mulching: Apply a light layer of mulch around the plants. This helps retain soil moisture, keeps roots cool, and supresses weeds. Don’t pile mulch directly on top of the emerging shoots.
Deadheading: Remove spent flowers to encourage the plant to put its energy into possible new blooms rather than seed production.

What to Do With Calla Lilies in Ontario Winters

Calla lily rhizomes are not winter-hardy in Ontario. They will not survive if left in the ground over our freezing winters. You must dig them up each fall. Here is the process:

After the first frost blackens the foliage, cut the stems back to about 5-10 cm (2-4 inches).
Carefully dig up the clumps of rhizomes, trying not to damage them.
Gently brush off excess soil and let them dry in a cool, airy place for a few days.
Store them in a box or paper bag filled with slightly moist peat moss or vermiculite. Place them in a dark, cool (but not freezing) location like a basement, where temperatures stay around 5-10°C (40-50°F).
Check on them occassionally through the winter to ensure they are not shriveling or rotting.

Then, when late spring arrives again, you’ll know exactly when to plant calla lily bulbs in Ontario for another spectacular show.

Troubleshooting Common Problems

Even with great care, you might face a few issues. Here’s how to handle common ones:

No Sprouts / Rotting: Usually caused by planting in cold, wet soil or overwatering before growth starts. Ensure proper timing and drainage.
Yellowing Leaves: Can be a sign of overwatering, poor drainage, or sometimes a need for fertilizer.
Few or No Flowers: Often due to too much shade, overcrowded bulbs that need dividing, or insufficient fertilizer during the growing season.
Pests: Watch for aphids or spider mites. A strong spray of water or insecticidal soap usually takes care of them.

FAQ: Your Calla Lily Questions Answered

Can I plant calla lily bulbs in pots in Ontario?
Absolutely! Container growing is a fantastic option. Use a large pot with drainage holes and quality potting mix. You can bring the pots inside before frost in fall and store the whole pot in a cool place, making overwintering simpler.

How long do calla lilies take to bloom after planting?
Typically, you’ll see blooms about 8-12 weeks after planting the rhizomes in spring. If you started them early indoors, you’ll get flowers sooner in the summer.

Are calla lilies perennials in Ontario?
They are treated as tender perennials. This means they are perennial in their native habitat but, in Ontario’s climate, they must be lifted and stored indoors over winter to return the next year.

Can I leave my calla lilies in the ground over winter?
We do not recommend this. The ground freezes too deeply, and the rhizomes will almost certainly freeze and die. The effort of digging them up is worth it to save your investment.

Why are my calla lily leaves turning brown at the tips?
This is often due to low humidity, inconsistent watering, or a buildup of salts from fertilizer. Try to keep watering consistent and flush the soil occasionally with plain water if you’re growing in containers.

By following this advice on timing, planting, and care, you’ll be well on your way to a garden filled with the elegant, colorful blooms of calla lilies. Their graceful flowers are a sure sign that summer has truly arrived in your Ontario garden.