How to Plant Calla Lily Bulbs

Learn how to plant calla lily bulbs for stunning garden blooms with our step-by-step guide (including photos of which side is up!)

Shopping at Costco is not for the faint of heart (or light of wallet). Usually I can avoid the siren song of a year's supply of pickles and just get what I need. But every spring, they get me with their huge display of plant bulbs!

This year, I picked up quite a few of these "bulbs in a bag," including this assortment of calla lilies. Who could pass up six new gorgeous plants for less than $2 each!?!

These stunning flowers, known for their trumpet-shaped blooms and vibrant colors, can make a striking statement in any garden. However, to ensure healthy growth and long-lasting beauty, it's essential to plant calla lily bulbs correctly.

In this article, I will guide you through the entire process of planting calla lily bulbs step by step, so you can enjoy these show-stopping flowers in your own garden. Let's get growing!

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Planting Calla Lily Bulbs at a Glance

Best Planting Time	Plant 2-3 weeks after the last frost date.
Location & Sunlight	Full sun to partial shade. 6 hours of direct sunlight is ideal, with afternoon shade in hotter climates.
Soil Requirements	Well-draining, slightly acidic to neutral (pH 6.0-7.0).
Bulb Storage	Store in a cool, dark, dry place in a breathable container if not planting immediately.
Correct Bulb Orientation	Flat side down, rounded side with bumps (eyes/shoots) up. If unsure, plant on its side.
Planting Depth & Spacing	Plant bulbs 4 inches deep, spaced at least 6 inches apart.
Fertilization (Optional)	Add a small handful of Bulb-Tone or similar fertilizer in each planting hole for nutrient boost.
Planting in Pots	Use pots 10-12 inches in diameter with drainage holes filled with well-draining potting mix. Plant bulbs 4 inches deep, 6 inches apart.
Post-Planting Care	Water regularly to keep soil moist but not soggy. Monitor for pests/diseases.
Winter Care in Cold Zones	In zones below 8, dig up bulbs after foliage dies back. Dry for a few days, remove soil, and store in a cool, dark, dry place.

When to Plant Calla Lily Bulbs

Timing is crucial when planting calla lily bulbs to ensure they have the best chance of thriving in your garden. Here's what you need to know about when to plant them.

After the risk of frost has passed

Calla lilies are sensitive to cold temperatures, so it's essential to plant the bulbs after the risk of frost has passed in your area. Frost can damage the bulbs and prevent them from growing or flowering properly. To find out when the last frost date typically occurs in your region, search online for the frost date of your zip code.

Timing in different zones

Calla lilies are perennial in USDA hardiness zones 8-10, meaning they can survive winters in these zones and come back year after year. If you live in a colder zone, you'll need to dig them up in the fall and store them for the winter to replant them the following spring.

In general, the best time to plant calla lily bulbs is in the spring, about 2-3 weeks after the last frost date. By planting at this time, you'll give the bulbs ample time to establish themselves before the hot summer months arrive, allowing them to produce their stunning blooms.

Choosing the Right Location

Selecting the perfect spot in your garden for your calla lilies is crucial for their growth and overall health. Consider the following factors when choosing a location.

Sun requirements

Calla lilies thrive in full sun but can also tolerate partial shade, especially in hotter climates. Ideally, you should aim to provide your plants with at least 6 hours of direct sunlight daily.

If you live in an area with scorching summers, a spot with dappled shade during the hottest part of the day can help protect the plants from excessive heat and prevent the blooms from fading too quickly.

While our summers can be pretty mild here in Seattle, I'm planting these bulbs in a spot in my garden that gets dappled shade from our Twisty Baby black locust tree. They'll fit nicely in that blank spot between the daffodils and tulips on the left and the honeysuckle bush on the left.

Soil and drainage requirements

Calla lilies prefer well-draining soil, which allows excess water to flow away from the bulbs and prevents rot. Our soil is quite sandy, which is great in a place like Seattle that gets a lot of rain!

In addition, these plants prefer a slightly acidic to neutral pH level (between 6.0 and 7.0). You can test your soil's pH using a simple soil test kit available at most garden centers. If your soil is too alkaline, you can amend it with elemental sulfur to lower the pH.

Preparing Calla Lily Bulbs for Planting

Before you start planting, you should check your calla lily bulbs to make sure they're healthy. You don't need to soak the bulbs or do any special preparation, but you don't want any unwanted surprises!

Inspecting bulbs for health

Examine your bulbs carefully before planting. Healthy bulbs should feel firm to the touch and be free of any visible mold, rot, or damage. Discard any bulbs that appear unhealthy or damaged, as they may not grow well or could introduce disease to your garden.

Storing bulbs

If it's too cold to plant your bulbs immediately, store them in a cool, dark, and dry place, such as a basement or garage, until planting time. Keep them in a breathable container, like a paper bag or cardboard box, to prevent moisture buildup, which can lead to rot.

Determining the correct side to face up

Calla lily bulbs (which are actually rhizomes) have a flat side and a rounded side, and it can be challenging to determine which side should face up when planting.

The flat, smooth side is where the roots will grow, while the rounded side with all the bumps is where the shoot will emerge. If you're unsure, plant the bulb on its side, and the shoots will naturally grow upward.

One of the bulbs in my package was already starting to sprout, making it easy to see which way is up. You can see the green shoots coming out of the eyes on the top of the bulb. Each of those bumps on the surface will hopefully become a bloom!

Planting Calla Lily Bulbs Outside

Now that you've chosen the perfect location and the weather has warmed up a bit, it's time to plant your calla lily bulbs in the ground. Here's how!

Depth and spacing requirements

Dig your holes at a depth of 4 inches, and space them at least 6 inches apart. This will give each plant enough room to grow and spread without overcrowding. I like to use a 3" auger attached to my cordless drill to make perfect holes without bending over!

Add fertilizer (optional)

To give my plants a boost, I like to add a small handful of Bulb-Tone into each hole. As the roots develop, they'll have the nutrients they need to produce strong stems and beautiful flowers right away!

Place the calla lily bulbs face up

Place the bulb in the hole with the flat side facing down and the rounded side with the bumps facing up. Fill the hole with soil, covering the bulb completely and gently firming the soil around it to eliminate air pockets.

If you have a mix of varieties like the ones I bought, make sure to place the taller ones behind the shorter ones, preferably to the north. The pink Garnet Glow grow up to 20", so they went behind the purple Grape Velvet that only get 18" tall. This ensures that they won't block the sunlight, and you'll be able to see them all!

Planting Calla Lily Bulbs in Pots

If you prefer to grow your calla lilies in containers, or if you have limited garden space, here's how to plant your bulbs in pots:

Choosing the right pot and soil

Select a pot or grow bag that is at least 10-12 inches in diameter and has drainage holes at the bottom to prevent waterlogging. Use a well-draining potting mix, preferably one that is slightly acidic to neutral (pH 6.0-7.0). You can also create your own mix by combining equal parts of peat moss, perlite, and compost.

Planting depth and spacing in containers

Plant your bulbs at a depth of 4 inches in the pot, ensuring that there's at least 2 inches of soil below the bulb. Space the bulbs at least 6 inches apart to give them enough room to grow.

Caring for potted calla lilies

Place your potted plant in a location that receives at least 6 hours of direct sunlight daily. Water the soil regularly, keeping it consistently moist but not soggy. Overwatering can lead to rot, while underwatering can cause the plants to wilt.

Feed your calla lilies with a balanced, slow-release fertilizer according to the package instructions. Monitor your plants for any signs of pests or diseases and treat them promptly to keep them healthy and beautiful.

Caring for calla lilies in colder zones

If you live in a colder climate (zones below 8), you'll need to dig up your calla lily bulbs in the fall to protect them from freezing temperatures. After the foliage has died back, carefully lift the bulbs out of the ground with a garden fork, leaving as much soil around the roots as possible.

Allow the bulbs to dry in a well-ventilated area for a few days, then shake off the soil and store them in a cool, dark, and dry place until it's time to replant them the following spring.

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I can't wait to see my garden bed full of calla lilies in a few months! I'll be sure to add photos once they're in bloom!