Can Indoor Lilies Be Planted Outside?

Lilies bloom in vibrant hues of pink, orange, yellow, and red and brighten up your home in the dead of winter when there is no color around. But do you know that you can also plant lilies outside?

You can plant potted lilies in your garden if you live in hardiness zones 4-9. They must be planted in full sun to partial shade in well-draining soil amended with compost or rich in organic matter. The best time to plant potted lilies outside is after the last frost date in your region.  

Lilies are hassle-free plants; if planted outside, they will multiply over time and produce multiple flowering stems. The trick is transplanting them at the right time and providing them with the ideal growing conditions. I will explain how you can transplant indoor lilies outside and care for them throughout the year so you can enjoy their spectacular blooms and heady fragrance for years.

How Do You Transplant Lilies?

You should transplant your potted lilies outside after the last frost if you get harsh winters. Remember to harden them off before you plant them out. Also, ensure that you plant your lilies in a sunny spot with well-draining and rich, fertile soil.

The potted flowering lily you bought from a garden center to light up your home in winter was “forced” to bloom. You can plant it in the garden, but it will probably not flower again next summer.

The bulb has exhausted almost all its energy in producing the unseasonal blooms. It has to replenish its lost energy reserves and bulk up before it flowers again, which might be in a couple of years.

Nevertheless, be patient. If you carry out the transplantation process correctly, be assured that your plants will reward you with vibrant blooms after a few years.

Follow the steps listed below to transplant your indoor lilies:

1. Prepare Your Lilies and Harden Them Off

Wait until all danger of frost has passed before transplanting your indoor lilies.

In the meantime, cut back the dead flowers and place the pots in a cool location where the plants can receive indirect light

About a week before you intend to transplant them, keep the potted lilies outside for progressively longer periods during the day.

This exercise will harden the plants. It will make them strong enough to withstand the cool temperatures outside after a lifetime of growing and blooming in the warm cocoon of a greenhouse or living room. 

2. Find and Prepare a Site in Your Yard

Find a sunny location in your yard to plant your lilies. If you live in a region with hot summers, make sure the spot you select is shaded from the scorching rays of the afternoon sun. 

The soil should be rich and fertile. If needed, amend the soil with compost or aged and well-rotted manure.

Ensure the soil is well-draining as well. Otherwise, the roots of the plants will rot.

Here’s how you can check if the soil is draining well:

  1. Dig a hole about 12-18 inches (30-46 cm) deep and roughly 12 inches (30 cm) wide. 
  2. Fill the hole with water.
  3. Let the water drain completely. 
  4. Fill the hole again with water. 
  5. Measure the depth of the water table every hour for two to three hours. 
  6. The water table will drop at least an inch (2.54 cm) every hour in well-draining soil; if not, you must amend the soil.
  7. Dig deeply.
  8. Work in compost or leaf mold to amend the soil and improve drainage. 

3. Plant the Lilies

Remove the lilies from their pots. Be careful so that you don’t damage the roots. This is also the ideal time to divide your plants.

Here’s what you’ll do:

  1. Plant the lilies to the depth that they were in their pots. 
  2. Plant in clumps of 3-5 lilies to create a swathe of color.
  3. Add a slow-release fertilizer that will feed the foliage when the plant sends out new growth in summer. 
  4. Cover the soil with mulch to keep the roots cool. 
  5. Water the lilies thoroughly after planting. 

Asiatic lilies flower in early summer, while the oriental varieties bloom after the Asiatic lilies have faded. Plant multiple types together, so you always have flowers adorning the lily patch from May to October.

Some lilies can grow up to 18 inches (46 cm) tall. That’s why it is a good idea to stake the plants now and prevent them from flopping over later. Trying to drive a stake into the ground long after planting the lilies can damage their roots.

The stems and leaves of the lilies will start to turn brown after you plant them out. This is normal, and the plant will send up new growth in summer. Cut back the dead and withered foliage up to healthy green growth.

4. Take Care of the Plants

Remember that the lilies you plant in spring will usually not flower the following summer. However, the plant will send out new growth. 

The leaves will photosynthesize and feed the bulbs. Cut back these leaves to the ground when they wither and turn yellow in the fall.

You will also need to cover the bulb with a thick layer of mulch to protect it from the frost and retain soil moisture. Now, wait for spring for the bulb to grow new leaves and bloom. 

How Do I Care for Lilies in My Garden?

Take care of the lilies in your garden by ensuring they are always well-watered and protected from intense heat. You should also protect them from pest attacks. Fertilize the plants regularly during the growing period to feed the bulbs so that they bulk up.

Read on as I explain how to care for the lilies in your garden.

1. Water To Maintain Moisture in the Soil

Water the garden regularly to keep the soil moist. You should water copiously if there is less than an inch (2.54 cm) of rainfall in a week.

Do not let the soil dry out in between waterings. You can induce budding and flowering and prolong the blooming period if you keep the plants hydrated. 

2. Mulch the Soil

Like indoor soils, your garden soil also needs to be mulched to retain moisture. Mulching also keeps the roots of the plant cool.

You can use compost, shredded bark, grass clippings, or leaf mold as mulch. Organic mulch breaks down over time, thereby enriching the soil.

3. Fertilize Regularly

Apply a fertilizer with high potassium content every two weeks during the growing period until six weeks after flowering.

A high-potassium fertilizer is used to promote fruiting and flowering in plants. Potassium also helps plants use the water available in the soil more efficiently.

Additionally, potassium enhances the quality and size of flowers and increases the plant’s ability to withstand disease and pest attacks.

4. Prevent Aphid Attacks

Lilies planted outside are vulnerable to aphid attacks. Unfortunately, an aphid infestation can stunt plant growth.

Inspect your plants closely for signs of aphids. An aphid attack starts as white fuzz at the tip of a flower bud or underneath the leaves. Take action as soon as you notice signs of aphids. 

To get rid of the aphids, use insecticidal soap. Alternatively, you can add a tablespoon of dishwashing liquid to a liter of water and hose down the aphids. 

Can I Leave Lily Bulbs in the Ground?

You can leave lily bulbs in the ground if you live in hardiness zones 4-9, where these plants are perennial and come back year after year. However, if you live in a warmer region, you must dig up the bulbs and chill them in a refrigerator before replanting them outside in spring.

The flowers will fade, and the leaves will turn yellow and brown as winter approaches. Therefore, if you want to keep the plants outside, you have to protect the bulbs.

Cut back the dead flowers, but leave the foliage. The green leaves will photosynthesize and produce food for the bulb.

Additionally, you want to cut the leaves back to the ground when they wither and die. It’s also advisable to cover the ground with a thick layer of mulch to protect the bulbs from the frost.

Brush away the mulch when temperatures rise in spring to let the new growth emerge. Applying a layer of mulch will provide food for the plant and bolster it for a fresh growth spurt. 

Key Takeaways

Lilies are fairly low-maintenance plants. Hence, knowing how to transplant indoor lilies outside lets you create a sizeable lily garden over time without spending money to buy more bulbs. 

Keep the following in mind when planting indoor lilies outside:

  • Transplant lilies when all danger of frost has passed.
  • Choose a sunny location with well-drained soil to relocate your plants.   
  • Always keep the soil moist.
  • Fertilize regularly with high amounts of potassium.

Dig up and preserve the bulbs in a refrigerator if you live in a warm region.

Alexander Picot

Alexander Picot is the founder of TheGrowingLeaf.com and its lead content writer. He created the website in 2022 as a resource for horticulture lovers and beginners alike, compiling all the gardening tips he discovered over the years. Alex has a passion for caring for plants, turning backyards into feel-good places, and sharing his knowledge with the rest of the world.

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