FAQs: How To Grow Alliums?

Alliums, the family of garlic and onions, bring structure, color, and elegance to every garden. These ornamental bulbs reward you with tall, globe-shaped blooms that return year after year. Whether you’re a new gardener or an experienced one, growing high-quality Allium bulbs is easy with the right care. On this page, you will find frequently asked questions about how to plant, grow, and enjoy Alliums, making your garden truly unforgettable.

What Are Ornamental Alliums?
Alliums are ornamental flowering bulbs (ornamental onions), known for their tall stems and striking globe-shaped blooms. They add structure, color, and elegance to gardens from late spring to early summer. Available in many sizes and shades, these hardy, low-maintenance plants thrive in sunny spots and well-drained soil, returning year after year with minimal care.

What Do Allium Bulbs Look Like?
Allium bulbs are the underground storage organs of the Allium plant. They are round or slightly oval with a papery outer coating, similar to onion bulbs but usually smaller. They range in size depending on the variety. Some are as small as a marble, while others are as large as a golf ball. The bulb’s firm texture and layered structure store the nutrients needed for growth.

What Are The Different Colors Of Allium Flowers?
Allium flowers are most commonly found in shades of blue, violet, and purple, but they also come in red, pink, yellow, and white. Some varieties, like “Star of Persia”, produce enormous blooms up to 12 inches wide, while Allium “Gladiator” and Allium “Giganteum” are known for their tall stems and large, impressive flower heads.

What Month Do Alliums Flower?
Alliums typically flower from late spring to early summer, depending on the variety and your local climate. Bulbs planted in October usually produce the longest and most consistent flowering period.

Where Do Alliums Grow Best?
Alliums grow best in sunny locations with well-drained soil. Taller varieties do well when planted toward the back of borders, where surrounding plants can help support their height. Whether in garden beds or borders, Alliums flourish in open, bright areas that allow their striking blooms to stand tall and make a lasting impression.

Do Alliums Prefer Sun Or Shade?
Alliums prefer full sun, where they can receive at least six hours of direct light each day. While most varieties can tolerate a bit of partial shade, they thrive best in bright, open spots.

What Should You Not Plant Near Alliums?
You should avoid planting Alliums near shade-loving plants like Ferns, Hostas, and Epimediums, as they prefer very different growing conditions. Alliums thrive in full sun and well-drained soil, which doesn’t suit these plants. In the vegetable garden, don’t plant Alliums near beans or peas, as they can hinder each other’s growth.

What Looks Good Planted With Allium?
Alliums pair beautifully with many garden favorites. They look especially striking when planted alongside Irises and Peonies, which complement their tall, sculptural blooms. For a softer, romantic look, combine Alliums with white-flowering plants or with Nepeta, which blooms at the same time.

What Month Is Best To Plant Allium Bulbs?
The best month to plant Allium bulbs is October, when the soil is 60° Fahrenheit or colder, but not frozen. Alliums are spring-flowering bulbs, so planting them in early to mid-fall gives them time to establish strong roots before winter. You can plant them at the same time as Daffodils, Tulips, and Hyacinths. Read more in our guide “When To Plant Allium Bulbs?”.

Can I Plant Alliums In November?
You can plant Allium bulbs in November. In fact, October to November is generally the ideal planting window for most climates. If you live in a warmer region, you can even plant them in December or early January.

How Late Can You Plant Allium Bulbs?
Allium bulbs are best planted in October, but you can plant them later if necessary. Planting later in the season may lead to slightly shorter bloom times, but your display will still be beautiful as long as the bulbs have time to establish roots before the ground freezes.

What Happens When You Plant Allium Bulbs Too Late?
When Allium bulbs are planted too late, they may not have enough time to develop strong roots before winter. While you can plant healthy Allium bulbs as late as December, late planting often results in smaller plants and fewer blooms.

Do You Need To Soak Allium Bulbs?
You should not soak Allium bulbs before planting. Soaking can cause the bulbs to absorb too much moisture and rot before they have a chance to grow. Instead, plant them directly into well-drained soil and water thoroughly after planting.

How To Plant Allium Bulbs In The Fall?
The best way to grow Allium bulbs in the fall is by following the steps below:

1. Choose a sunny location with well-drained soil and plant before the ground freezes.
   
2. Dig holes about 6 inches deep for large bulbs and 4 inches deep for smaller ones, leaving 3 inches between each bulb.
   
3. Place each bulb with the pointed end facing up, then cover with soil and water well. In containers, you can position the bulbs closer together.

How Deep Should Allium Be Planted?
Allium bulbs should be planted at a depth of about 4 times the diameter of the bulb. This helps protect them from frost and ensures strong, upright growth. Dig a hole around 6 inches deep for large Allium bulbs and around 4 inches for smaller Allium bulbs.

How Many Allium Bulbs Should I Plant?
For a stunning display, plant Allium bulbs close together in small groups or rows of about ten bulbs. Spacing them 3–4 inches apart helps create full, eye-catching clusters when they bloom. Planting in groups rather than single bulbs gives your garden a more natural and impressive look.

How Many Alliums Do You Get From One Bulb?
From one Allium bulb, you usually get a single sturdy stem topped with one large, round flower head.

Will Dried-Out Allium Bulbs Grow?
Dried-out Allium bulbs can still grow—if they’re firm and not moldy. If the bulbs feel solid and plump, they are still viable and likely to sprout once planted. However, bulbs that are soft, shriveled, or cracked should be discarded, as they won’t recover.

Can Alliums Be Grown In Pots And Containers?
Alliums can be grown in pots and containers. Choose a deep container that allows you to plant each bulb at a depth of about 4 times its diameter. Good drainage is also essential. So use a pot with holes and a well-drained soil mix to prevent bulbs from sitting in water and rotting.

How Long Does Allium Take To Grow?
Alliums typically take around 12 to 14 weeks to grow after planting. Once planted in the fall, the bulbs establish roots before winter and then remain dormant until spring. As temperatures rise, the shoots emerge, leading to tall stems and globe-shaped blooms by late spring or early summer.

How To Care For Allium Plants?
Alliums are easy to care for and thrive with minimal attention. Since they’re naturally drought-tolerant, they don’t need frequent watering. Plant them in a sunny spot, as Alliums require plenty of light to grow strong and bloom beautifully. Feeding isn’t usually necessary, but if your soil is poor, apply a balanced fertilizer in spring to support healthy growth and vibrant flowers.

What Is Eating My Allium?
If your Allium is being eaten, the most likely culprits are Allium leaf miners, onion maggots, or slugs. Allium leaf miner larvae burrow into leaves and bulbs, causing rot and distortion. Onion maggots feed on bulbs underground, while slugs often chew on leaves and blooms, especially at night.

What Do You Do With Alliums After They Bloom?
After Alliums finish blooming, let the leaves die back naturally, so the bulbs can store energy for the next season. Once the foliage has completely withered, you can cut it down to ground level. Leave the bulbs in the soil over winter—they’ll stay dormant until spring. Every 3 to 4 years, divide and replant the bulbs to maintain healthy growth and create new clusters throughout your garden.

Should You Deadhead Alliums?
It’s best to let the foliage die back naturally before removing anything. The leaves continue to photosynthesize after flowering, helping the bulb store energy for next year’s growth. However, if the foliage turns brown while the plant is still in bloom, it’s safe to trim away the dead leaves.

Do Alliums Come Back Every Year?
Alliums come back every year. They are hardy perennials that, once planted in a well-suited environment, will bloom beautifully each spring and return for many seasons. This makes them a lasting and reliable addition to any garden.

How Many Years Do Alliums Last?
Alliums are long-lasting perennials that return and bloom year after year. To keep them healthy and encourage consistent flowering, it’s best to divide the bulbs every 3 to 4 years.

Why Didn't My Alliums Bloom?
If your Alliums didn’t bloom, several common issues might be the cause. The most frequent reasons include planting the bulbs too shallow, planting them at the wrong time of year, or placing them in a spot that doesn’t get enough sunlight. Another possibility is poorly drained soil, which can cause bulbs to rot before they have the chance to bloom.

Why Have My Alliums Died?
If your Alliums have died, it could be due to Allium white rot, a common fungal disease that attacks the bulbs and roots, causing the plant to wither prematurely. However, it’s also possible that your Alliums are simply dying back naturally after their blooming season.

Why Are My Allium Leaves Drooping?
If your Allium leaves are drooping, it’s most likely due to watering issues. Overwatering can cause the bulbs to sit in soggy soil, leading to rot, while underwatering can dry them out. Although Alliums tolerate drought, they still need occasional watering during long dry spells.

Why Have My Alliums Come Up Blind?
If your Alliums have come up blind—producing leaves but no flowers—the most common cause is removing the foliage too early in the previous season. The leaves require time to die back naturally, so the bulbs can store enough energy for next year’s blooms. Other possible reasons include planting the bulbs too shallow or damage from severe winter frost.

How To Propagate Allium?
To propagate Alliums, simply divide the bulbs every 3 to 4 years. After the foliage has died back, carefully lift the clump from the soil and separate the smaller offset bulbs from the main one. Replant these offsets. With time, they’ll establish themselves and grow into mature plants, ensuring a continuous, healthy display year after year.

Do Allium Bulbs Multiply?
Allium bulbs do multiply over time. After planting, they usually germinate within about 12 weeks and begin to establish themselves. When grown in the right conditions, they will naturally multiply and form larger clumps over the course of 3 or more years.

How To Store Allium Bulbs After Flowering?
To store Allium bulbs after flowering, let the foliage die back naturally, then lift the bulbs from the soil and allow them to dry for a few days. Once dry, place them on paper in a cardboard box or paper bag and store them in a cool, dark, and dry location such as a garage or basement. Avoid storing bulbs in plastic or a freezer, as trapped moisture can cause them to dry out or become moldy.

Are Alliums Toxic To Pets?
Yes, Alliums are toxic to cats and dogs. They contain compounds that can cause serious health issues if eaten, even in small amounts. This includes all parts of the plant—bulbs, leaves, and flowers. If you have pets that like to dig or chew plants, it’s best to plant Alliums in areas they can’t reach to keep your garden beautiful and your pets safe.

Are Alliums Deer Resistant?
Yes, Alliums are deer-resistant. Their slightly garlicky scent and taste naturally deter deer, rabbits, squirrels, and other rodents from eating them. This makes Alliums an excellent choice for gardens in areas where wildlife often causes damage.

Where To Buy Allium Bulbs?
You can buy high-quality Allium bulbs from DutchGrown, a trusted Dutch supplier known for top-sized bulbs that produce tall stems and striking globe-shaped blooms. We offer a wide selection of Allium varieties in different heights, colors, and sizes—perfect for adding structure and elegance to your garden. All bulbs are shipped throughout the US.