When to Plant Alliums – Planting Guide 2022

Save for later!

when to plant alliums

There are many spring bulbs that you can plant but if you want a real showstopper, consider the allium. Part of the onion family, these bold globes of flowers will make your spring garden a more vibrant affair.

When to plant alliums: Allium bulbs should be planted in the fall. This can be between late September and early November. Try to plant before the first frost; however, they are quite hardy so if you get them in the ground a bit later, they should be ok. It’s much easier to plant allium bulbs when you can work the soil, so make sure it isn’t frozen or too cold. After you plant the bulbs, they will stay in their dormant state. Then, when the weather warms up in the spring, they will begin to sprout. Alliums bloom a bit later in spring, after tulips and daffodils. You can expect their globe-like blooms to be out in early to late May, depending on your location and the variety. After blooming, you can tidy up the flowers but leave the foliage so that the bulbs can receive enough nutrients to flower the next year. There’s no need to dig up the bulbs as they will stay in the ground and bloom every subsequent spring.

Planting Alliums in Different Climates

Tropical Climate

Allium bulbs need to have a period of dormancy so that they can store their energy. Furthermore, they need a climate that is not too damp as this can lead to root rot. As such, a tropical climate is not ideal for alliums.

Dry Climate

While alliums do need some water, they don’t need a lot of it. In fact, except for watering the bulbs after planting, you don’t really need to water much to keep these plants alive.

You can definitely plant alliums in a dry climate. However, if it is very dry, monitor the plants and amend your hand watering schedule as needed.  

Temperate Climate

Alliums will do very well in a temperate climate. It will provide the cooler winter temperatures needed for the bulbs. However, a temperate climate may have a lot of rainfall. It is best to check the soil and make sure it isn’t compacted so as to avoid the bulbs from rotting.

Continental Climate

Alliums are especially great for a continental climate. They can withstand very cold temperatures, which is key for these areas. Just keep in mind that your alliums might bloom a bit later than in other areas as they will need to wait for the soil to warm up.

Polar Climate

Alliums do well in colder areas and you might be able to try them in a polar climate. They do need full sun conditions, so it might be hard to grow them.

Choosing Alliums Bulbs

choosing allium bulbs

Purple Sensation

One of the more popular varieties of alliums, these large globes of tiny flowers have a deep purple shade to them. The blooms are long-lasting and will stay in your garden for up to two weeks.

Mount Everest

Named after the fact they look like a snow-capped mountain, this globe of white flowers can make a great contrast with other, more colorful varieties of alliums. The globes are 6 inches wide and will bloom later in spring and even early summer.

Drumstick Allium

The globes of this variety are slightly tapered and have a very busy look to them. They begin as flowers that are lime green in color and then transform into a deep purple.

Blue Allium

Smaller in size than other varieties, these globes measure about 2 inches wide. The bright blue color is incredibly vibrant and the stalks can tower up to 2 feet tall.

How to Plant Alliums Bulbs

Timing

Allum flowers grow in mid-spring. Depending on where you live, this will be between late April and early May.

In order for the flowers to bloom during this time, it is best to plant in the fall. You will want to get your allium bulbs into the ground before the first frost date.

Late September to early November will give you a wide window and you can plan according to your climate. While the bulbs are quite hardy, it is much easier to dig your garden when it isn’t hard or frozen, so make sure the temperatures are mild enough to allow for the planting process.

Soil conditions

Alliums are an incredibly versatile plant. They don’t have any major soil preferences and will do well in soil that is slightly acidic.

You should make sure the soil isn’t too compact when planting, so you may want to dig around a bit before you start to plant the bulbs.

You can also add some compost to your soil in order to add nutrients. However, you don’t have to go overboard with these plants.

The one caveat with soil is that alliums don’t like to be in standing water. Make sure the soil can drain well so that the roots don’t become waterlogged. If there isn’t enough drainage, root rot can set in.

Location

Alliums like sunny spots, so are sure to plant them in areas that get full sun. Be sure to think about what the location will look like in the spring.

So often when you plant bulbs in the fall, trees will be bare and you might think you have full sun. Then, in the spring when trees grow their leaves again, it turns out the area is actually pretty shady.

You can plant alliums in most areas around North America. They are fine with cold temperatures in the winter and can withstand up to plant hardiness zone 4.

Planting

When planting your allium bulbs, try to dig holes that are about 3 inches deep. While the flowers of alliums are usually just one stalk, their foliage around the base of the plant can be quite wide.

Try to space your alliums about 6 to 8 inches apart. They can be a bit closer to other perennial plants if you know they aren’t early spring growers.

Alliums can be quite tall, so they are great if you want to add depth to your garden. You can spread them around as you want.

You can plant alliums in your garden or in containers. Because they are later spring bulbs, you can pair them with earlier bulbs, such as tulips so that you have flowers for the entire spring.

How to Water Alliums

Overall, alliums are fairly drought tolerant. They are an excellent addition to your garden if you want plants that are low maintenance.

After you plant your bulbs in the fall, you can give them a bit of watering. However, as fall is usually a pretty moist season, if there is rain in the forecast, you can forgo this step.

During winter, you will not need to water your bulbs. They will be underground and will receive enough water through rain and snowmelt.

During the spring, you may want to water your plants if you live in a dry area. However, alliums prefer dryer weather, so you don’t really have to worry about the process.

Finally, in the summer, you can keep your allium bulbs in the ground. As you will most likely plant other flowers around these bulbs, you will be inadvertently watering them as you tend to your other plants.

How to Grow Alliums

how to grow allium bulbs

Leave the foliage

Alliums are bulb flowers and you can leave the bulbs in the ground all year long. They will become dormant in the winter and then sprout up again in the fall.

After your allium flower is done blooming, you can cut the top off to clean up your garden. However, it’s important to leave the stalk and the rest of the foliage.

This green part of the plant will provide important nutrients that are then stored in the bulb for new growth the following year. If you cut back this greenery too early, you won’t have strong enough flowers the next spring.

How long do alliums take to grow?

After planting allium bulbs in the fall, they will bloom next spring. Then, if you leave them in the garden, they will continue to bloom each subsequent spring.

Alliums are a later flowering bulb plant. They don’t flower until after tulips and daffodils so they are a nice transition to have while you’re waiting for other perennial flowers to start to grow in later spring.

Are alliums deer resistant?

Anyone who lives in a rural area will know the heartbreak of planting flowers only for roaming deer to make a quick meal out of them. It’s good to know, then, that alliums are indeed deer resistant.

Because they are part of the onion family, they have a subtle smell that is off-putting to deer. You can rest easy knowing your alliums won’t be a deer’s next snack.

Conclusion

Allium bulbs are a great way to add some color and texture to your garden. Flowering in mid-spring, these bulbs only need to be planted once and they will flower every spring afterward.

Related Articles:

Save for later!

Leave a Comment