Alliums are well-known flowering bulbous plants that include garlic, onions, leeks, chives, and hundreds of other species. In the garden, their round flowerheads on long, thin stems make magical, sculptural effects. Because they grow in so many different ways, it’s no surprise that allium bulbs have become garden staples.
If you’re new to alliums, you may be wondering – can you plant allium bulbs in the spring? While most sources recommend fall planting, planting allium bulbs in spring is often successful too. Here’s what you need to know about the best planting time for allium bulbs and how to grow these beauties in spring.
Why Fall is the Recommended Planting Time
Flower bulbs like tulips, daffodils, crocuses, and alliums are usually planted in the fall. So they have the time to get cold enough to start root growth. When bulbs are kept at temperatures between 35°F and 48°F for at least 8 to 12 weeks, biochemical changes happen that encourage root growth. Root growth is very important because bulbs use roots to take in water and nutrients that help them grow. You won’t get many or any flowers if the roots aren’t strong.
Another reason to plant bulbs in the fall is to give them enough time to grow leaves. Leaves give bulbs the food they need for next year’s flowers. If there isn’t enough foliage, the flowers will be smaller or not come at all the next year. Bulbs that were planted in the fall have a full winter and spring to grow plenty of leaves before they bloom in the summer.
Finally, fall planting coincides with the natural growth cycle of bulbs. It fits their needs for chilling, rooting, foliage growth and blooming at the right times. Spring planting interrupts this cycle so flowers may be reduced or bloom may be delayed until the next year while bulbs adjust.
Spring Planting Can Work Well Too
Even though fall is ideal you can successfully plant allium bulbs in spring. The key is getting them in the ground as early as possible while soil is still cool. This gives bulbs a bit of chilling time to start the rooting process before warm weather arrives.
Aim to plant large bulbs like alliums about 4-6 weeks before your projected last spring frost. Smaller bulbs like crocuses, grape hyacinths and squills can go in 2-3 weeks before the frost date Prepare the soil well by mixing in compost or other organic matter to improve drainage
Plant bulbs at the recommended depth according to package directions. Space them appropriately for good air circulation. After you plant, give the area a lot of water and cover it with two to three inches of organic mulch. The mulch helps keep the soil cooler for a little longer and keeps water in, which helps bulbs grow roots.
Expect Some Differences With Spring Planting
When planted in spring rather than fall, bulbs may bloom at slightly different times, or flower size or quantity may be reduced. But with proper care, spring-planted bulbs can still thrive and put on a gorgeous display. It just takes patience and realistic expectations.
For example, tulips and daffodils may not bloom much if at all the first spring after planting. Often these bulbs need a full year to settle in before flowering. Flowering in year two and beyond should improve as bulbs become established.
Some alliums and other bulbs will still bloom decently the first year from spring planting. Flower size or number may be smaller than normal. But once settled in, bulbs should perform well in following years.
Tips for Successful Spring Bulb Planting
Here are some useful tips to help your spring-planted bulbs do their best:
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Plant as early in spring as possible when soil is cool but workable.
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Prepare soil well by mixing in compost or aged manure.
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Choose a spot with good drainage – avoid soggy areas.
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Plant at the proper depth according to package directions.
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Space bulbs appropriately so air can circulate.
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Water newly planted bulbs well then mulch to conserve moisture.
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Fertilize lightly with bulb fertilizer or bone meal.
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Allow foliage to die back naturally after blooming.
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Leave cleanup of bulb beds until late fall to allow food production.
Enjoy the Versatility of Alliums
With their pleasing rounded shapes and vivid colors, alliums provide fabulous texture and vertical interest to gardens. They pair elegantly with broad-leaved plants like hostas. Try combining different allium varieties for a continuous bloom sequence. Foliage remains attractive long after flowers fade.
Though fall planting is best, with proper care allium bulbs can thrive when planted in spring too. The key is early planting while soil is still cool to allow some root growth before warm weather. So don’t be afraid to add allium bulbs to your spring garden shopping list. Just focus on choosing the right planting location and giving bulbs a little extra attention. In no time at all, you’ll be rewarded with a breathtaking allium display.
Tips For Planting Allium Bulbs
- Allium plants can grow in USDA Hardiness Zones 3 through 8.
- Allium bulbs that bloom in the spring should be planted in the fall, so they have at least 12 weeks of cold weather before spring.
- If you want flowers, plant your plants in a sunny spot.
- A spot that gets full sun is best for an allium patch.
- Choose a fertile soil type with good drainage.
- Bulb rot can happen if the bulbs sit in soil that doesn’t drain well.
- This same concept applies to moisture provision.
- Allium bulbs can also rot if they get too much water or stay wet for too long.
- When you plant, water the soil, and then when it gets dry in the spring, water as needed.
- It is known that alliums can handle drought, but they will droop if the soil gets too dry. If you see plants drooping, make sure to water them.
- Other than that, let nature take care of the plants’ water needs.
These are some considerations for planting allium bulbs:
The Benefits Of Allium
There are many good things about alliums, like their pretty flowers for the garden, their ability to keep pests away, and their use in cooking.
Some alliums are very tall and stately, and make quite a visual impact, even when only a few specimens are planted. Others may be smaller, and yet still be very beautiful, especially when grown together in clumps.
Some alliums are grown for consumption, and are used regularly in culinary applications. Not all are edible however, such as the ornamental alliums, so know your alliums before consuming.
Alliums produce a chemical compound called sulphate, which contributes to the typical onion or garlic flavor of most of these plants.
The allium is considered to be a natural pest repellant due to it’s sulfur-like and oniony smell. The plants will deter aphids, grubs, nematodes, and even Japanese beetles.
These plants therefore make great companion plants for roses, as well as other plants in the garden.
For the sake of this post we will be discussing ornamental alliums, which are grown for the flower garden.
When they are in bloom, allium flowers look like fireworks in the garden. The spherical blooms consist of many tiny star shaped flowers, which extend out to form pom pom shaped clusters.
The many tiny individual flowers on individual stalks lend to a sparkling and dazzling display.
Most allium plants have purple flowers, although there are different varieties with different shades of purple. Some alliums have white blooms as well.
The flowers are perched atop strong stems, and generally do not require staking.
Ornamental alliums come in a variety of different sizes, from the tall and stately giant allium, to smaller, dainty, front of the border varieties.
Allium flowers are eye catching when in bloom, however they are also visually appealing when they are spent. The globe shaped seed pods which form after blooming are also intricate, and interesting in the garden.
Ornamental alliums make wonderful cut flowers, and look elegant in flower arrangements.
How to plant allium bulbs for beginners
FAQ
What happens if you plant allium in the spring?
Some allium varieties are also planted in spring, and these varieties do not require a winter chill before planting. Consider growing alliums in your garden bed. They bloom early and are very interesting. They look great in cottage gardens with tulips and daffodils.
What month is best to plant allium?
It’s easy to grow allium flower bulbs because they can handle most types of soil and are hardy down to zone 4. They should be planted in fall between September and November, before the soil freezes. You will rarely have to worry about watering them as they actually prefer dry conditions.
What’s the latest you can plant allium bulbs?
For the best results, plant allium bulbs in the fall. If the bulbs are still healthy in December, you can plant them later that month. Do not plant bulbs if they are mouldy, soft or rotten as this could affect the other bulbs in the area.