The allium plant belongs in every garden. These gorgeous spring flower bulbs come in a wide variety of sizes and shapes and are available in hues of violet, purple, pink, yellow, and white. They bloom in various varieties from late spring to summer. Despite not literally smelling like onions, alliums are related to the onion family and are avoided by deer and other animals because of their flavor. Read on to find out when to plant allium bulbs for the best results.
When To Plant Allium Bulbs
Fall is the best time to plant allium bulbs, especially from September through December. Before the ground freezes, this enables the roots to begin to grow, but “The most frequent query is how deep to plant allium bulbs… A decent rule of thumb for determining how deep to plant allium bulbs is to dig the planting hole at least three times the size of the bulb because they can range in size from fairly large to quite little. Alliums, like the majority of flower bulbs, do not appreciate soil that gets too wet, so choose a sunny location “dipping their toes in.
When To Plant Allium Bulbs In Warm Locations
In all of North America’s areas, alliums grow well when planted in gardens, with the exception of the coldest, where they do best when grown in containers that can be protected from winter frost. You can grow alliums as late as December in warm climates.
When Do You Plant Allium Bulbs In Pots?
Alliums should be planted in the fall if you’re growing them in pots. Plant the bulbs in September if you wish to grow alliums inside. Once the shoots begin to grow, keep the pot in a cool, dark location for 8 to 10 weeks. Then, move it to a bright, warm location, where it will soon blossom.
All that’s left to do is choose which allium kinds to grow now that you know when is the ideal time. Browse our allium collection to discover a stunning selection of allium bulbs for any setting.
How late can allium bulbs be planted?
Yes! Alliums are annual plants that grow again year after year. Due of their extreme cold tolerance, they can endure most zones’ winters.
Alliums planted in the spring will still blossom, yes. Although the blossoms won’t be quite as big, they will return the next year in full force.
Allium may only grow as foliar growth, with no blooms, or not at all, if you plant it too deeply. To ensure the best growth and lessen the possibility of shallow bulbs being dug up by animals, try to put allium 4 inches beneath the soil surface.
The spring is not the time to transplant allium bulbs. Wait until the end of the summer when the foliage begins to turn yellow so that the plant will be in a dormant state and not be concentrating on new growth. It will be difficult to locate the bulbs if you wait until the stems totally wilt.
Is January too late to sow allium bulbs?
Remember that late January-planted bulbs could produce flowers with reduced size. On the other side, winter bulb planting can help to safeguard the bulbs. After planting, the ground will freeze more quickly, shielding your bulbs from hungry animals.
What month should alliums be planted?
Most likely, when you think of alliums, you picture those plants with the traditional round, purple flowerheads on long stalks that make borders look amazing in late spring and early summer. Alliums, however, are much more than this.
There are alliums that are white, pink, blue, and yellow. There are some alliums that resemble a fireworks display, and others that resemble knotted dreadlocks.
You can identify that alliums are related to onions, garlic, and leeks by the aroma released when you crush the foliage. This family also includes chives (Allium schoenoprasum), which have delicious leaves that may be sliced and used to salads and dips.
Alliums are a favorite of butterflies and bees, and even the dried flowerheads look lovely in the border or in floral arrangements.
When to plant allium bulbs
The greatest time to plant alliums is in mid- to late-autumn, at the same time as tulips and daffodils that bloom in the spring. Allium bulbs are resilient and can withstand harsh winter weather if they are planted in soil that drains effectively.
Some attractive alliums, like “Allium sphaerocephalon,” flower in the late summer. Most ornamental alliums bloom in the late spring and early summer.
Where to plant alliums
The majority of alliums thrive in full sun and well-drained soil. Tall alliums should be planted in a protected area to prevent the stems from blowing over in high winds. Plant purple-flowered chives (‘Allium schoenoprasum’), which appreciate afternoon shade, or yellow-flowered ‘Allium moly’ in shaded areas.
Tall alliums look great planted in broad swaths or punctuated across a border. Late-summer bloomer Allium sphaerocephalon has gorgeous wine-red flowers that stand out amid the grasses in prairie planting schemes.
Long, slender leaves on ornamental alliums fade back as the flowers emerge. To conceal the waning foliage, place allium bulbs under other low-growing plants.
Planting allium bulbs
- Remove any weeds by turning the dirt over. Dig in leaf mold or compost instead of using manure on heavy soil as this can change the soil’s pH level. Alliums thrive in soil with a pH that is neutral.
- Make a hole that is roughly four times the bulb’s depth.
- Put a bulb in the opening with the roots pointing down.
- Gently compact the earth after filling the hole.
Alliums can also be grown in large pots with soil that is a mixture of grit, John Innes No. 3 compost, and multipurpose compost.
Tips on caring for alliums
- Ground-planted alliums typically don’t require irrigation.
- In the spring, alliums grown in containers will require regular watering. However, avoid letting the compost become soggy as this could lead to the bulbs rotting.
- Crushed eggshells around plants, copper tape around pots, beer traps, or wildlife-friendly slug pellets can all be used to deter slugs and snails from eating new spring leaves.
- When the plants are in bloom, spread a general-purpose fertilizer to aid in the development of the bulbs, assuring healthy flowers the following year.
- Once the leaves have withered back, remove them.
- There is no need to deadhead the flowerheads unless you choose to because they still look excellent after flowering has completed. As long as they remain in place at the border, they may be ignored.
- Put pots in a greenhouse or up against a wall of a house in the winter to shield them from the cold weather.
Growing allium bulbs from offsets
Offsets, which are little bulbs affixed to the main bulb, are produced by many allium bulbs. These can either be planted directly in the ground or split from the main bulb and placed in tiny pots to grow on. Before they have developed enough to produce flowers, it will take a number of years.
Wait until the allium plants are through flowering before using a garden fork to carefully uproot the plants and inspect the bulbs for offsets. Replant the bulbs after removing any offsets.
Best allium bulbs to plant
Alliums come in a wide variety, from large to little, with flowerheads that are rounded or exotic-looking twisted. Here is a selection of the most well-liked alliums.
- One of the most well-known alliums, Allium ‘Purple Sensation’ has the traditional deep purple spherical flowerheads on long, robust stalks. 1 m (3.5 ft) high.
- Large circular purple flowerheads up to 15 cm (6 in) across on robust stems that are 80 cm (3 ft) tall characterize Allium ‘Globemaster’.
- As its name suggests, Allium giganteum is a true giant with dense, spherical purple flowerheads on stems up to 1.8 meters (6 feet) tall.
Allium can be winter-sown.
Whether you’re sowing indoors, directly into the garden, or during the winter in milk jugs, plant your allium seeds at the same time as the rest of your seeds.
What occurs if bulbs are planted too late?
Planting spring flower bulbs at the ideal periods is the best strategy for success. The ideal time to plant bulbs is at least six weeks before the first strong, ground-freezing frost is predicted in your area.
The bulbs need time to take root and become established. On the other hand, early bulb planting can result in fungus or disease issues. Bulbs should be planted, as a general rule, when local average nightly temperatures are between 40 and 50 degrees. When that time comes, the soil’s temperature should be ideal for burying bulbs for the winter. Plant in September or October if you live in a colder northern environment. You might need to plant bulbs in December in warmer climates (or even later).
Don’t wait until spring or the following fall if you forget to plant your bulbs when they should have been. Bulb types differ from seeds. They won’t last in the open for very long. Even if you discover a sack of tulips or daffodils that hasn’t been planted in January or February, plant them nevertheless and take a chance. They should give it a fighting shot in the ground or a cold pot rather than withering away in the garage or a cabinet, whatever the case may be. By design, flower bulbs are survivors. Every year, there are several accounts of bulbs that blossom after being planted in the most unlikely situations.
When can you grow alliums in the UK?
Allium bulbs can still be planted for a fantastic spring show. The photographs demonstrate how Alliums, when planted properly, are low maintenance, return dependably each year, and are unquestionably one of the most fashionable plants for a border.
Alliums prefer a sunny location with well-drained soil, therefore they do not do well in wet, marshy soil, especially during the winter when the bulbs may rot. Alliums can be grown in containers for a patio display or placed in the borders if you don’t have the best growth conditions.
A. Moly, a bright yellow variety, and Chives, which the bees love (see second image), both of which grow to about 30 cm, are relatively little and perfect for the front of the border. The bees and we both enjoy eating chives, which make a great edging plant.
The outstanding Allium Cristophii (shown third image), one of the tallest kinds above 1m, and A. Globemaster are two of the taller types.
It is recommended to plant alliums in the first two weeks of October because they require to be planted in the early autumn. Bulbs may be purchased and planted for a lot less money than plants can this spring. As with all bulbs, it is ideal to plant them in pots that are four times as deep as the bulbs themselves.
Unusual variants include Nectaroscordum siculum, which is technically not an Allium but is sometimes sold as one (6th image).
Although most of us don’t have so much space, alliums look fantastic when planted in large groups, as in photographs 4 and 5, which are from an RHS garden. Alliums can be utilized well as a theme in smaller gardens when planted in groups and recurring perhaps 3/4 times. This will give a border true style.
Staking may be necessary for taller varieties, particularly in exposed places. Allium are simple to grow and put on a fantastic display. They offer good value for money because they come back and bloom year after year with little care.
Allium’s leaves are not appealing, especially after flowering, hence historically, companion plants like Achillea Mollis or Euphorbia have been planted with Allium to hide the leaves.
Alliums can I plant in February?
Some alliums bloom as early as mid-February, making them essential for your spring planting if you’re searching for late winter color. Look at the allium ‘Schubertii,’ which creates a lovely early display with its delicate pink florets. Additionally, as the blooms start to fade in mid- to late-May, you’re left with gorgeously architectural seed heads that continue to lend structure to your borders well into the next growing season.
Vegetables
The month of January is ideal for starting indoor vegetable seeds, including lettuce, peppers, and summer brassicas like cabbage and cauliflower. This year, if you want to grow onions, we advise putting them in a heated propagator. In mild climates, you can plant wide beans in pots; try putting them in a cold frame or a greenhouse.
To add color and a lovely scent to your kitchen, grow your favorite herb seeds on your windowsill. Early in the year, it will give you lovely fresh greens. For a stunning windowsill display, use our Unwins Homegrown Microgreen Growing Kit.
Fruits
Why not attempt to grow rhubarb from seed? In a heated propagator or on a warm windowsill, thinly sow. After seeding, germination will take place roughly 21–40 days later.
Strawberries could even be started in seed trays in a particularly protected area.
Flowers
A hardy annual bedding plant, such sweet peas or antirrhinums, can also be started now (Snapdragons). Start planting perennials like dianthus (carnations), delphiniums, or begonias. Even while it may take them a few years to achieve flowering size, their delayed start is ultimately well worth it.
To start Lobelia under glass or in a propagator for planting in your containers and hanging baskets in the warmer months, January is also a great time.
What depth should allium bulb planting be?
Consider your garden space when choose which alliums to cultivate. Will you be bulk-planting in pots or growing in drifts through the border? as a component of a structured planting plan for prairies? Additionally, it’s crucial to consider the color of your alliums. Although most allium blossoms are purple, some are also blue, white, yellow, and pink in color. Also take into account the size of your allium—both the size of the flowers and the plant’s overall height. Allium flowers can range in size from a few centimeters to over 20 cm (8 in) in diameter, and their eights can also differ greatly.
Planting large, tall alliums singly or in drifts works nicely for varieties like “Purple Rain” and “Globemaster.” Allium christophii and other shorter variants grow well in containers. In prairie planting designs, drumstick alliums like Allium sphaerocephalon look fantastic.
Alliums thrive in a sunny location with excellent soil drainage. They don’t care what kind of soil it is. Plant higher-growing cultivars in the back of a border and lower-growing varieties up front. Although alliums do well in containers, their strappy foliage can become ugly after flowering.
The leaves of alliums develop before the flowers do. As a result, they are frequently better suited to the center of a border where the faded foliage would be hidden and the flowers will put on a display. Plant alliums among attractive grasses and perennials to hide the fading foliage.
Grow alliums in broad drifts through the border or let them naturally grow in your lawn for a striking show.
How to plant alliums
Plant allium bulbs in the fall, at least four times their size deep (at least 15cm deep). It is preferable to plant them deeply rather than superficially.
There is no need to water them in if the soil is damp. Poor soils should be fertilized with a balanced fertilizer in the spring as growth begins to show.