What is Allium and How to Take Care of It?

Did you know that green onions you buy from the store belong to the big family of Alliums? A lot of exponents of this specie may be the right choice for your garden! Whether you are a professional gardener or only a beginner, this flower might be the perfect solution for your ground. Its geometrical shapes and majestic flowers give you the possibility to easily design your yard while guaranteeing easy care.

This flower is often used in bouquets to wish luck, as it symbolizes good fortune unity and prosperity. So if someone is launching a business or doing something significant, it may be a good idea to take into consideration the Allium flower as a gift! 

What is Allium

Brief history

Have you ever wondered why the name of this plant is not just onion? There are two main theories about the etymology of the word ‘Allium’: one tells it comes from the Latin word Allium that means Garlic, the other one says that it derives from the Celtic word All that means to burn. Generally speaking, this plant has an ancient history, with significant chance populations of Indochina were already cultivating it thousands of years ago. This kind of plant firstly appears in Linnaeus’s book Species Plantarum (1753), where the author, for the first time, groups all the varieties of the onion, edible and ornamental.


Allium flower has different colors like purple, blue, white, pink and yellow. The shape of the flower is spherical, and the size may vary from a couple of centimeters to something about 20 centimeters. The height of this plant may reach in some varieties 150 centimeters! Leaves are sharp and straight, remembering the shape of the edible one you can find at your nearest grocery shop. Allium has a typical onion smell and taste due to the content of essential oils. Its root is a slightly flattened bulb, covered with scales of brown, white or purple color. Allium is considered a summer flower, and its blooming period is about 40-50 days.


Today we know about 1000 types of Allium, but we are still uncertain due to the daily discoveries scientists make. We know for sure that most of them are growing almost everywhere globally but struggling in the Tropics. Edible varieties include onion (Allium cepa), Garlic (A. sativum), chive (A. schoenoprasum), and leek (A. porrum) while the rest usually is used as decorative. If you are wondering which variety to plant in your garden, we can recommend some of our personal choices.

Pink Lily Leek:

This variety of Allium has eye-striking bright pink petals, and its height is not one of the tallest, so we recommend planting it in bulk.

Name: Allium oreophilum

Blooming: Late spring

Flower head: up to 9 cm.

Height: 45-50 cm.

Globemaster Allium:

It’s a very widespread specie of those onions, and it’s a good choice for bouquets as the cut flower lasts longer than his brothers.

Name: Allium Globemaster

Blooming: Late spring

Flower head: up to 25 cm.

Height: 115-120 cm.

Drumstick Allium:

As the name suggests, it has a particular shape similar to drumsticks. We recommend you grow it in large bushes to make an accent on that strange but beautiful variety.

Name: Allium sphaerocephalon

Blooming: Early summer

Flower head: up to 6 cm.

Height: 80-90 cm.

Star of Persia:

This one is famous for its large diameter of the bush, reaching up to 50 cm. The petals are thin pink and elegant and may reach a quantity of 100 per single root. 

Name: Allium cristophii

Blooming: Late spring

Flower head: up to 30 cm.

Height: 60-70 cm.

Turkistan Onion:

The main attraction of this flower is the leaves. Their imponent size gives a beautiful shadow to the soil, maintaining it wet and moist. Flowers are salmon-pink colored, and the stem is thick and juicy.

Name: Allium karataviense

Blooming: Late spring – Early summer

Flower head: up to 15 cm.

Height: 25-30 cm.

How to grow Allium

When to plant

The best period for planting the onion is at the beginning of autumn. Have you ever wondered why bulbs prefer this period of the year? The reason is that they need warm soil to start to develop their root system, however, straight after that, they will need cold temperatures to enable the biochemical progress that will allow them to flower later in spring.

Where to plant

Allium is not picky at all, and you can choose almost every kind of soil without worrying about the success of the final product. Still, there are a couple of rules that you should follow to avoid any type of failure. This specie needs to grow in sunny areas, avoid dark and too moist places, and remember that this plant needs a sheltered place to protect itself from any hard weather conditions such as winds and hail. The soil should be able to drain the water well to avoid bulb rotting and other diseases.

How to plant bulbs

The first thing you should do is prepare the soil and be sure that it’s light, fertile and permeable. If you see that some of those points are not achieved, the easiest way to solve it is to add some sand to your soil. During this process, you can also add minerals and fertilizers you think you may need to help the plant’s growth. Now, after everything is ready, you should start digging holes where you will put your bulb. The depth should be around double the size of the bulb, and the distance between each hole should be about 30 cm. If you live in higher parallels, we may suggest you add some turf on the top of your bulb to avoid ice crust formation during the harshest conditions.

How to plant seeds

Whether you are willing to plant your Allium during the spring (February-March), we highly recommend you to use seeds and remember that you need to keep them in a refrigerator for at least two months (stratification). Once the right season comes, and the temperature is about 13°C (55°F), feel free to sow them on the chosen area. After a period of around three months, you should see first germinating seeds, but consider that it will take 2 to 3 years to reach the full adult size.

How to take care of Allium

Watering and fertilization 

Allium that grows outdoors in the ground usually never shows the lack of watering, which means it’s a tolerant plant that can keep you worry-free if you need to leave your place for a week or so. You might consider watering it during the morning, as it avoids thermal stress for the plant. The only thing you should be aware of is overwatering, as bulbs can quickly rot and kill your plant.

Usually, you don’t need to give fertilizers to this plant, you’ve read already about how though Allium is! In case your soil is poor, and you need to enhance its mineral content, then we suggest you use high Potassium fertilizer as it’s the main mineral which presence in Allium’s growth is fundamental. The best source of Potassium is wooden ash; it’s cheap and easily accessible. The best period to start using fertilizers is as soon as the first sprouts appear out of the soil.

After flowering

Once the flower is fully flourished, you can consider the deadheading, but we suggest you keep it till thoroughly dried, as those flower heads look attractive!

Those plants are perennial and can last up to 5 years. Don’t worry about leaving the bulbs in the ground during the wintertime. Allium doesn’t need any special care during cold periods.

How to propagate Allium


You can use the seeds from your favorite plant to reproduce the variety you’d like to in your garden. The seeds should be collected once the flower is turning brown. After the gathering, you can put them in a bag and then in a refrigerator waiting for the next suitable sowing period (February-March).


Whenever you pick-up your bulbs from the ground for storage, you can notice that there are some new offsets around your original bulb. You can use those bulbs to propagate your mother-plant by carefully detaching them and planting them in a new spot.


Some sorts of Allium can produce little bulbs in the flowers’ center. Those bulbs can be pinched off as soon as the plant has reached complete maturity. After that, you can treat those bulbils as regular bulbs. It will take 2-3 years before the plant will reach her full size.

Problems and Diseases with Allium

Allium can be affected by many different diseases. One of the main problems is during the bulbs’ storage period in the winter, the bulb softens and then dries up. To avoid that, some flower growers recommend keeping the bulbs at a temperature of 40-42°C for at least 12 hours before storing them.

Onion white rot

This disease is the enemy number one of all the onion crops worldwide. The main problem is that it’s symptomless and can be easily overlooked. Today we don’t have any white-rot resistant crop, so all we can do is just trying to control it. The best way is to plant seeds directly or buying a certified bulb. If your plant already has this disease, we strongly recommend you wash the soil off your boots or any tool you were using in the contaminated part of the garden before you touch any other plant. The affected onions can still be consumed, just cutting off the rotten part.

Downy mildew

It’s a fungal disease that’s usually spread by air as spores transmit it. The main target of this fungus is the plant’s leaves. The wet weather and leaf wetness is a perfect breeding environment for this disease. You can recognize it by discolored spots on the upper part of the leaf, spots’ color varies from white-grey to light-yellow. There are no chemical solutions to control this fungus, but you can still apply some golden rules to avoid its spread. Try to avoid a dense disposition for better air circulation and water in the morning instead of the evening to let the plant dry out fast. The leaves you see with that kind of fungus are better to pinch off and throw away from your garden.

Onion Fly

This insect is also a widespread disease in the Allium family. During the late spring, flies appear around those onions and lay eggs on the plant’s lower leaves. After the eggs hatch, the larvae start to dig tunnels until the flower’s bulb and begin to feed on it. In only one season, those maggots can pupate at least once and give life to a new generation of larvae that will continue to feed on the same bulb. You can recognize the beginning of this problem by the appearance of brown leaves. There are no known solutions for this disease, but once you spot the problem, we recommend digging the affected plants and burn them. The onions, in this case, are not edible. 

Design and Compositions

An unfortunate feature of this ornamental plant is the early death of leaves, which spoils the garden’s general appearance. We recommend you to plant flowers around, which will hide the unattractive appearance of wilting leaves. Landscape designers widely use this flower in various compositions, in flower beds, in rockeries and single plantings. If you choose Allium varieties with different flowering periods and flowers of different shades, you can organize a beautiful composition in the garden that will bloom during the whole summer. For the decoration of the borders, we suggest you use the low-growth varieties. Allium is often grown, cut and dried to form bouquets and compositions. When dried, you can decorate a room all winter. The best neighbors to complement your bouquet’s beauty will be Peonies, Delphiniums, Irises, Poppies and Lupins.

If you buy Alliums from the shop, the best practice is to cut diagonally the end of the stem with a very sharp knife. Please put them in clean water and place them in a spot where the sun shines all day. They require almost no care, but remember to water them!