{"id":10384,"date":"2022-05-13T09:00:33","date_gmt":"2022-05-13T07:00:33","guid":{"rendered":"https:\/\/www.gardensillustrated.com\/?p=80467"},"modified":"2022-05-13T09:20:14","modified_gmt":"2022-05-13T07:20:14","slug":"alliums-how-to-grow-and-when-to-plant-them","status":"publish","type":"rss_feed","link":"https:\/\/c01.purpledshub.com\/gardensillustrated\/rss_feed\/alliums-how-to-grow-and-when-to-plant-them\/","title":{"rendered":"Alliums: how to grow and when to plant them"},"content":{"rendered":"

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By Abigail Whyte\n \t\t<\/p>

Published: Friday, 13 May 2022 at 12:00 am<\/p>

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Onions, leeks, chives and garlic are edible members of the Allium<\/a> family, a genus distinguished by the simple flower umbels that are usually arranged in the shape of a dome or a ball.<\/p>\n

Alliums are mainly native to the northern hemisphere with a few species found in South America. How many allium species there are remains unclear. In her authoritative 1992 book, Alliums<\/em> (Batsford Ltd), Dilys Davies writes that there are between 800 and 1,000 species, but subsequent research suggests that there may be no more than 750.<\/p>\n

In the garden, the most popular alliums are those with tennis-ball flowers on the top of tall stems. Drifting on a cloud of grasses or punctuating a parterre, they are at home both in formal gardens and naturalistic planting schemes. Allium hollandicum<\/em> \u2018Purple Sensation\u2019 is the flag-bearer for this group, but there are forms with larger flowers in a range of purples and mauves.<\/p>\n

IN BRIEF<\/strong><\/p>\n

What<\/strong> Genus of about 750 flowering bulbous plants \u2013 informally known as\u00a0the onion family and characterised by a distinct smell that varies in intensity between species.<\/p>\n

Origins<\/strong> Most come from the temperate climates of the northern hemisphere, particularly Europe; fewer from Central Asia and South America.<\/p>\n

Size<\/strong> From 10cm to 1.2m tall with flowers up to 45cm in diameter.<\/p>\n

Conditions<\/strong> Species for the cut flower trade are more needy, but most will flourish in well-drained soil in full sun.<\/p>\n

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Not all alliums have dense, spherical flowers. Allium cernuum<\/em> has loose flowers made of pinky-mauve bells that dangle from dark pedicles in June.<\/p>\n

With so many species in the wild it is not surprising that new ones are still being introduced into cultivation. Allium litvinovii<\/em> has recently been found growing in Uzbekistan and Kyrgystan, and is starting to be available in specialist nurseries. The intense blue flowers make it very appealing.<\/p>\n

How to grow alliums<\/h2>\n

When do alliums flower?<\/h3>\n

Alliums flowers mainly in early summer, with a few species flowering in late summer. Seedheads can last into autumn.<\/p>\n

Where to plant alliums<\/h3>\n

Most alliums need a well-drained soil<\/a> and prefer a sunny site. If you have heavy clay, dig in plenty of compost<\/a> and horticultural grit before planting them.<\/p>\n

When to plant alliums<\/h3>\n

Alliums bought in pots can be planted at any time but you will get more for your money if you buy them as dry bulbs<\/a> in the autumn.<\/p>\n

How to care for alliums<\/h3>\n

Using plant supports<\/a> or bamboo canes to hold up tall varieties will always look ugly, so grow them through other plants to keep upright.<\/p>\n

The leaves of many alliums, particularly the tall forms, are lax and long and quickly become tatty. By the time the plant is flowering they are often very unsightly. If you have the time (and can be bothered) you can trim off the dead parts, but it is often easier to plant the bulb so that the foliage is hidden by other plants.<\/p>\n

Growing alliums in pots<\/h3>\n

Some of the smaller alliums grow well in pots<\/a> and many grow well in larger containers. Allium caeruleum<\/em>, which has bright blue flowers on 50cm- tall stems in June and July, can be difficult in the garden but thrives on the good drainage and baking heat of a pot in full sun.<\/p>\n

My favourite allium for growing in containers is the short (20cm tall) Allium senescens<\/em> subsp. glaucum<\/em>. The dusky-pink flowers, the size of a ping-pong ball, last for about six weeks in August and September and are surrounded by blue-grey leaves that corkscrew around the stems.<\/p>\n

Alliums to avoid<\/h2>\n

Not all alliums are welcome in the garden; some are invasive weeds that can be difficult to get rid of.<\/p>\n