A shout out for Alliums

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Purple Allium growing at Hidcote Manor, Lawrence Johnsons Garden. Image by Ron Porter from PixabayPurple Allium growing at Hidcote Manor, Lawrence Johnsons Garden. Image by Ron Porter from PixabayAllium bulbs are lovely in spring flowering borders, and excellent cut flowers.

Do yourself a favour this autumn and plant some eye-catching flowering alliums, they are indispensable in the late spring and early summer garden, where they flower for ages alongside the last of the daffodils and tulips, and before the first irises burst into bloom.

Alliums can be long-lived and are easy to grow, plus they are great cut flowers and the seedpods are stunning for dried arrangements. 

Allium is a large genus of bulbous herbs which smell of onion or garlic, and belong to the amaryllis family (Amaryllidaceae). Species are found in most regions of the world except for the tropics, and New Zealand and Australia. They include some of the most ancient of cultivated crops, such as garlic, onion, chive and leek, and others which are popular garden plants cultivated in perennial flower borders all over the world.

Given their lineage, gardeners often wonder if including them will make their flower borders smell like a salad bar, but there is no need to worry, the scent is only noticeable when the leaves are bruised or crushed.

In the late 1800’s Russian botanists began collecting some of the spectacular alliums from Central Asia, and introducing them to avid horticulturists worldwide through the Imperial Botanical Garden in St. Petersburg. The British were also captivated by Alliums, and their expeditions to find new plants yielded many more interesting alliums.

Allium' Purple Large' Picture courtesy www.hadeco.co.zaAllium' Purple Large' Picture courtesy www.hadeco.co.zaThe commonly called “florists allium” is a garden hybrid which produces  tall flowering stems in late spring and early summer, topped with spectacular globular clusters consisting of hundreds of small lavender, purple, pink, or white flowers. The foliage is fine and grass-like and can be strappy, hollow or tubular, depending on the cultivar.

Sadly, in South Africa we do not have the beautiful range of alliums available to gardeners overseas, and we have only a single indigenous one, Allium dregeanum, which grows +-35 to 80cm tall and produces lovely white to pink flowers in summer.

Look out for Hadeco’s ‘Purple Small’ and ‘Purple Large’ pack of Allium bulbs. They produce large globes of tiny lilac-purple flowers; and purple large can reach heights of 1 to 1.5m tall.

Uses:

Members of the onion family are unappealing to rodents, and that's a real plus in regions where these little critters are an ongoing challenge. Planting species of the onion family around the garden will go a long way to repelling them.

All members of this genus are cultivated worldwide, and all parts of the plants are edible, although only the bulbs and leaves are usually consumed. However, species that are bred specifically for their flowers are not very palatable.

In the Garden & Home:

Alliums are great garden plants because they don’t take up a lot of space and will bring colour and height to any garden. Their tall slender stems and globular blooms are great for adding contrast in the flower garden, working rather like exclamation marks in mixed flowerbeds. Weave them in drifts through sunny to shady borders, or combine them with feathery grasses for dramatic effect. And, if space is limited, plant them into pots with other flowering bulbs and annuals.

Few plants can provide the ‘wow’ factor that alliums do in full bloom, and if you garden with children, be sure to include alliums - they will be intrigued, and especially by the giant varieties.

When using them as cut flowers, make a clean cut with a knife when less than half of the florets are open. Only when you damage the stems will you smell the typical onion odour, so before you arrange them, trim the stems diagonally and place them in water to soak for a while.

Once the flowers are finished blooming, leave the decorative seed heads on the plants for their sculpture appeal. The seed heads will last well in any arrangement without the need for a sealer.

Cultivation/Propagation:

In South Africa allium bulbs are planted into garden beds in autumn when the soil has cooled down. In the winter rainfall regions plant them in full sun, but in other parts of the country, like freesias and hyacinths, alliums prefer some shade.  A few hours of full morning or afternoon sun would be perfect. Avoid planting on very windy sites, or the tall flower stems will need staking.

Alliums are very hardy to frost and low temperatures, and can be planted in any average garden soil with excellent drainage. Dig the beds over thoroughly to a spades depth, and adding some compost to impoverished soils will give them a good start. If you are growing them in pots, use a good potting soil with some added compost, plus a generous amount of washed river sand for drainage.

Do not add fertilisers and avoid using fresh manure at this stage as these may burn the bulbs. Rather feed later with a specialist fertiliser for bulbs. Hadeco bulb food is specially formulated by leading Dutch flower bulb growers, with slow release nitrogen and essential nutrients it promotes the development of strong roots for vigorous growth and abundant flowers. Its composition also makes it an ideal food for all blooming plants, including annuals and perennials, so treat your bulbs to the right stuff this season, it’s worth it!

Often it is recommended that the bulbs be planted just underneath the soil, however, if you want to leave them in the garden as a perennial, plant the bulbs at least twice the depth of the bulb, spacing them according the planting instructions for your variety.  

Although alliums are quite drought tolerant, to get the best out of your flowering varieties during their growing season, water regularly and deeply, soaking the beds every 3 to 4 days, rather than sprinkling them with small amounts of water daily.

Alliums can look quite messy when they are dying down for their dormant season, and if you want to grow them as perennials, you will need to continue to water and feed the bulbs while allowing them to die down naturally in the garden. This is very important, as this is when they store up reserves for next seasons flowers. To disguise this short but messy stage in their growth cycle, plant allium in between other perennials which have dense and interesting foliage, but which are low growing. The bulbs can be left undisturbed in the soil for many years. Mulch the dormant bulbs and make sure you mark the places where they grow, so that they are not accidently damaged or dug up in summer.

Alliums can be grown from seed and can seed themselves in the garden; however, it will take several years for the plants to flower.

Problems, Pests & Diseases:

If grown correctly, alliums have no serious pests and diseases

Warning:

All species contain organic compounds which give them a distinctive odour and taste, and although these are safe for humans, they can cause toxic reactions in your pets so keep Allium plants away from them.