Upon hearing the word Allium – edible bulbs such as pungent garlic, onions, shallots, leeks and chives immediately spring to mind. Here is a guide to growing Alliums, as well as what to know and some particularly special Alliums to add to your collection.
However, aside from the culinary allium bulbs there are also a vast array of highly decorative bulbous perennials with ornamental flowers. These beauties range from petite, suitable for rockeries or window pots to towering back of the border varieties with gigantic pom-pom heads. Quite literally there’s a bulb for any size of garden, pot or balcony; with horticulturalists adding to this already huge choice on a regular basis.
History of Alliums
The culinary alliums have been cultivated for millennia and indeed Allium sativum (garlic) was used by the ancient Egyptians, Greeks and Romans as a traditional medicinal remedy. Pliny (AD23-79) the Elder listed the complaints that could be improved by using garlic in his vast work – Naturalis historia.
However, it wasn’t until the mid-19th century that the more showy species of the allium family were used in ornamental gardens.
About the Hardy Allium Bulb
Allium bulbs obviously vary in size depending upon the variety grown but all have one thing in common – they are incredibly easy to grow. In fact, they’re the perfect plant for the novice gardener. Once you have planted a few in your garden you’ll never want to be without them again!
The allium flowers themselves are slightly sweet in scent and attract numerous bees, butterflies and other pollinating insects to the garden. However, the pungent taste and smell of alliums when either brushed against or crushed puts off scavengers including deer, vole, rabbits and squirrels. The bulbs may occasionally be dug up by foragers but again will usually be left unharmed due to the smell. All in all a win-win situation for any gardener who loves wildlife but also appreciates a colourful garden!
The majority of these beautiful perennials bloom from late spring to early summer (predominantly during the months of May and June), during that time in the garden when the early spring colour has drawn to a close and before the main summer flush has occurred. This makes them a valuable asset to the gardener interested in continuous vivid bursts of colour throughout the seasons. An exception to this is the beautiful egg shaped drumstick Allium sphaerocephalon that flowers in the months of July or August.
Allium flower heads maintain their vibrant colouring for a few weeks and then change to green as the seed pods form. By July most of the flower heads have turned a golden straw colour with ripe black seeds starting to tumble out. These can either be left on the plants or removed and dried for winter decoration. I personally feel that leaving them in situ makes the garden feel too autumnal.
These spectacular architectural gems come in a vast range of shapes and intense hues from deep purple (Globemaster), pinkish-red (Red Mohican, Forelock), light and dark pinks (Eros, Oreophilum) to pure blues (Caesium) and whites (Ping Pong, Silver Spring) to name but a few. There’s even a yellow gold allium – Allium moly; the cultivar named Jeannine has the biggest umbels of this species.
How to Grow Allium Bulbs
– although not fussy about soil type it’s really important that the bulbs are placed in free draining soil otherwise they’ll just rot; if necessary add grit to the planting hole and a good compost to improve the soil structure.
– if your soil is heavy clay and prone to water logging then container growing is definitely the way to go. The bulbs will be very happy in a deep pot with good drainage and a good peat-free multi-purpose compost. Remember to keep the ultimate height of the plant proportionate to the depth of your pot.
– the bulbs thrive most when planted in full sun but some varieties will tolerate a small amount of partial shade. Although the plants enjoy a moist well drained soil, they are drought tolerant once established.
– this may sound very obvious but remember to plant the taller varieties towards the back of your border and the smaller to the front! A sheltered location is preferable for the taller varieties so that they don’t get damaged by the wind and then they won’t need staking.
– the foliage grows before the flower heads appear and then starts to dieback fairly rapidly; often before the blooms have opened completely. Because of this, it’s best to grow the bulbs amongst perennials or even ornamental grasses that can camouflage the yellowing leaves as they wither and die.
How and When to plant Allium Bulbs
– Allium bulbs should be planted in the Autumn at the same time as other spring flowering bulbs such as tulips, narcissi and iris. The optimum planting time is early Autumn September to October. However, if this isn’t possible the bulbs will still flower the following year even if planted as late as December (weather permitting) but potentially for a shorter length of time.
– As mentioned earlier the bulbs come in a vast array of sizes. An easy rule of thumb is to plant the bulb at least as deep as the bulb is high but preferably twice the depth and distance the bulbs 2x bulb width apart. This works whatever the size of the bulb.
– if the ground is extremely dry when planting – water in lightly.
* When handling allium bulbs it’s best to wear gloves as they can cause irritation to the skin.
Aftercare of Alliums once in the ground
The plants are very easy going and don’t require much maintenance. However, if spring is particularly dry, the allium, like any other plant, will benefit from a good drink once the leaves have started to form.
After the first year it’s worth feeding the plants with a tomato fertiliser (or any other high-potash liquid fertiliser) bi-monthly during the flowering season; ie. From when the small buds first appear to end of flowering period.
Let the leaves die back naturally, as with other types of bulbs, to help it store energy through photosynthesis for the following year.
Aftercare of pot grown Alliums
The leaves of pot grown bulbs need to be left to yellow and shrivel just like those grown in the ground (see above). It’s best to repot the alliums each year during early autumn into fresh compost. If this is done annually the plants won’t require any fertiliser.
Alliums as Cut Flowers
Allium flowers make fantastic cut flowers lasting a long time in water, up to a fortnight, and their stiff stems make them extremely easy to arrange. Adding a splash of bleach to the water in the vase helps to reduce the pungent garlicky/oniony smell that is emitted once cut.
….and finally A Few Really Quirky Alliums!
Allium ‘Red Mohican’ – with a height of up to 36 in (90cm) this unusual maroon drumstick flower has tiny white flowers on its tips and a punky tufty area at the top of its head – hence the term Mohican
Allium sphaerocephalon ‘Hair” – height up to 24 in (60cm) with grass like leaves that look like hair emerging from purple flower umbels. A truly crazy but rather attractive looking flower for something that’s just a little out of the ordinary!
Allium ’Green Drops’ – up to 28 in (70cm) high – with a stouter stem than “Hair” this flowers is just as weird and bizarre. Mini-florets grow on curly stalks out of the chunky principal flower.
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