Gardening: Know your onions

Ornamental onions 'make an impact in beds and borders.
Ornamental onions 'make an impact in beds and borders.
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David Overend has a few tips for those leafing through catalogues ready for the coming year.

It’s cold outside – and there may well be a lot of winter weather still to come – but now’s the ideal time to play the optimist.

Cheer yourself up – it’s still several hundred days to next Christmas – but it’s still possible to look ahead. Get online or use a specialist catalogue and order a bag of summer-flowering bulbs to ensure you get them in good time for planting in spring.

You can wait until later in the year and then buy them from garden centres, but getting them from a specialist gives you far more choice.

Lilies are still among the most popular of all the summer-flowerers, but there are many, many more equally stunningly lovely bulbs on offer and ready and able to light up the garden in summer.

Go for giant ornamental onions like Allium aflatunense, giganteum or elatum; lovely, languid irises; fascinating foxtail lilies such as Eremurus himalaicus or robustus, and crinums with their gigantic pink trumpet flowers – definitely a plant for the flamboyant gardener.

And while you’re waiting for the postman to deliver the goods, prepare for the appearance of spring bulbs.

Snowdrops are already flowering and some gardeners have been enjoying the sight of very early daffodils since the end of the old year, but there are many more bulbs yet to bloom.

Bulbs fall generally into two groups: spring-flowering (which are planted in the autumn) and summer-flowering (which are planted in the spring). A more accurate grouping, however, divides bulbs into hardy and tender varieties. As a rule, spring-flowering bulbs are hardy bulbs. These bulbs are planted in the autumn, generally before the first frost, and can usually survive the cold winter months.

Many hardy bulbs, such as daffodils, can be left in the ground to flower year after year.

Most summer-flowering bulbs are tender bulbs which cannot survive harsh winter conditions and are planted in spring. They need protection until the threat of frost has vanished.

To enjoy these bulbs year after year, they should be dug up in autumn and stored indoors over the winter. A notable exception is the lily. Many summer-flowering lily varieties are quite hardy.

Sometimes you can gamble, successfully, leaving tender bulbs in the soil over winter; if they are covered by a thick mulch and the ground doesn’t get waterlogged or frozen, they may well survive. It’s a gamble but...