Diarmuid Gavin: Asparagus is the plant that keeps on giving
In 1985 I started my working life in a wonderful shop, Mackey Seeds Ltd, then based in Mary Street in Dublin. It was a true horticultural emporium, a gardening version the 1970s BBC sitcom Are You Being Served? where the employees at London's fictional Grace Brothers department store got up to all types of mischief. Mackeys was full of mischief too… Well, it would have been if I was there, wouldn't it!? But it was also innovative before it's time and full of gardening gems. It was run by a French man with refined tastes - and one of his introductions to mainstream Irish gardening was the growing of asparagus.
At the time, it was regarded as an exotic vegetable and was imported from France as dormant one-year-old plants known as crowns. The truck was met directly from the ferry and Jean Pierre made sure that its contents were immediately distributed to the four corners of Ireland.
While it may be a relatively recent introduction to our shores, asparagus has been cultivated over thousands of years, as far back as the ancient Egyptians and Romans. Although it's a native plant, it has a gourmet reputation of being a delicacy and expensive. It does require patience at the beginning, as you won't be cropping for two to three years while the plant establishes itself. That might seem like a long time but when you consider that these plants can keep giving their precious crop for up to 20 years, you know your time and effort will be rewarded. And asparagus is so good for you - packed with vitamins and antioxidants. So here's all you need to know to get growing:
The crowns look a bit like bulbs with long tails which are the roots. Ideally they like to be planted in well-drained soil in a sunny position. If your soil is very heavy, you're probably better off planting in raised beds. They're in for the long-haul, so be sure about your position as they won't thank you for moving them around. It's also very important to have the area as weed-free as possible before planting, so you are not poking around trying to weed and thereby disturbing the plant's shallow roots once it's in the ground.
Dig a trench about 8in deep and place well-rotted manure or garden compost at the base. Add some general fertiliser to this, followed by a 2in-layer of soil. Next, create a small ridge running along the centre of your trench, about 4in in height. Plant the crown on top of the ridge, buds pointing to the sky, and then spread out the roots so they drape down the ridge. Leave at least a 1-1.5ft between each crown. Cover with soil so that the buds of the crown are just peeping out. Water in and a good mulch will keep the moisture in and prevent them from drying out.
During the growing season you will have lovely ferny foliage - admire but don't touch. Let it die down naturally in autumn to gain the maximum amount of energy back into the crown. When it is fully died down you can chop down the stems to ground level. The two following springs you will be feeding the plant again, and the third spring you should have a healthy crop to harvest.
They don't like drying out, so remember to water during dry spells over the summer. And the tips can be damaged by frost, so keep a bit of horticultural fleece handy to throw over them when frost is forecast. Their main pests are slugs and snails and the asparagus beetle. Vigilance here is key: remove any unwanted visitors by hand. When you cut down the stems in winter, remove them, as otherwise they provide great cover for overwintering beetles. Tomato plants are a good companion plant as they're said to be beneficial in repelling this beetle.
Male varieties produce the most and the best spears. The RHS has awarded 'Connover's Colossal', 'Gijnlim' and 'Backlim' its AGM seal of approval. All of these are good yielders. For attractive purple spears, look out for 'Pacific Purple', a New Zealand variety that is tender and sweet.
Did you know?
White asparagus, enjoyed on the Continent for its delicate flavour and tender texture, is not a variety but a method of production whereby the soil is earthed up on the spears as they grow so that there is a lack of chlorophyll, hence they are white.