Updated: Mar 30, 2020
Certain events seem to mark the natural cycle of the year for me: they have become my lodestones. Looking out for the harvest moon is one; the first frost of the winter, another; crocuses heralding the real start of spring (snowdrops are too early); the house martins returning from their winter sojourn. And, of course, the first cut of sparrow grass or should I say asparagus.
Asparagus is a perennial plant so new growth will appear each spring after having died down over winter. And it’s this new growth of tender young spears that is so eagerly awaited in our household.
My first recollection of asparagus, however, was not the succulent spears that are best eaten on their own with perhaps just a smidgeon of butter, or at a push, a light vinaigrette. No, my first encounter was in the greenhouse of a friend of my Dad’s who grew carnations and freesias which were packaged up and sent each day to Covent Garden. Andy, my Dad’s friend, (Mr Brundle to me and my sister) grew asparagus for its ferny foliage which seems to complement cut flowers so well.
It took me years to realise that the foliage was the result of the spears which had been left to mature. Even though Andy grew asparagus for its foliage, he never allowed the plants to be stripped entirely. “Decimate, don’t destroy,” he used to say. (Those were the days when decimate meant to take a tenth, of course; its usage has changed over the years.) Leaving a good amount of top growth is vital for the perpetuation of the plant: the foliage feeds the plant during the growing season so that a good crop is available the following year. Which is also true if you grow asparagus for the spears, hence the limited cutting season.
The accepted period for harvesting the spears is for six to eight weeks after the first cut. When the first cut will occur is entirely weather-dependent but it’s generally during April, although you may find some shoots in March. So you will be able to enjoy your crop until well into June. Indeed, the British Asparagus Festival in the Vale of Evesham begins on St George’s Day (23 April) and continues until the Summer Solstice.
To harvest the spears you should cut the stem with a sharp knife 2.5 cm below the surface, when they are no more than 18cm tall. Check the bed every morning – they grow at a rate of knots. A word of warning, though: you should not harvest any spears for the first two years after planting: the plant needs to build up a good, strong root system. Having said that, there are some F1 hybrids which, apparently, can be cut the year after planting: you pays your money and you takes your choice.
I suppose I have jumped the gun a little, talking about harvesting before we’ve even planted anything. So I’ll return to the starting block. You can grow asparagus from seed but to my mind the best way is to buy crowns, which are one- or two-year-old dormant plants. They are widely available from nurseries and by mail order. You’ll need to prepare your asparagus bed very carefully before planting – these plants will remain for 15 years or more, so it’s as well to get the growing conditions as near perfect as you can at the beginning. Asparagus grows best in an open, sunny site; it will tolerate dappled shade but would far prefer to be exposed to the sun. Soil-wise, it’s not over-fussy about pH, although if you have slightly acidic soil you will need to add some lime. What it really can’t stand is poorly drained soil, though. Well-drained, verging on sandy soil, is required. And it must be completely free of perennial weeds: if they spring up after you have planted the asparagus you will undoubtedly damage the crowns trying to get the weeds out, no matter how careful you are.
Dig a trench about 30cm wide and 20cm deep and work in a good bucketful of organic matter, such as well-rotted farmyard manure or compost, per square metre into the bottom of the trench. Cover this with about 5cm of the excavated soil. Now make a 10cm high ridge down the centre of the trench and put the plants on the top: if you have bought crowns, spread the spidery roots out either side. Space them about 45cm apart and, if you have more than one row, leave 45cm between the rows. Cover the plants with the rest of the excavated soil so that the tips are just showing above ground, and water them in well.
After you have planted your asparagus, maintenance is pretty straightforward: hand-weed the bed as and when necessary; mulch with compost in late winter; apply 100g per square metre of general fertiliser in early spring; to prevent damage to the crowns, erect a ‘fence’ made of poles and garden twine and stakes either side of the row to support the top-growth in periods of windy weather (see picture above); cut down yellowed foliage to ground level in autumn. And that’s it!
A word about pests. The most common pests are slugs, snails and asparagus beetle. Deal with the first two as you would anywhere else in the garden. During the growing season, asparagus beetles and larvae can be picked off by hand and destroyed. The adult beetles are about 6-8mm long with six yellow blotches on the wings and a red thorax; the larvae are about 1cm long, are grey-black in colour and have three pairs of legs. Remove and burn any old stems which may be harbouring overwintering beetles at the end of the season.
One of the oldest, most well-known, and widely-grown varieties is ‘Connover’s Colossal’ which has been grown since the 1800s. New varieties have been introduced which, arguably, surpass this trusted favourite. I have to admit that my efforts with ‘Connover’s’ fell far short of being colossal but that might have something to do with the fact that I live in the north of England. I have found ‘Guelph Millennium’, a Canadian-bred variety, copes with the cooler climate well. Although I haven’t grown it, there have been good reports about ‘Mondeo’, bred in northern Germany (it’s early and high-yielding), and also 'Gijnlim'. Also worth a try are two purple varieties, ‘Pacific Purple’ and ‘Stewart’s Purple’; both are very sweet, apparently.
Whichever variety you choose, make sure it’s male: they are more productive than female plants.