Asparagus: bringing up the spear

As Delia warned me, a field of fresh, live asparagus is an underwhelming sight. Where exactly, on the expanse of furrowed earth, is it? Right, got it now. The spears are sporadic and slender and look exactly as if some prankster had bought them in a supermarket and pushed them into the ground to fool me, the visiting townie. It lacks the visual and sensual delight of a hillside thick with ripening raspberries, I have to say, or the lure of a lemon grove, or even the pleasure of looking at a decent patch of pea plants, but this is because with asparagus all the work goes on underground, in the massive network of roots called the crown.

The part we eat (or long to eat in this exceptionally late, weather-blighted season) is the first stem of the young plant. Left to grow unmolested, the tight, almost feathery tip will unfurl into a beautiful fern, go to seed and do its reproductive stuff, though in this field it will not get very far because all the plants are purple-tinged male F1 (first-generation) hybrids of the variety Franklin.

The asparagus harvest is a moveable feast, because the crowns need a rise in temperature to make them venture forth with stems/spears. Some years (such as 1667, as recorded by Samuel Pepys) the spears have started before St George's Day. This year, we are nearly a month behind. Sadly, the crowns are behaving a bit like would-be swimmers on a British beach dipping their toes in the water then withdrawing rapidly, except that asparagus can't hop about shrieking, 'Oh my gawd that's cold, what's wrong with this country?' etc. (What's wrong with the country is that it's a bit too far north for a warmth-loving plant but, as with the grapes of Burgundy and Champagne and Scotland's raspberries, there is a theory that this stress, which lessens the yield, actually intensifies the flavour.)

The crowns become thick and sturdy and can last for over 100 years. I have this on the best authority because my guide is Michael Paske, king of English asparagus-growing, who sometimes gets called in to resuscitate ageing asparagus gardens. (Please don't ask right now, however, as he is, for his sins, also Vice President of the National Farmers' Union.) Michael's oldest plant to date was 120 and perfectly healthy, though not very productive. For a commercial crop, 15 years is really the recommended lifespan. Intriguing, eh?

But what you really need to know about asparagus – the thing that most exercises its producers and vendors – is that the lovely fresh green flavour is so short-lived. Once the plant is cut, the cells continue working and – unfortunately – convert the stored sugar that is the main element of the flavour into starch and tough fibre. Ideally, therefore, asparagus should go straight from field to plate, but in the real world this rarely happens because of the supermarkets' centralised distribution. The subject is a source of frustration to the grower we are visiting today, Columbus O'Donnell, who is in partnership with Michael Paske. 'I've approached various supermarkets asking if we can deliver loose asparagus directly to their branches in our area, so their customers really get to taste it at its best, but it seems that this doesn't suit the system.'

Once the air and ground are warm enough, asparagus can grow eight inches a day in Britain, double that rate in sunny Peru. Its thickness depends on the depth of soil above the root system – shallower crowns create thinner asparagus. Bendy spears – more like bows than arrows – are generally bent by the wind. You have to cut the spears to encourage the crowns to put out new ones, and on Michael Paske's sandy Sussex farm he can sometimes cut three times a day.

Columbus O'Donnell's land is fertile but slow-warming loam. On the day I visited, a team of 10 agriculture students from Belarus were having their first day's work hampered by knives that were going blunt and a lack of asparagus experience. It is this time-consuming, tiring cutting work that makes asparagus so costly, but provided it is fresh, it is well worth the early-season asking price. I took a full plastic bag of asparagus home and ate it four hours after harvest, and I have never eaten better asparagus in my life.

Asparagus – top tips

• Buy it fresh – within 24 hours of picking is best, so look out for farmers' roadside stalls. Use it immediately.

• Cook it quickly – see How to steam asparagus, below.
• Asparagus can be purple, green or somewhere in between, but it all tastes equally good. White, however, does signal a difference –white asparagus is grown with earth banked up over the spears, so it hasn't seen the light of day. It is imported, expensive and subtle-tasting – sometimes the exterior is tough and has to be pared away.
• The thin asparagus called sprue is good if it is a) fresh and b) cooked for an even shorter time than normal asparagus.
• Great matches for asparagus are: eggs, butter, cheese, lemon, pastry, potatoes, tarragon or chervil, salmon, sea trout and all the expensive white fish.
• If you have to keep asparagus for a day or two, try this tip from Mrs O'Donnell: put it in a jug or vase with the stems in water, then store it (carefully) in the fridge.