All About Celery and Celeriac

In addition to its own complex and mellow flavour, celery has a magical property that provides enhancement to many other ingredients. This property is best recognized in French cuisine's mirepoix, the combination of onion, carrot and celery that, when sweated in butter or oil, forms the basis of most French-inspired sauces, soups and stews. Cajun cuisine is similarly known for its holy trinity—onion, bell pepper and celery. Celery in one form or another belongs in the makings of any good stock. And, of course, the nutty, earthy, aromatic, and slightly salty flavour of celery if often simply enjoyed on its own.

Though celery is a heavy feeder in the garden, it is not celebrated for its nutrients. It is a good source of vitamin K and sodium, but that's about all. It has long been known for its anti-inflammatory and anti-oxidant properties, but it continues to be most appreciated for the magic it does for our senses.

Historical Record
 

Celery was well known by the Greeks as a culinary aromatic, a garnishing leaf, and a medicinal herb. The Romans quickly adopted these uses, and its name, and started using it as a pesto. Both called it selinon, from which the name we now use was derived. The flavour they enjoyed is likely very similar to what we savour today, but it was from a small, leafy form rather than the large stalk or bulb most commonly used today. It was more like the low-growing, hollow-stemmed celery still used in Chinese cooking.

Leaf celery, also known as soup celery or smallage, is readily available in seed form in catalogues and bulk food stores. It is easy to grow and often survives through the winter. Its seeds were also a popular ingredient in Greek, Roman and East Indian cooking. Leaf celery seed continues to be used as a spice, for flavouring salt, in pharmaceuticals, and in perfume.

Celery varieties with fleshy tender stalks did not appear until the seventeenth century. Requiring considerable experience and labour to produce, they were only available for the wealthy. In the eighteenth century, an easier-to-grow, tender and sweet red celery variety appeared, but for some reason it never became popular.

In the early 1800s, somewhat easier-to-grow varieties were introduced but they only succeeded in marshy soil in cool and wet regions. Transplants needed to be planted into 12-inch-deep trenches that would gradually be filled in with soil. The normally tough and bitter stalks would tenderize and be blanched white in the moist dark soil. After being lifted for harvest, the interior of the plants contained so much dirt that this new vegetable failed to become popular.

In the 1870s, a self-blanching form of celery stalk was released. Golden yellow celery, with lemon-yellow stalks, returned this flavouring to popularity. Then in 1890, an even easier to grow, naturally white version called Pascal was released. Commercial growers quickly adopted it. It is indeed unusual that this classic heirloom continues to be the dominant commercial celery stalk variety.

A bulbous form of celery was introduced in 1827. Easy to grow and easy to store, celeriac, also known as celery root, knob celery and turnip-root celery, immediately became popular in Europe. For some reason it never took off in North America. Only in recent years has it become a standard vegetable found in our supermarkets. This variety of celery forms a very useful bulb between the stalks and the roots. In the store it looks like the innards of a softball. But cut off the spindly roots and peel off the gnarly skin, and the tender and aromatic white flesh is revealed.

Quality Growing
 

All forms of celery prefer to grow in fertile, moist soil with lots of organic matter. They dislike heat and dry, mid-summer conditions. They all grow quite slowly, so require a great deal of patience. In other words, celery growing is not for the neophyte gardener.

Leaf celery is the easiest form to start with. It grows, and looks, like parsley. It can be direct-seeded into an herb garden. But to keep it from being overwhelmed by weeds, it is best to start it as a bedding plant like stalk celery and celeriac (see below). The bedding plants can be set out in the herb garden for leaf-clipping as needed for the kitchen. The plants do, however, have a tendency to bolt, or go to seed. Save and dry the seeds for a fine addition to curry.

Both stalk celery and celeriac can be started in a greenhouse in early April. I prefer this later-than-usual start date in order to minimize exposing rapidly growing plants to the extreme heat of late June and early July. This also reduces the risk of checking (halting) the growth if you need to wait for suitable weather to transplant them out in early June.

Starting with fresh seeds and maintaining daytime temperatures of about 25 C and a night-time temperature of about 18 C speeds up the typical 3-week germination period. Transplant the young plants to larger spaces as soon as their roots start to reach out. Never let them become pot-bound, dried out, or exposed to heat above 30 C. Since germination is so finicky and growing-on so critical, I suggest buying very young plants in mid-May, re-potting them, and carefully finishing them in your home and porch.

For stalk celery, the Utah variety is convenient because it remains compact. Tango better tolerates higher temperatures and drier soil. If you are starting your own seed, look for red stalk celery. It is actually more dark green than crimson, but it is less finicky and certainly has more real celery flavour. For celeriac, Giant Prague is best for large bulbs, and Prinz for smaller bulbs. But I find that all varieties are equally good.

Transplant stalk celery into the garden only after night-time temperatures reliably remain above 10 C (around mid-June). Both stalk celery and celeriac should have at least 12 inches of space around each plant. Water them in well. For exceptional flavour (and to discourage some weeds), sprinkle a quarter-cup of salt around each plant every month.

For growing stalk celery, more than one inch of rain or irrigation water is required every week. If water is inconsistent the plants may develop "black heart." To assist the stalks to self blanch, encircle the stalks with a few layers of newspaper held in place with twine. You can remove this once in awhile to steal a few outer stalks for the kitchen. While the newspaper is off, check your plants for insects and disease. If the stalks are hollow, increase the watering. If they are yellowing, sprinkle additional mature compost around the plants.

For growing celeriac, regular watering is not as critical. The bulbs will be more smooth and tender and less green if you rake a bit of soil over the expanding bulbs.

Harvest celery stalks as soon as they start to become hollow or lose their vigour, usually when the weather starts to cool in September. Cut off the leaves and roots, then wrap tightly in a plastic bag and refrigerate. (They should keep for a month or two.)

Celeriac bulbs will continue to swell as the weather cools. Leave them in the ground until there is a minus-3 C night-time frost predicted. Pull out the plants and cut off the green tops and soil-laden roots. Loosely wrap the bulbs in plastic and refrigerate. (When grown well, celeriac can be stored for about a year.)

Uses for Celeriac
 

I think everyone knows of more than enough uses for typically harsh and assertive celery stalks. However, real possibilities for enchantment come from celeriac. Roast it whole, right in its cleaned skin, to scoop out its unctuous, creamy flesh. Chunks of celeriac cooked in any stew are sure to add a certain je ne sais quoi. A dice of celeriac stirred into a cooking risotto make it simply heavenly. Although delicate, celeriac has the strength to stand up to the sharp vinegar in a pickle. Céleri rémoulade is a classic salad of shredded celeriac tossed with Dijon-mustard-flavoured mayonnaise. Consider expanding upon this dish with some shredded fennel and apple. Celeriac is also tender and mild enough to be served raw, as a crudité.

Recipe

Mashed Potato and Celeriac

By David Cohlmeyer

Makes 4 to 6 servings

This is extraordinary comfort food. Leftovers can be chilled, shaped into patties, and fried for savoury pancakes. Or they can be thinned with stock to use as the base for any number of wonderful creamy soups.

• 5 medium russet (baking) potatoes, peeled and cut into chunks
• 1 celeriac (celery root) bulb, peeled and cut into chunks
• 4 large cloves garlic, coarsely chopped
• 1 bay leaf
• 1/2 cup water
• 3/4 cup cream or milk, warmed
• sea salt, to taste
• freshly ground white pepper, to taste

Toss the celeriac with a little salty water or vinegar to keep the flesh from browning. Place the potatoes, celeriac, garlic, bay leaf and water into a medium saucepan. Bring to a slow boil, reduce the heat, and gently simmer, uncovered, until the potato and celeriac are starting to fall apart, about 20 minutes. Add more water if it fully evaporates before the vegetables are done. (Most of the water should evaporate.)

Pull out the bay leaf. Mash the vegetables with a potato masher or electric beater. (Do not use a blender or food processor, which make it gluey.) Beat in the cream and the salt and pepper, to taste. Carefully reheat over a double boiler to serve.