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Rhubarb

Rhubarb is a perennial vegetable that grows well in most of the United States. Rhubarb is used in pies, tarts and sauces. Rhubarb should be planted at the end of one side of the garden where it will not be disturbed since it may be productive for five years or more. A half-dozen plants will provide enough rhubarb for a family of four.

Recommended Varieties

Red Petioles (leafstalks)

Canada Red (long, thick stalks, extra sweet)

Cherry Red (rich red inside and out)

Crimson Red (tall, plump petioles)

MacDonald (tender skin; brilliant red)

Ruby

Valentine (petioles 22 by 1-1/2 inches, good flavor)

Green Petioles (leafstalks)

Victoria (shaded with red)

When to Plant

Plant or divide rhubarb roots in early spring while the plants are dormant. Planting seeds is not recommended except in extremely southern areas of the United States.

Spacing & Depth

Plant the roots with the crown bud 2 inches below the surface of the soil. Space the roots 36 to 48 inches apart in rows 3 to 4 feet apart. Good garden drainage is essential in growing rhubarb. Planting on raised beds ensures against rotting of the crown. Working plenty of well-rotted manure or compost into the rhubarb bed before planting greatly increases production.

Old roots may be dug and divided to make new plantings. Cut the roots into four to eight pieces. Each piece must have at least one strong bud. To improve vigor and leaf size, many gardeners divide the old plants and establish a new planting after at least 5 years of full harvest. Plantings older than this tend to begin crowding themselves out. Dig the roots of the most vigorous, healthy plants to establish a new bed the spring before the old planting is to be discarded.

Care

Cultivate shallowly as often as necessary to remove weeds. Apply a complete garden fertilizer before growth begins in the spring and side-dress with a high-nitrogen fertilizer in late June. Except in poorly drained sites, organic mulches help moderate soil temperature and moisture. Irrigate during extended dry periods. An application of manure or compost is beneficial in late fall or early winter. Do not cover the crowns.

Harvesting

Do not harvest rhubarb during the first year of planting. Newly set plants need all their foliage to build a strong root system. Stalks may be harvested for 1 or 2 weeks during the second year and for 8 to 10 weeks (a full harvest season) during the third and subsequent years. Harvest in the fall only when the plants are to be discarded the next season. To harvest, pull the leafstalks from the plant and trim off the leaf blades. The leaf blades contain large amounts of oxalic acid and should not be eaten. To keep the plants healthy, vigorous and producing well, remove only about one-third of the leaves from a plant at any one time.

If seedstalks and flowers develop during the spring and summer, cut them from the base of the plant as soon as they appear and discard them. Vegetatively propagated, named varieties usually have been selected to produce fewer seedstalks than cheaper, seed-produced plants. The petioles (leafstalks) are of the highest quality (maximum color, flavor and tenderness) in early spring. They should be crisp and fairly thick. Yield and quality are highest if petioles that have just reached full size are harvested before any coarse fiber can develop.

Common Problems

Rhubarb curculio, a snout beetle, bores into the stalks, crowns and roots of rhubarb plants. It also attacks wild dock, a weed that is prevalent in many areas of the country. Destroy all wild dock growing around the garden. Treat the base of plants with a suggested insecticide. Burn badly infected rhubarb plant parts in July after the beetles have laid their eggs.

Questions & Answers

Q. A severe freeze has damaged my rhubarb. Can I safely eat the leafstalks?

A. No. The leafstalks will be of poor texture and flavor and oxalic acid may have migrated from the leaf blades.

Q. Why do my rhubarb plants send up seedstalks and produce small leaves and leafstalks? The petioles are not as large as they have been in previous years.

A. These conditions may result from excessive crowding, old plants or low soil fertility. Allow more space between rhubarb plants, divide parent plants and fertilize regularly. Some seed-propagated plants produce small foliage and many seedstalks even under the best conditions. Buy only named, vegetatively propagated varieties; or get divisions from another gardener who has a high-quality planting.

Selection & Storage

Rhubarb is as hardy as a weed. It is a very beautiful garden plant, with huge extravagant, lush green leaves and pink or red stalks. Rhubarb is an ancient plant as well. Chinese rhubarb has been traced back to 2700 BC. According to folklore, Chinese doctors recommended it for its medicinal qualities as a laxative, to reduce fever and cleanse the body. Rumor has it that rhubarb grown in the United States does not have the same medicinal value as "true rhubarb" or Chinese rhubarb.

Harvesting of rhubarb in Illinois generally begins in mid-June with a second harvest in August. The deeper the red, the more flavorful the stalks are likely to be. Medium-size stalks are generally more tender than large ones, which, may be stringy. For storage, first trim and discard the leaves. The freshly harvested stalks can be kept in the refrigerator, unwashed and wrapped tightly in plastic, for up to three weeks.

Nutritional Value & Health Benefits

There are several different varieties of rhubarb grown all over the world and used in a variety of cooking preparations. One characteristic consistent with all rhubarb is the toxicity of the leaves and roots. The rhubarb leaves contain high amounts of oxalic acid, a toxic and potentially deadly poison. Only the stems are edible, although the first crops were grown for the round pouch of unopened flowers, which was cooked as a delicacy (in northern Asia it is still raised for this purpose).

Nutritionally, it is low in calories and very acidic (pH 3.1). The acid is offset by the addition of sugar, which also increases the calorie count. Rhubarb is 95 percent water and has potassium and a modest amount of vitamin C. Although rhubarb can be tough and stringy, it does not contain a great deal of fiber, only 2 grams per cup. Unfortunately the high calcium content it supplies is bound by oxalic acid and so it is not easily absorbed by the body. Don't count on rhubarb as a source of dietary calcium.

Nutrition Facts

(1 cup diced, uncooked)
Calories 26
Dietary Fiber 2 grams
Protein 1 gram
Carbohydrates 6 grams
Vitamin C 10 mg
Vitamin A 122 IU
Folic Acid 8.7 mcg
Calcium 105 mg
Potassium 351 mg

Preparation & Serving

Rhubarb requires the addition of sugar to combat its extreme tartness. The early pink-stems seem to produce the best flavor for cooking. Rhubarb, or "the pie plant," is often considered a fruit, but it is actually a vegetable (leaf stem). It is prized for it's mouth-puckering tartness which adds zest to pies, tarts, cold soups, jam, and a host of other desserts.

Many other flavors are flattered by the sourness of rhubarb. In the US it is most often teamed up with strawberries and baked into pies and tarts. A typical English preparation would use ginger, while the French may puree it into a sauce and serve it with fish.

Home Preservation

To freeze: Chop into 1/2-inch pieces, spread them on a sheet pan and place in the freezer. Once frozen, slide the rhubarb into heavy-duty plastic freezer bags. Seal tightly and put back into the freezer. Packed this way, rhubarb will keep for up to six months, and can be measured from the freezer bag.

When cooking fresh rhubarb, use a vegetable peeler to remove any brown or scaly spots. Peeling the entire stalk is unnecessary, simply trim the ends and wash and dry the stalks.

Always use a non-reactive pan for cooking this high acid plant. Use anodized aluminum, stainless steel, Teflon coated aluminum or enamel-coated cast iron cookware.

Rhubarb cooked in reactive metal pots (aluminum, iron, and copper) will turn an unappetizing brown color. Metal ions flaking off the pan will interact with acids in the fruit to form brown compounds that darken both the pan and the rhubarb.

Recipes

Rhubarb Strawberry Topping
This sauce is excellent as a topping for ice cream, pancakes, waffles, pound cake, and a bowl of fresh fruit, gingerbread or yogurt. It will keep in the refrigerator for up to 4 days.

10 stalks rhubarb, trimmed and cut into 1-inch pieces
4 cups hulled, quartered strawberries
1 1/2 cups sugar
1 cup orange juice
Zest of one orange, grated
Zest of one lemon, grated
1/2 teaspoon vanilla extract

  1. In a large heavy saucepan, combine all ingredients and stir well. Bring to a boil over medium-high heat.

  2. Reduce heat and simmer for 10 to 12 minutes, skimming of foam as it collects.

  3. Remove from heat and allow it to cool to room temperature. Cover and refrigerate. Serve cold or warm. Reheat if desired. Keeps for 4 days in the refrigerator. Makes 8 cups.