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Often regarded as a fruit, but technically a vegetable, this hardy herbaceous perennial is grown for its edible leaf stalks which can be used for jam-making and desserts for several weeks beginning mid-spring. Rhubarb is a cool-season crop and does best grown in the northern third of the U.S. It requires a cold period to break dormancy. A rhubarb plant forms a large mound, almost 3 feet wide and almost as tall. Its huge leaves are supported by stalks that are usually red, but some varieties have green stems.
Rhubarb can be grown in the same spot for many years, so it’s important to choose a location where plants will not be disturbed for several years. The site should be free of perennial weeds, especially quackgrass, and should have good drainage and fertile soil. Prior to planting, cultivate the soil to a depth of about 12 inches and incorporate plenty of organic matter. A full sun location is good, but rhubarb is the only vegetable able to tolerate a half-day of shade. The east side of a building works well, where it can escape the hot afternoon sun.
Plant the crowns in spring, spacing about 3 to 4 feet apart, with the young shoots or “eyes” about 2 inches below the soil level. If planted too deeply, the eyes will rot away. Mulch the crowns well, keep the soil moist, and provide generous amounts of a balanced fertilizer through the growing season. The next spring, top dress the young rhubarb plants with manure or a granular or liquid fertilizer. The more food and water you give rhubarb, the more stalks it will produce and the thicker it will be. There is little danger of overfeeding. Cut off any flowering spikes as they emerge in the spring and summer, and remove any spindly, unwanted leaves as they occur. Apply mulch around the plants after the first frost of fall, but don’t fertilize late in the season. Although best planted in spring, rhubarb can also be planted in early fall, but a mulch should be applied for the first winter.
Don’t harvest any stalks the first year of growth; the second year, harvest a few stalks from each plant. Beginning the third year, harvest for up to two months, but don’t’ remove more than one-half the stalks at any one time so food reserves rebuild in the roots.
The rhubarb crop can be advanced by as much as 3 weeks if covered with loose straw or an upturned pot or pail to protect the developing leaves and stalks from frost damage. Pick the rhubarb when the stalks are about 10 to 15 inches long. Grip each stalk as close to its base as possible and pull them away from the crown at a slight angle. It’s the best practice to pull the stems, not cut them, but if you prefer harvesting by cutting, do so by cutting 1 to 2 inches above the crown, making sure not to cut into the crown. Discard the leaves as they contain oxalic acid, are toxic and should not be eaten. When most of the emerging stalks are thin, usually when weather turns hot, it’s time to stop harvesting.
It is recommended that rhubarb be divided every 4 to 5 years, or sooner if the stalks become thin and spindly. In early spring, cut down through the center of the plant with a sharp spade leaving half the plant intact. The removed portion can be divided and transplanted to a new location, but dust the cut surface with a fungicide and set in the sun for 2 to 3 days to callous and then replant.
Rhubarb is quite free of insects and diseases. A disease called crown rot can occur if rhubarb is planted on poorly drained soil or if new plants are set in the same location where grown previously. A copper fungicide will help in controlling this problem. If any plants die of this disease, they should be removed and care taken to prevent contamination of healthy plants.
Great recipes using rhubarb are plentiful. Here is one of our favorites we want to share.
1 ½ cup brown sugar 2 cups flour
½ cup margarine 1 tsp. baking soda
2 eggs ½ tsp. salt
1 cup sour cream 1 ½ cups diced fresh rhubarb
Cream sugar and margarine. Add eggs, beat well. Blend in sour cream. Combine dry ingredients together and blend with creamed mixture. Fold in diced rhubarb. Pour into a greased 9”x13” pan.
½ cup sugar 2 tsp. cinnamon
½ cup chopped nuts 2 T. margarine
Mix above ingredients and sprinkle on top of cake batter. Bake at 350 degrees for 30 to 40 minutes.