Rhubarb pie is a popular Indiana dessert. For my family, you can count on a rhubarb pie and strawberry shortcake every year on Mother’s Day.
The edible portion of the plant is the large, tender leaf stalk harvested in late spring or early summer when other fruits are not yet ripe. Rhubarb is a perennial crop and when planting it in a garden it should be placed in an area with other perennial crops to keep it out of the way of the annual plants.
Choose a location where plants can receive full sun and can be cultivated. Two to three plants usually are adequate for the average family.
The leaf blades of the rhubarb plant contain oxalic acid and, therefore, are not edible, either raw or cooked. Poisoning has been reported from eating the leaf blades of the rhubarb plant.
A sandy loam which is well-drained is best for rhubarb. Wetter soils are prone to crown rot. When new plantings are made, the soil should be deeply plowed or rototilled, then worked into a level planting bed. Applications of fertilizer can be incorporated as the soil is worked. A 1:1:1 ratio, such as 12-12-12, should be used at the rate of about 3-4 pounds per 100 square feet of bed area (3-4 teaspoons per square foot) in the absence of a soil test.
If you really want to get your plants off to a good start and have it available, cover the area with 2-3 inches of well-rotted manure. Then plow under or rototill the entire bed area.
For established rhubarb, at the end of the season, side-dress with 1/3 pound of ammonium nitrate per 100 square feet (1 teaspoon per 3 square feet) of bed space to encourage top growth. This will help the plant build up a good reserve of food during the growing season.
Rhubarb is hardy and can be planted in the spring as soon as the ground can be easily worked and planted. Choose crowns which have at least two large buds.
It is very important not to allow crowns to dry out before they are planted to prevent damage. Place the crowns three feet apart in rows that are spaced five to six feet. Use shallow furrows so that crowns will be only two inches below the surface. Space the crowns so that each plant will have 12-15 square feet. Do not set the crowns in direct contact with the commercial fertilizer.
Rhubarb thrives best under clean cultivation because grass and weeds often harbor damaging insects. This means it’s very important to hoe or harrow the bed thoroughly in early spring before growth starts. Be careful to avoid injury to the crowns when cultivating.
For protection from our sometimes harsher winters you will want to add three to four inches of strawy manure around the plants (not on top of crowns) following the first light frost. This helps to control weeds and retain moisture and is also a good source of nitrogen.
For two years after planting, allow all leaves to grow to produce food for good crowns and roots. Harvesting before the third season reduces the stalk size and overall yield of the plants.
During the third season of growth, stalks may be harvested for a four-week period during the spring. During the following years, harvest for 9-10 weeks in the spring. This will allow leaves to grow which will store food reserves for next year’s growth.
Do not remove more than two thirds of the developed stalks from any plant at one time. Harvest rhubarb when stalks are 10-15 inches long by grasping the stalk near its base and pulling it slightly to one side. The stalk should separate easily from the plant. Trim the leaf blades from the stalk and store in a plastic bag in the refrigerator for up to four weeks.
When thinking about rejuvenation, plants should be divided and reset every 8-10 years. Use a sharp spade to divide the crown leaving three or four buds undisturbed in the old location. Old plants which become thick only produce inferior, slender stems.
For more information on rhubarb planting, harvesting and preservation, contact the Purdue Extension Office.