Rhubarb in the Garden and the Kitchen

Rhubarb in the Garden

Rhubarb (Rheum rhabarbarum) is an ideal edible plant for the home garden. The deliciously tart stalks can be expensive at the grocery store, but when grown as an herbaceous perennial, rhubarb is inexpensive, needs very little care, is bothered by few pests and diseases, and is very long-lived.

Although rhubarb is technically a vegetable, it is legally a fruit and is treated as a fruit in the kitchen. Rhubarb sauce, rhubarb pie, rhubarb crisp, rhubarb cake, rhubarb-onion chutney, strawberry-rhubarb preserves, and bluebarb jam have all been constants on my table since childhood. I love rhubarb not only for its flavor but for its beauty in the garden. It is a large, bold plant with gorgeous, robust, deep green, textured leaves that sit atop colorful, long petioles or stalks. It deserves a place in more perennial flower beds.

Cultivars vary in stalk color from pink to red to speckled to green. The flavor is fairly consistent among cultivars, and there is no correlation between tartness and stalk color. Red stalk cultivars include 'Canada Red,' 'Crimson Red,' 'McDonald,' and 'Valentine.' Red cultivars may produce thinner and fewer stalks. 'Victoria,' a robust green-stalked variety, is a very reliable performer with thicker stalks. ‘Victoria’ is the rhubarb of my childhood and the one I choose to grow more of in my own garden.

Rhubarb divisions and crowns can be found at local garden centers and by mail order. It can also be grown from seed, but it takes a long time, and the seed may not be reliably similar to the parent.

Spring or early fall are the best times to plant. Rhubarb requires a site in full sun with well-drained, fertile soil amended with organic matter such as leaf mold, compost, or well-rotted manure. It is not sensitive to the pH of the soil. The area around the site should be weed-free. Provide plenty of space, about 3 square feet. With our clay soil, you may need to hill up the area for drainage or plant in a raised bed.

Once it is planted, have a little patience. Harvest nothing in the first year and sparingly in the second year. This delay will allow the large leaves to provide sufficient energy for crown and root development. From the third year on, you may start harvesting in the spring to early summer, but remove no more than half of the plant at one time. This cool-season crop will naturally slow down during the hotter days of summer but resume growth as cooler temperatures return. You may continue to harvest, but back off when the stalks get thinner, as this is a sign that the reserves in the crown are depleted.

Rhubarb requires little maintenance. Water it deeply during extended dry periods. Fertilizer helps with growth and large yields. In early spring, apply around the perimeter of the plant either a half-cup of 5-10-10 all-purpose fertilizer (and work it into the soil) or a 2- to 3-inch layer of well-rotted manure.

Mulching suppresses weeds and conserves soil moisture. If a flower/seed stalk appears, remove it by pulling or cutting it off at the base. Otherwise, it will reduce plant vigor and stalk formation. After the ground is frozen in the late fall, apply 2 to 3 inches of straw mulch.

Divide this perennial every 7 to 10 years as you notice it becoming less productive, with thinner fruit stalks and perhaps more seed stalks. In early spring, as soon as the soil can be worked, dig up the entire plant and lift it from the ground. Section the clump into divisions that contain at least one or two buds and a good root system. Inspect the center of the clump for indications of root rot, as this crowded area may need to be discarded. Plant each divided section in a prepared hole so that the buds are upright and 1½ to 2 inches below the surface. Firm the soil around the plant, but don't press directly on the sensitive buds themselves.

Very few pests bother rhubarb. Deer don't touch it. Rhubarb curculio may cause minor damage by puncturing the stalk. This ¾-inch-long beetle, with a characteristic long, curving snout, lays its eggs in the stems of the perennial weed, curly dock. To control this pest, eliminate curly dock from your garden in July after the beetles have laid their eggs. Another pest, rhubarb stalk borer, overwinters in the egg stage on grassy weeds. Eliminate grassy weeds from the area.

The only other potential issue is phytophthora crown or "root rot." Control this culturally by planting only disease-free divisions in a well-drained, sunny site with good air circulation.

Rhubarb in the Kitchen

Wait until your stalks are 10 to 15 inches long, then harvest by holding the stalk firmly and pulling with a slight twist. Do not harvest by cutting the stalks, as this will allow for disease to enter the plant crown. Take your knife to the garden and cut off the leaf as well as the base of the stalk where it attaches to the crown of the plant. The leaves are poisonous with toxic levels of oxalic acid, but can be safely composted.

The leaves may be poisonous, but the stalks are quite healthy as they contain many vitamins, minerals, phytochemicals, phenols, and fiber. Rhubarb is tart and, therefore, is rarely eaten fresh. Cooked with sugar, it makes a delicious sauce that can be eaten alone or served as a topping for ice cream, yogurt, pound cake, or even a pavlova. Rhubarb is usually an ingredient in baked goods like pies, crisps, cobblers, muffins, scones, and cakes. Rhubarb pairs well with other fruits, especially strawberries, blueberries, and cherries. The flavor of rhubarb is refreshing in a beverage such as strawberry rhubarb lemonade. But rhubarb can also be used in savory chicken, fish, beef, and pork recipes. 

Before any food preparation, clean countertops and utensils. Wash your hands with soap and warm water.

Fresh rhubarb can be stored in a plastic bag in the refrigerator for up to two weeks. For longer storage, it can be easily frozen or canned. To freeze rhubarb, wash, trim, and cut the stalks into appropriate sizes for later use. Pack a measured amount tightly into a freezer-safe container, leave appropriate headspace, label, seal, and freeze. It can be frozen with or without added sugar or simple syrup. I store 2- and 3-cup batches based on the amount needed in future recipes, double-bagged in freezer-quality plastic bags.

To preserve rhubarb through canning in boiling water or an atmospheric steam canner, follow only research-based methods and recipes. Rhubarb-strawberry jelly, stewed rhubarb, and rhubarb-pineapple sauce are delicious options.

Whether you choose to use the rhubarb in the kitchen in sweet or savory recipes, rhubarb is sure to provide beauty in your garden for years to come.

For further information on the nutritional value of rhubarb, how to safely preserve it, and additional recipes, see:

• Rhubarb Love it for its Taste; Eat it for Your Health
• Preserving Rhubarb
• Rhubarb Cookbook

Dorothy Morris’s Decadent Rhubarb Cake

Ingredients

Batter:

• 3 cups finely chopped rhubarb
• ½ cup granulated sugar
• ½ cup softened butter
• 1 cup granulated sugar
• 1 egg
• 1 tsp. vanilla
• 2 ½ cups all-purpose flour
• 1 tsp. soda
• ½ tsp salt
• 1 cup buttermilk

Topping:

• ¾ cup brown sugar
• ½ cup finely chopped nuts (walnuts or pecans work well)

Sauce:

• ½ cup butter
• 1/3 cup granulated sugar
• ¾ cup evaporated milk
• ½ tsp. vanilla

Directions:

1. Preheat oven to 350°F.
2. To make batter, combine 3 cups finely cut rhubarb with ½ cup granulated sugar and let stand until the rest of the batter is made. Cream ½ cup softened butter and 1 cup granulated sugar in a mixing bowl. Add 1 egg and 1 tsp. vanilla to butter mixture. In a separate bowl, sift together 2 1/2 cups flour, 1 tsp. soda, and ½ tsp salt. Add flour mixture to batter, alternating with 1 cup buttermilk. Add prepared rhubarb to batter.
3. Place batter in a greased 9 X 13-inch pan.
4. Top batter evenly with ¾ cup brown sugar and ½ cup finely chopped nuts.
5. Bake for 45 to 50 minutes. Remove to a cooling rack.
6. While cake is baking, make the sauce by combining ½ cup butter, 1/3 cup granulated sugar, and ¾ cup evaporated milk in a saucepan. Boil gently for 3 ½ minutes. Remove from heat, cool, and then add ½ tsp. vanilla. Beat sauce well.
7. When cake is baked and while still hot, poke holes in it with a fork and spoon the sauce over the hot cake.

My Favorite Rhubarb Crisp

From the Better Elk Horn [Iowa] Club Cookbook

Ingredients:

Crust:

• 2 cups old-fashioned oatmeal
• ½ cup all-purpose flour
• 2/3 cup brown sugar
• ½ cup butter

Filling:

• 5 cups chopped rhubarb
• 1 cup granulated sugar
• 1/3 cup all-purpose flour
• Dash of salt

Directions:

1. Preheat oven to 350°F.
2. Mix crust by combining oatmeal, flour, brown sugar and butter until crumbly.
3. Pat half of crust mixture in the bottom of an 8 X 8-inch pan.
4. Combine all ingredients for filling and place filling on top of bottom crust.
5. Top with remaining crust mixture.
6. Bake for 30 to 35 minutes or until bubbly.

Note: I usually double this recipe and use a 9 X 13-inch pan. Increase baking time.