Eat the stalks, not the leaves! Wise words to adhere to when you’re going for the over-the-top tart perennial known as rhubarb (Rheum rhabarbarum). This member of the Polygonaceae family has perfectly edible stalks that look similar to celery, but has leaves that are quite poisonous. Rhubarb leaves contain some seriously high levels of oxalic acid, which is a nephrotoxin and can lead to kidney damage, and even potentially death if enough of it is consumed.
This striking vegetable, although often considered a fruit by many, is thought to have originated in China, as far back as 2700 B.C.E as an ingredient in many healing remedies. Around the 1st century the Romans and Greeks were also using rhubarb to treat various illnesses. In the 13th century Marco Polo was noted to have uncovered the rhubarb in his travels. As the centuries passed, the bitter rhubarb was brought to Europe via the East Indian trade as an important ingredient in medicinal tonics. By the 18th century, rhubarb had made its way to North America and was grown and used mainly for medicinal purposes. It wasn’t until the 19th century that rhubarb was utilized as a culinary item.
Generally we think of rhubarb as red in color, and think color is indicative of sweetness. However, rhubarb can be freckled pink and even come in green. Often the green rhubarb produces higher yields and sweetness is variety (not color) dependent. It just seems the red varieties are more popular with people and so that’s what we see in the stores more often than not. I do agree that the crimson hues add some nice color to the dishes rhubarb is added to.
Whether you like your rhubarb red, green, or with a few pink freckles, growing it is easy peasy. However, there are few things you should consider before planting. It is a perennial and will come back each year (some live to 20), so make sure you have a dedicated space for it in your garden. Also, don’t harvest any stalks during the first year of growing so the rhubarb can become established. This will help you have better success in years to come. Rhubarb does best in locations that have winters with temperatures that go below 40°F and where summer temperatures aren’t excessive.
To plant your rhubarb, pick a spot that’s in full sun and has well-drained fertile soil. Rhubarb is a heavy feeder and will need compost added to the soil, but don’t add chemical fertilizers because direct contact with nitrates can severely damage your plants. It’s best to plant 1-year crowns in the spring as soon as you can work the ground, before any growth begins, or in the fall after dormancy has set in. Plant the roots 2” below the surface of the soil and 4’ apart from other plants. As the years pass and your rhubarb grows, dig up and split the roots every few years. This should be done when plants are dormant.
Keep your rhubarb well-watered and your garden weed free. This will help you grow supple stalks and keep pests and disease at bay. If you find your stalks are thin, add additional compost to feed your rhubarb. When the stalks are over 1’ it’s time to harvest. Simply grasp the base of the stalk and pull it away from the plant with an easy twist. However, be sure to leave at least 2 stalks per plant so your plants continue to produce. When harvest is over, and the stems die back, remove any debris and cover your plants with compost after the ground freezes. Do note that rhubarb shouldn’t be eaten if it was damaged by severe cold. As mentioned before, the rhubarb leaves contain oxalic acid, and if your plant is exposed to severe cold the oxalic acid can migrate from the leaves, making the stalks toxic.
If cared for and harvested properly, rhubarb has many nutritional qualities. One stalk (55 grams) of rhubarb has 12 calories, 0 grams of fat and protein, and 2 grams of carbohydrates (1 gram of which is dietary fiber). Rhubarb is an excellent source of Vitamin K-1, and a good source of Vitamin C. It also provides us with Vitamins A, E, B-1, B-2, B-3, B-6, and B-9, and the minerals calcium, copper, non-heme iron, magnesium, manganese, phosphorus, potassium, and selenium.
Another benefit to rhubarb comes from the pigments the red varieties contain. Plants with red pigments contain lycopene and anthocyanins. These serve as cancer preventers and cardiovascular health and immune system boosters. The one thing to know about lycopene is that it’s stored in the plants’ walls. Therefore, in order to make it bioavailable, you must first cook the rhubarb. So cooking the rhubarb we shall do! Check out this fun recipe to make with your next batch of rhubarb.
Rhubarb Coffee Cake
2 cups pecans – finely chopped
4 teaspoons cinnamon
¼ cup butter
1 teaspoon rum flavoring
1 cup rhubarb – chopped into ¼ inch pieces
1 cup almond flour
1 cup coconut flour
½ teaspoon baking soda
¼ teaspoon salt
½ teaspoon of ginger
1 teaspoon of cinnamon
1 teaspoon of nutmeg
4 eggs – slightly beaten
¼ cup cream
3 tablespoons butter
1 vanilla bean (split and scrape out -use only the portion that has been scraped out. The pod can be discarded or used to infuse warm milk or cream for another use)
Combine all ingredients
Preheat oven to 350°F
Grease a round 9-inch cake pan
In a large bowl mix together flours, baking soda, salt, and spices
Add in remaining ingredients, except for rhubarb
Using an electric mixer beat until fully combined
Sir in rhubarb
Pour batter into prepared cake pan
Sprinkle with topping
Bake for 35 minutes
Insert toothpick to test for doneness. If toothpick comes out clean, cake is done. If not, cook for an additional 5 minutes
Remove cake from oven
Let rest for 10 minutes
Cut and serve. Enjoy!
Note: to make the cake sweeter you can add honey to both the batter (¼ cup) and topping (2 tablespoons)
There you have it, the rhubarb rundown. While once only used for medicinal purposes, this prized perennial is great in the garden and the kitchen. Simply skip the leaves and go straight for stalk and you can’t go wrong with this wonderful and vibrant vegetable.
Choose My Plate.gov. US Department of Agriculture. SuperTracker. https://www.choosemyplate.gov/tools-supertracker
University of Minnesota Libraries. University of Minnesota. Rhubarb. Illustration of rhubarb, from Pierre Pomet, Histoire generale des drogues. Page: 50. https://www.lib.umn.edu/bell/tradeproducts/rhubarb