Cinthia is a gardener, writer, and manager of a garden center.

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Growing Rhubarb
by Cinthia Milner    

Common garden rhubarb, Rheum rhabarbarum, is a member of the Polygonaceae family. It is an herbaceous perennial vegetable that sprouts from short, thick rhizomes with pinkish-red stalks that resemble celery and has leaves that are labeled poisonous. This somewhat old-fashioned plant is making a comeback. In the language of social media, rhubarb is trending. My mamaw would be so proud, as her rhubarb patch was one of her early spring delights, and her rhubarb pie was one of her most-praised desserts. 

This cool-season vegetable is an ancient plant. Its first recorded use dates back to 2700 B.C. in China. In the U.S. it is first noted as being grown in Maine, around 1790, by an unnamed gardener who introduced it to growers in Massachusetts. By 1822 it had become quite popular, and was sold in produce markets. 

In 1947, a New York court ruled that rhubarb, a vegetable, would be considered a fruit for the purposes of “regulations and duties,” since in the U.S. it was used primarily as a fruit. I have no idea what the botanists of the world think when governments change, in name, what nature has pre-determined genetically, but it is true to say that rhubarb is used primarily as a fruit by most gardeners. It is even referred to by many as “pie rhubarb.” Its tart petioles (the celery-like stalks that are the edible part of the plant) are perfect for pies, breads, cakes, cookies, jams, puddings and, of course, tarts.

Rhubarb is grown primarily in cooler states. Places like Wisconsin, Maine and Washington are famous for rhubarb festivals and are fortunate to be able to harvest it from May until September. In the South, gardeners must take a different approach, as rhubarb does not fare well in dry, hot climates, and temperatures over 75 F suppress top growth, making the plant appear to be dormant. In very hot temperatures, the plant generally dies. Typically a Zone 5 plant, there are some varieties that perform up to Zone 10 (‘Victoria’ and ‘Valentine’), but even these need some shade and mulch to keep them moist.

In the mountains of western North and South Carolina, where USDA Zones range from 5a to 7a, rhubarb performs well, but harvesting stops in in June rather than September, as it does in the North. It can be grown as a perennial in this climate, but as you travel down the mountains toward Charleston and the coast of South Carolina, a different growing method is needed. Many Southern gardeners have been successfully growing it as an annual from seed (the ‘Victoria’ cultivar is best), letting it die when the summer temperatures rise.

Another option is to grow rhubarb in containers. You can do this as an annual, letting it die in the heat of the summer, or move the container to cooler spots, such as the garage or a porch, when the temperatures rise. 

Besides its popularity for use in pies and other sugary delights, this vegetable is high in anti-inflammatory properties and has long been used in natural medicine. It is low in calories, yet loaded with vitamins and is high in potassium and calcium, with almost a third of the recommended daily amount. 

Before one becomes too enthusiastic about this harbinger of spring, it is important to note that the leaves contain high levels of the toxin oxalate, which does not break down enough when cooked to reduce the risk of poisoning. You don’t want to eat the leaves, but feel free to compost them, as the oxalic acid will neutralize during the compost process and no toxicity has been noted. Tested compost piles have shown that the level of acid does not inhibit the microbial action of composting. When you harvest the stalks, strip away the leaves and toss them in the compost pile. If you can’t eat or cook the stalks immediately, they can be easily frozen for later use. 

Don’t be afraid to put this plant in your garden. Many a rhubarb patch has been relegated to a place far away from the garden for fear that it would inhibit growth of other vegetables; it does not. Rhubarb is listed as a good companion plant for the Brassica family, and it does just fine planted in the garden. It does require some room though. A two- to three-year-old plant of the ‘Victoria’ variety can be 4 feet in diameter and 3 feet tall. 

Good drainage is also essential for rhubarb. Plant crowns in raised beds if you can to prevent the crowns from rotting. Plan on harvesting two to three years after the plant is established. Harvest by pulling the stalks, not cutting. Then cook and enjoy!



This article appeared in a previous State-by-State Gardening publication.
Top photo courtesy of Cinthia Milner. Bottom photo courtesy of Samantha Faust.


Posted: 04/30/19   RSS | Print


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