If you’ve been a reader of this column for a while, you know that I’m a big fan of rhubarb.
Every year, we add more of it around our place, due to the fact that it holds up well in the heat, sports beautiful large leaves, takes little care, and comes back with a flourish each spring. It’s one of my “go-to” plants that I use as a harbinger of warmer weather. It’s almost magical to see a bare spot of ground, where last year’s plant proudly stood, start to have walnut-sized pinkish-green buds rise from the soil. When the conditions are right, it erupts into sudden growth, putting out stalks and leaves at a dizzying and gratifying pace.
The truth is, even if we didn’t harvest the stalks for use in Maggie’s incredible rhubarb-strawberry-orange rind pie, we’d still have plenty of “pie plant” around because of the beauty it brings to our yardscape. I like rhubarb as a substitute for calla lily plants that I’ve seen grow as far north as Montreal. While they flourish in the warmer months, they can’t survive winter — at least without digging up their tubers and storing them properly. Rhubarb comes back each spring, has deep green leaves that are sizable and provide considerable shade around the base of the plant. Because they are a mounded plant, they fit in well with other plants and shrubs.
But what is most compelling of all about this beautiful plant is that it is truly perennial. The top dies back at fall’s first freeze. Perhaps a better description is that the leaves “melt.” What was once a sizable green leaf just a day or two before is now shriveled up and lying on the surface of the soil like a deflated balloon. You can remove the dead leaves, or let them decompose into the soil. By the time in warms up in the spring, you can be easily fooled into thinking that you’ve lost your rhubarb. There is very little left to clue you in that there is a root mass just under the soil’s surface poised to burst forth with the season’s display!
Like many plants, rhubarb does a great job of collecting rainfall and directing it to the center of the plant. The large leaves are moderately waxy, which is readily seen as water beads up on the foliage when they encounter rainfall or a dose of water from your watering can.
For all its pluses, it does have a few offsets. First, slugs tend to take up residence in the center base of the plant because it stays moist and cool — even in the hottest of days. The plant is so robust that it can take slug damage in stride. But if our slimy friends bother you, you can resort to picking them off by hand, or using a bait method around the base. Second, rhubarb contains oxalic acid — especially the leaves.
So, how could rhubarb be the mother of invention? Like many inventions we take for granted today, an unintended product can result either from a mistake, or an unplanned outcome. There’s an interesting story about one man’s interaction with rhubarb that resulted in a modern-day product we use around the house — Bar Keepers Friend!
Like many of you, we have stainless cookware with copper-clad bottoms. We really like the cookware, but it can get discolored on the bottom, as well as having food and oil scorch onto the interior and the “nooks and crannies” where the handle attaches to the pan. We have found no better product for quickly cleaning up and renewing our pots and pans than Bar Keepers Friend. What’s its secret ingredient? It’s the same compound that is found in rhubarb leaves — oxalic acid.
In 1882, a man in Indianapolis was cooking rhubarb in a tarnished pot. After he was finished cooking the rhubarb, he was pleased to find that his tarnished pot was now clean and shiny. Lucky for us, this rhubarb aficionado turned out to be a chemist. Using rhubarb’s active ingredient, oxalic acid, he formulated a talcum-smooth cleanser and sold it to his city’s taverns. The cleanser went over so well with his customers, that the product became known as “Bar Keepers Friend.” Its active ingredient, oxalic acid, works very well with brass, copper, stainless steel (our sinks respond really nicely!), porcelain, and ceramic surfaces.
By the way, Bar Keepers Friend is still made in Indianapolis and is easily found at retailers both across the U.S. and in many parts of the world. That ought to make rhubarb proud!
The fact that rhubarb’s leaves contain a significant amount of oxalic acid warrants a few observations. While rhubarb leaves are comprised of about one-half of a percent oxalic acid, the substance can also be found in many plants including Brussel sprouts, chives, and cabbage. In fact, Wikipedia lists 40 vegetables that contain varying amounts of oxalic acid — ranging from trace to higher concentrations.
You might be asking, what is oxalic acid? Is it harmful? How is it commonly used?
Like many things, oxalic acid can be harmful in larger quantities. The stalks of rhubarb have a low concentration but the leaves have more. Fortunately, the leaves don’t taste good! I compost the leaves and avoid feeding them to my chickens.
Oxalic acid is commercially available for manufacturing uses and can be found in some products like cleansing powders, rust removers, wood bleach, concrete brightener, polish and sealant for marble, and as a fixing agent for textile dyes. If you use a product containing oxalic acid, take precaution not to breathe it in. It’s highly irritating to the throat and mucous membranes, and in various concentrations, can cause kidney stones, joint pain — and in high concentration, even kidney failure.
Here’s another important use to mention: BEEKEEPING!
Oxalic acid is commonly used as a miticide to control the parasitic Varroa mite that infects honeybee colonies. The mites attach themselves to the bodies of developing bees, and suck out the bee’s hemolymph (an insect’s equivalent to blood). You could say that vampires, in the form of the mites, are very real to bees. As you can imagine, this is quite detrimental to the bee colony, and if a high enough concentration occurs, bee deformities and even death of the colony can occur. In fact, the Varroa mite has been associated with Colony Collapse Disorder (CCD).
This mite exerts the single greatest negative economic impact to the beekeeping industry. To control it, oxalic acid is incorporated into a sugar-water mixture at just over three percent concentration. The mixture is then dribbled over the bees and between frames. This is not toxic to the bees, but it is to the mite. Another application method is using vaporization whereby oxalic acid is heated on a small hot surface that has been inserted into the main opening of the hive. All other openings are sealed. The vapor permeates the entire hive, coating all surfaces. The bees tolerate this well, but the mites are killed.
So, as the weather warms in a few months, the cycle of life will continue as your rhubarb plants from last year erupt through the soil. This is one of the most visible — and dependable — reminders that another growing season is coming and soon you’ll need sunscreen! For some rhubarb “edutainment,” visit youtube.com/dirtfarmerjay, and enter “growing and harvesting rhubarb.” You’ll see firsthand how additive and productive this great plant is!
Also, keep an eye out for the upcoming fruit tree, berry and grape vine pruning demonstrations, scheduled for Saturday, March 5. There will be two demonstrations, one at 10 a.m. in Erda, and the other at 1 p.m. at a location to be announced. Details will be posted in the Bulletin Board section of this paper in a few weeks. Whether you’ve attended before, or it’s your first time to see how to get the maximum health and productivity from your fruit trees and berry plantings, come and join the fun.
Jay Cooper can be contacted at firstname.lastname@example.org, or you can visit his web channel at youtube.com/dirtfarmerjay for videos on gardening, shop skills, culinary arts and landscaping.