I have good news and bad. The good? Your plant is edible
and even delicious. The bad? It’s also a weed!
By Larry Hodgson
Question: I’m finding this plant in my garden for the second year in a row and it’s now everywhere. It has very odd-looking leaves. Do you know it? And how do I get rid of it?
Nicole Godbout
Answer: Yes, I do know it. In fact, I know it all too well, having waged a war against it in my own garden.
It’s sheep sorrel or red sorrel (Rumex acetosella). Backyard foragers love it, as it has very tasty sweet and sour leaves you can easily add to salads and sauces. Plus, it’s rich in minerals and vitamins. And it’s traditionally used to treat diarrhea, sore throats, fevers, hemorrhaging, and as a diuretic. Also, it’s one of the ingredients of the Essiac anti-cancer remedy, currently quite popular.
So far, so good!
But it’s also a weed. And very invasive one, at that. One that is very hard to control.
A Plant that Gets Around
Sheep sorrel comes from Eurasia, but was introduced to North America many generations ago, probably by accident.
This plant is remarkably prolific. It produces abundant underground rhizomes with buds appearing here and there along their length. A single plant from seed can produce, in just 2 years, 3,500 plants. That’s enough to cover 40 ft2 (4 m2) of surface!
And it’s not just out-of-control rhizomes that cause a problem. Female plants (sheep sorrel is dioecious and produces male and female flowers on separate plants) can produce up to 450,000 seeds a year.
This explains how this imported plant is now so thoroughly acclimatized throughout all of North America except the extreme North.
Mine Came in Contaminated Soil
Sheep sorrel first showed up in my own garden in a load of topsoil, supposedly of top quality. Within two weeks, it was popping up everywhere in my brand-new vegetable and flower beds. My suggestion? When you bring new soil into a garden, find a sunny spot and make a pile out of a few shovelfuls of it. Then keep it moist for a few weeks. Don’t start applying it to your garden until you have a better idea what is hiding out in it!
What Is Sheep Sorrel?
Getting the Names Right
- Sheep sorrel = Rumex acetosella
- Garden sorrel = Rumex acetosa
Sheep sorrel is a dioecious perennial in the Polygonaceae family. Garden or common sorrel (R. acetosa), the one used in French cuisine, as in the classic “soupe à l’oiseille,” is a close relative. It also escapes from gardens, but nothing like to the extent of sheep sorrel.
It produces a 4 to 6 inch (10 to 15 cm) rosette of small, smooth arrow-shaped leaves, the lower ones often with distinctly pointed lobes.
Tiny flowers appear in summer on upright branching stems, often leafless. They reach about 20 in (50 cm) in height and are reddish on female plants and yellow-green on male plants. The blooms are wind-pollinated. Seeds (on female plants only) is a small, red, 3-sided capsule.
It has a very long taproot reaching deep into the soil and making it hard to pull out.
Although this plant is edible and commonly harvested by backyard foragers, its lemony-tasting leaves get their taste from oxalic acid which is slightly toxic. It should be consumed in small quantities only. In large quantities, it is toxic to livestock as well.
It Grows . . . Everywhere!
Like many naturally weedy plants, sheep sorrel adapts to just about any environment. It tends to be most common in very acid soil on dry sites. However, that isn’t because it needs extreme acidity or dry conditions. It grows perfectly well in alkaline soils and moist ones as well.
It does like lots of sun. In fact, one way of eliminating sheep sorrel is to shade it out by using taller plants with dense foliage.
If sheep sorrel has any redeeming quality, it’s that it will grow in environments, such as on mine tailings, where few other plants can survive. It can therefore help recuperate contaminated soils.
Getting Rid of Sheep Sorrel
And that’s the crux of the matter. How do you get rid of a plant that spreads so far so quickly!
By the time most gardeners realize they have a problem with sheep sorrel, it’s often already out of control. Trying to dig it out sometimes works, but can also be a waste of time, as the roots are deep. Inevitably, some break off and are left behind, then baby plants sprout everywhere. Still, if you keep at it . . .
Just try to dig out all the rhizomes as best you can! Even one left in the ground will start a new colony!
I removed mine by digging up the beds and sifting the soil with a plastic bakery tray with a grid bottom. That was moderately easy, because the soil had only been freshly added and the plants hadn’t rooted in yet. I was amazed by huge quantity of rhizomes that has sprouted in such a short time.
You could also try occultation or killing the plant by covering that section of garden a black tarp that lets in no light. Since that cuts off all access to sunlight and the plant needs lights to grow, that will starve it of light. Leave the tarp on for a full 18 months to be sure.
I’m not a great admirer of herbicides, even organic ones, as they can easily damage nearby plants. However, if you paint them onto the leaf rather than spraying them, you can kill the sheep sorrel with harming its neighbors. More than one treatment may be necessary.
Sheep sorrel: curious but tangy leaves, and a nasty habit of wanting to take over gardens. I think it’s a plant most gardeners could do without.
Oxalic acid – yes, that is why I was instructed to not eat too much of it. I am not so keen on it anyway, and was only eating it because it was there. Regardless of oxalic acid, I would not eat enough to make it go away.
Showed up 4 years ago (1,200 feet of road front is my bane…it was “snowing’ dandelion seeds yesterday…my life is ebbing away trying to prevent damage to my native grassland project from being overwhelmed by the “no mow even if my yard is full of invasive European plants). The Rumex spreads like wildfire. I used to garden…now I just weed.
What good advice about new soil! I brought some in to top up some veggie beds this year and was surprised by all the weeds, including perennial ones, that came with it. It is easy to deal with because it is contained in raised beds. Years agoI received a load of new soil containing horsetail. I thought it was pretty and left it to spread! I will be doing the soil test from now on!