Oxalis, an invasive plant

“I think I’ve tried everything to get rid of just one weed: wood sorrel† It is a disaster in my garden there are everywhere and so many that I can no longer grow. Every spring I kill myself to the task on my knees to remove these little onions, but nothing helps on sunny days they invade me. If anyone has an effective tip, I’ll take it. †comment posted by Chantal on the article dedicated to weeding)

Len replied to Chantal: “ I have the wood sorrel in my garden between the cobblestones, and not just on sunny days. The only solution I have found is boiling water (and yes) as soon as they appear and at least at the beginning of flowering. Which doesn’t prevent them from always coming back here or there, but it prevents them from being invaded by them. †

Ok, the solution is effective (short term), but while it is acceptable in a garden, it would be catastrophic for soil life in a garden.

Well, I then promised to write an article on the subject… Here we are.

But instead of an effective trick, let’s see what this plant tells us, the lessons to be learned from it in order to limit and ultimately overcome its presence, without harming the Earth and its inhabitants.

First, let’s start by getting to know this invasive plant that is common in gardens (aside from Chantal’s comment, I get questions about it regularly).


l’wood sorrel is a genus that groups several (about 400 in the world) perennial species of herbaceous plants, spontaneous or cultivated, of the family of Oxalidaceae

The plants of this genus are particularly characterized by trifoliate leaves (but some cultivated species have 4 petals), heart-shaped and 5-petal flowers, appearing in April-May for most species, and of different colors depending on species and season .

Here are some species that were spontaneously or first grown, but have now become naturally spreading weeds:

  • sheep sorrel or cuckoo bread (Oxalis acetosella), growing spontaneously in the forest, in the shade, with white flowers veined with mauve
  • wood sorrel (Oxalis corniculata) characterized by reddish leaves and small yellow flowers. It develops in disturbed areas: vacant lots, embankments, worked fields or gardens…
  • wood sorrel (Oxalis stricta), common in cultivated areas and forest edges, and increasingly in lawns on acidic soils. The flowers are yellow
  • oxalis articulated (oxalis articulata): First grown in gardens, this oxalis has become a wildflower (pink in color) often found along paths
  • Goat’s foot or Bermuda oxalis (Oxalis pes caprae): like the wood sorrel, this cultivated species is now found almost everywhere in Mediterranean gardens and in nature
  • oca of Peru (Oxalis tuberosa), grown for its edible tuber
  • purple wood sorrel (Oxalis triangularis), its purple leaves make it a plant often grown for ornamental purposes… and spreading everywhere

The fruits are capsules containing a significant number of seeds, causing uncontrollable proliferations.

Distinguish wood sorrel from clover

Wood sorrel, also called “false clovers,” is often confused with clover.

But the shape of the leaves makes them quite easy to distinguish: the clover has round leaves while the leaves of the wood sorrel are heart-shaped.

wood sorrel leaf
Wood sorrel leaves are made up of 3 heart-shaped leaves
cloverleaf leaves
Clovers are completed

And the bloom will clear any doubt if you still have some:

wood sorrel flower
Oxalis flowers are composed of 5 petals
Flowering Clovers
Small clover butterfly flowers

What does the presence of oxalis indicate?

The obvious presence of this plant on land is a sign of erosion.

Due to the lack of sufficient storage capacity of the soil, there is no longer any organic matter present.

This phenomenon mainly occurs in the soils left bare in winter or summer

The soil should therefore never be left bare (at least not for too long), but on the contrary covered with straw, hay, shredded material or even dead leaves to provide carbon.

That said, this plant is beneficial for the soil and aerobic microbial life (it aerates the soil)… in short, it “fixes” our mistakes…

(source Gérard Ducerf – Encyclopedia of bio-indicator and medicinal plants)

Lessons to be learned (preventive measures)

Avoid Growing Wood Sorrel in Your Garden

Admittedly, it is a beautiful plant, but you could soon regret installing it in your garden!

As we’ve seen, it produces a significant number of seeds housed in capsules… which for certain species will simply “explode” (well… the term may be a bit of an exaggeration, but at least it has the merit of being to speak), spreading a multitude of seeds, which will only ask to germinate, in your garden.

And then you’ll have a hard time getting rid of it.

The first precaution to take may therefore simply be to avoid introducing this invasive plant into your home…

Creating conditions that are not conducive to its development

This plant settles on eroded soils, the result of uncovered land.

The lesson to be learned is simple: don’t leave the ground bare (or at least as short as possible).

To do this, mulch …

You can also grow green manures in the winter on heavy soils.

This way you not only prevent this phenomenon of erosion and thus reduce the chance of invasion, but you also aerate and enrich the soil in your garden (central objective of Mon Potager au Naturel)

It won’t be easy… and I have no miracle method to offer you.

But by arming yourself with patience and especially by protecting the soil of your garden, you should be able to overcome it.

Pull out by hand, in the spring

If the soil is moist, pull out young regrowth as soon as possible and bring in the roots.

You can also trim the foliage regularly at the base to gradually weaken the plant.

In any case, make sure that the seeds do not form and above all mature (it is therefore advisable to act at the latest when the flowers begin to fade)!

Do not use a tiller or tiller

The operation of these machines will have the effect of multiplying the roots and spreading the bulbils in the soil… thus ensuring the spread of this plant.

If you have to work the land to make a cultivation bed, use a Campagnole or a Grelinette instead.

These tools allow you to lift the root systems, if possible with the bulbils (which are basically rhizomes located at the base of the roots), and evacuate them.

Put on in the late summer

At the end of summer, pull up any wood sorrel still in place.

Even if there are still roots in the ground, this will weaken the plant, which will then have to use its reserves for the winter…

Cover the ground

A good mulch (more than ten centimeters thick), maintaining and loosening a certain moisture in the soil (by the action of earthworms and other micro-organisms that take care of the decomposition of these plant materials), will make it easier to remove the plant with its roots and with it eventually its disappearance from your garden.


Yes, wood sorrel is a beautiful ornamental plant…

The leaves of oxalic sorrel are even edible, with medicinal properties (purifying, diuretic, stomachic).

But don’t overdo it: 10g of oxalic acid kills (knowing that 100g of oxalis leaves contain 1g of oxalic acid, you would still have to eat 1kg to succumb to it).

In any case, consumption is strongly discouraged for people with kidney or digestive disorders.

If you’ve tested a really effective method, or just want to share your experience with this invasive plant, do so in the comments section below.

Thank you.