Posted on

seed spitting weed

How to Remove Oxalis, the Wood Sorrel Weed

First, do you have wood sorrel weeds or another shamrock looking Oxalis?

Besides the bemoaned wood sorrel weed, there are other desirable Oxalis you may want to keep or add to your garden:

  • Redwood sorrel (Oxalis oregana), which carpets the forest floor beneath Pacific redwoods, is one of them.
  • And, silver shamrock (Oxalis adenophylla) hails from outside North America but performs beautifully, even in full sun, in many US and other temperate locales.
  • But, it’s the nasty, creeping Wood Sorrel (Oxalis corniculata) that you may be desperate to remove.

Wood sorrel weed can be pretty. But, it can stress on your plants & soil.

So, why is this one a wood sorrel weed?

Creeping wood sorrel, a non-native plant in the Pacific Northwest. But, it is fairly common in PacNW gardens. And, can also be problematic. For instance, it can play host to diseases like mildew. Plus, it can bring along some food crop diseases. Plus, it’s complex roots can drain soil of nutrients and moisture rapidly. And, it will grow in dense compacted soils. However, it has a strong affinity for loose, sandy soil. That’s because it’s easy to push its traveling stems and roots through these big particles. Furthermore, it grows well in sun & shade, wet or dry. So, it kind of grows anywhere.

Oxalis Wood Sorrel with Mildew Infestation

Knowing how it grows will help you eradicate it.

Wood sorrel weed mostly disappears from view during winter. But, it isn’t dead. Underground, its roots continue to grow strong. Not only do the roots travel along the surface of the soil, but it also spreads itself deeper. Plus, wood sorrel weed throws down tough filigrees of nutrient and water-sapping tap roots that can be tough to dig out. And even worse, this “travel and grow” behavior happens all year long. Piling on, by late Spring, the plants further self-propagate by putting on a display of little yellow flowers from which spitting seed pods form. And, these to disperse more wood sorrel weed progeny.

Finally, a few steps to help get rid of unwanted oxalis.

If this little nasty makes an appearance in your garden, it may take several seasons to eradicate it. And, because it exists through most of North America, it may reappear in the next plant you bring home from a garden sale. So, always check new plant purchases to be sure it isn’t growing in a nursery pot.

Oxalis Wood Sorrel Weed Tap Root Example

But, if you already have it in your garden, try these removal methods.

First: Don’t let it bloom. If wood sorrel weed blooms, the seeds will spread everywhere fast, resulting in more baby plants everywhere.

Second: When you pull it, be sure to get the entire root. That means both the tap root and any roots growing laterally. If you leave any behind, the plant will just regrow. And, use the right tools. If you want to learn more about our favorite garden weeding tools, join our Academy now.

Third: Don’t till an area where this weed has grown. Tilling will simply stir up any residual seeds into the light where they can germinate. And, if you break up any remaining roots, spreading them as you till, your Oxalis weed crop will happily take off again, growing from those chopped up bits you just created.

7 comments on “ How to Remove Oxalis, the Wood Sorrel Weed ”

Hi I have this weed growing throughout my garden when is the best time to fork it up. And also does a bit of
Weed killer eradicate it as my garden is seriously affected by Creeping woodsorrel, Oxalis corniculata.

Beth, fork it up early & often. Also, we aren’t going make recommendations regarding weed killers. Best of luck.

How is it that such weeds as the Shotweed and Wood Sorrel can suddenly appear in what seems like EVERYONE’S garden, when never seen before! The sorrel is a major problem in N.W. gardens, at least from Portland to Port Townsend and across the water in Bothell. Family living in those places tell me of their own plague of sorrel, and I can affirm that! This is the very first time. Where did it come from.

Sarah, They could come on the wind or on the foot of a human or the beak of a bird. They could come in a nursery pot. They could come in potting soil. They could come on a car tire. Plants are adapted to travel in many, many ways.

I despise this weed and all that comes with it

This menace is like a carpet in our garden. We have dug and pulled giant roots of this thing. Are there no natural weed killers that would eradicate it.

I don’t have many weeds, since I practice deep mulch vegetable (& fruit) gardening, however this is my #1 weed and I spend more time than I would like removing it. We are zone 3b with long hard winters and it is one of the first to re-appear each spring. The roots grow very deep and in huge clusters of reddish-white. If you don’ t remove every single bit, what you leave behind will re-grow!

It takes 6 to 8 inches of thick oat or wheat straw to smother it, but even then it will re-appear in a thinner section of the straw. In my large (40 x 60) strawberry bed, I am about ready to use woven landscape textile to cover it all, as it is nearly impossible to hand weed an area that large.

I have heard that vinegar will kill it, but don’t want to risk killing my vegetables/strawberries. And a flame thrower wouldn’t work, for same reason. If only I could find a small dog that would root it out….

Seed spitting weed

Gorse is a dense, spiny, evergreen shrub resembling Scotch broom in appearance. It grows up to 10 feet tall with upright, angular stems that change from green to brown as they mature.

Its spreading branches end in sharp spines and have stiff spine-like leaves about 2 inches long.

Leaves have 3 thin leaflets which become spiny as they mature. Spines are also found in the leaf axils.

In February its yellow, pea-like flowers begin to bloom. Flowers grow in clusters near the ends of branches.

When ripe its hairy, brown seed pods burst, spitting seeds up to several feet. Seeds are smooth, shiny, and olive green to brown in color.

. Once established, Gorse spreads rapidly, crowding out other plants and forming dense thickets. Gorse has a high oil content and a growth pattern of dry, dead vegetation at the center of the shrub. These two factors create a serious fire hazard.

It grows best in sandy or coarse, gravelly soil. It likes gravel bars, fence rows, river banks, open areas and grasslands. From there it has the ability to encroach upon agricultural or recreational lands.

This plant produces seeds prolifically; the bursting seed pods scatter seed for several feet. Animals, machinery, and water also carry the seed. Seeds remain viable in the soil for up to 40 years.

    The best control is to prevent infestations from occurring, never allow Gorse to set seed. The most effective control programs for Gorse will include a combination of herbicides, burning, cultivation or mowing.

For small sites with only a few plants, dig up the plants, or use a weed wrench to pull them up. Be careful to remove as much root as possible, so the plants will not re-sprout.

Mechanical control, such as mowing or brush cutting is ineffective, since gorse plants re-grow all times year round.

  • For selective control of gorse in agricultural settings (pastures, hayfields, etc.), an herbicide containing the active ingredient aminopyralid may be a preferred choice. Aminopyralid products will not harm grass and can be used around livestock (provided all label precautions are followed).
  • When using herbicides be sure to read and follow all label instructions and obey all label precautions. (Note: pesticide product registration is renewed annually and product names and formulations may vary from year to year.
  • To minimize any harmful impact on bees and other pollinators, timing is important. Ideally, treat plants before blooming. If treatment after blooming is necessary, do control work early in the morning, or in the evening when bees are less active.
  • For information about the biological control of this or any other noxious weed, see the WSU Extension Integrated Weed Control Project

Download our Flyer or visit Washington State Noxious Weed Control Board Here. Photos by Beki Shoemaker, Pierce County Noxious Weed Control Board.