Weeding sour grass, one thorough patch at a time.

Like many gardeners I have a persistent weed problem.  Well several, but the one I'm battling at the moment is Oxalis pes-caprae, commonly known as sour grass or Bermuda buttercup (though the plant comes from South Africa, not Bermuda).

Oxalis pes-caprae in the garden of someone who says, "Well at least it's green and has pretty flowers."
The picture above is NOT my garden. It is one I saw with shock and horror in Santa Cruz recently. The entire front yard is a sea of sour grass.

While I can get disheartened seeing those little clover-like leaves sprouting up from each plant's single main stem every flipping year, I do see less and less the more and more I pull early in the season - before the bulblets start to form along the stem. I hand pull and try to get as much of the root as I can.

THIS is my garden. I am definitely making progress. This is an area I've worked on for two years.
The worst thing areas are where the Oxalis grows among native blackberry (Rubus ursinus) which is covered with exceedingly thin prickles that get into the skin but won't get out.

I focus my efforts on a couple of garden areas, working thoroughly and repeatedly before the bulblets come. And then do the best I can on the rest. Next year - the same procedure, but many fewer plants in the focus areas. Some areas are almost clear now, just a few plants to pull. But it's a long haul.

To avoid depression, I focus on a defined small patch that I can clear by the end of one weeding session. That way, I can feel a sense of accomplishment when I'm done, rather than the endless torments of Sisyphus's gardening sister. If I find myself scrabbling at the plant tops, not really pulling each plant in Zen-like serenity - I know I've been too optimistic about what I can achieve in one session.

The Patch Weeded - and Beyond. (The slab is for a garden seat TBD.)
It's especially rewarding if you can do a bit of planting in the cleared area afterwards.

I added some local Juncus to the weeded area to help stabilize the down-slope side of the path.
The other thing about adding plants is it gives you a reason to weed there again, with hope for the future. And plantings can help shade out the Oxalis. So I'm told.

And speaking of Oxalis...

I have to be careful not to weed the locally native redwood sorrel, Oxalis oregana!
The yearly task is still daunting but less so every year. The only good thing about sour grass is that it disappears in early spring, so I can live in a pleasant delusion of success — until November rolls around again!

There are other approaches, and I'm working on one of them in this part of the garden - the north slope part. That is to sheet mulch the long snaking path that goes around the contour of the hillside. More on that anon!

Happy new year to one and all - may your gardening year ahead be full of growing - and weeding - success.



Comments

Terra said…
I hand pull oxalis too, and try to get the bulblets out. They are persistant! Happy 2015.
Country Mouse said…
I wish you well with your pulling in 2015, Terra!
Diana Studer said…
you have my sympathy.
But once you have put in your chosen plants, they should outcompete the Oxalis. In Porterville, where I had other plants the Oxalis wasn't a problem. Just on the open, not yet deliberately planted bits.

Here in the new garden I'm battling foreign periwinkle, and indigenous hen and chickens which has Potatoes, as my husband calls them. Great heavy BUNCHes of potatoes! Sigh. Sent six garbage bagfuls to be composted!
Country Mouse said…
I'm still waiting for the out-competing value of planted plants, Diana; a belief which I have heard of before, and work to maintain faith in - next year for sure!
Brent Morgan said…
When you've reached the limit on your weeding, do you find that mowing or hoeing keeps the unweeded ones from being quite so vigorous the next year?

I ask because of memories growing up where we simply mowed the "sour grass" where is stood in our lawn and eventually it didn't come back.
Max Parker said…
I have been fighting this Oxalis the same way, every year, one bit at a time. I read somewhere that chickens go for the bulbs and tops, so when I got my two hens, I put their run over part of the Oxalis area. They really do go for the bulbs! I also let them loose over the other Oxalis areas I see. Hopefully the Salvia spathacea 'Powerline Pink' I planted in the area can outcompete the Oxalis.
Good luck!
Country Mouse said…
I've heard this about chickens, Max - unfortunately not an option for us here. (Terrain too uneven to make movable pens that are coyote-proof for one thing. ) But sounds good - I'm still not sure about outcompeting idea - I see them popping up between things that seem to give shade, but maybe not complete shade?
Brent - I think everything that deprives the plant of resources is helpful. If I can do no more than scrape the top off to remove all leaves and stems, I believe that does make a difference if you really keep on top of it. But that won't eradicate them, not on my land. Just makes the regrowth more sparse - and if I miss a year - then they rebound. I'm glad you were able to get rid of it - maybe in lawns, the dense turf combined with the continual topping was enough to make them give up.
Oh, Country Mouse, I so feel your pain. I blogged about this plant about four years ago because up to that point we never had it here. Then I made the mistake of bringing in some plants from the University plant sale, and boom! Some had hitch-hiked in the soil, and I've been fighting it ever since.

My chickens don't seem to go for it, but they're pretty spoiled. I do repeatedly hand pull, in an attempt to deprive those blasted bulblets of nutrients, but once the baby goats land in spring, I get so busy, it always gets ahead of me. I just need to be more diligent, but I always wince at the first sign of yellow in spring. Good luck!
Country Mouse said…
Ya, I have yet to reach the totally get rid of it nirvana, CVF. I feel your pain too - it came onto our property in some similar way - in a load of topsoil, or mulch, or plant pot… Not sure. But Santa Cruz sure is rife with the stuff.
RMF said…
The only way to really get rid of oxalis is to smother it. lay down sheets of cardboard -- make sure they overlap, because the stuff can grow about a foot laterally looking for a way out -- and weigh it down with clean soil or mulch. It isn't for areas where there are plants you want to save, but it will work in one season, whereas hand pulling takes several before you exhaust the bulbs. In the case of an infestation as bad as the one in the top photo, what have you got to lose?
Country Mouse said…
Thanks for that tip, RMF. Sheet mulching doesn't work for me as I'm restoration gardening and there are desirable plants everywhere! But I am sheet mulching the paths.

It's very encouraging to hear that sheet mulching, properly done to exclude a pathway to the surface, will remove the problem in one season!

BTW the garden in the top photo is not mine.