How do you kill invasive Oxalis?

Jane McGary via pbs
Mon, 12 Oct 2020 12:31:01 PDT
I have a similar problem with Oxalis obtusa. I find there is no way to 
eliminate it (it got in when the tiny bulblets must have become hidden 
in the tunics of desirable bulbs I was moving), but I can keep it down 
by waiting until the foliage is fully developed and then reaching into 
the sand it's growing in and pulling out handfuls of the roots and 
bulbs. At this point I think the new bulblets haven't yet formed on the 
stoloniferous roots. It's growing in among plunged pots, so just in pure 
sand. If it gets into the pots through the drain holes, I pull it out 
and mark the pot for replacing the soil once the bulbs go dormant. I use 
color-coded labels for that kind of note. As for using glyphosate 
(Round-up), I've read that Oxalis is resistant to it. I've seen a 
herbicide at a farm store indicated to be "Oxalis and spurge killer," 
but spotted spurge can be killed with glyphosate.

Jane McGary, Portland, Oregon, USA

On 10/12/2020 11:58 AM, Pamela Slate via pbs wrote:
> Thanks much for your input!
> The two spp. at O. sternorrhyncha and O. purpurea possibly 'Garnet.' The
> latter has purple leaves that lay flat on the ground with a pink flower.
> I am still wondering how mature bulbs can be killed effectively. I have
> always been an organic gardener, have never applied toxic chemicals and
> that is why I asked the solarization question (I've solarized before).
> I'd consider a chemical if I could be sure the mature bulbs would not
> survive but would prefer another method. There are hundreds of bulbs in
> that bed and I have dug up many in the past but now there are too
> many.....especially tiny ones.
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