How to Remove Oxalis, the Wood Sorrel WeedOctober 21, 2013
Is your garden carpeted in unwanted Oxalis, aka Wood Sorrel weed?
Oxalis comes in many forms. Think Shamrock, and you’re in the right camp. Redwood Sorrel (Oxalis oregana), which carpets the forest floor beneath Pacific redwoods, is one desirable form. Silver Shamrock (Oxalis adenophylla) hails from outside North America but performs beautifully, even in full sun, in many US and other temperate locales.
It’s the nasty, creeping Wood Sorrel (Oxalis corniculata) that you may be desperate to remove.
Creeping Wood Sorrel, a non-native plant, is fairly common in Pacific Northwest gardens. And, while it can be lovely, it can also be problematic. It can play host to diseases like mildew and some food crop diseases. Plus, its complex roots can drain soil of nutrients and moisture rapidly. While it seems to do just fine in compacted soils, it has a strong affinity for lose, sandy soil through which it can easily push its traveling stems and roots. And, yes, it grows well in sun & shade, wet or dry. (It is a weed, after all.)
Wood Sorrel mostly disappears from view during winter, but its roots continue to grow strong. Not only do the roots travel along the surface of the soil, pioneering new rooted claims rapidly as the plant grows, but also this Sorrel throws down tough filigrees of nutrient and water-sapping tap roots that can be tough to dig out. 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 to disperse more progeny.
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.
First: Don’t let it bloom. If it 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.
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.
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