HAVE a nasty weed rampant in my garden - oxalis - which has a white
flower. The bulbs are covered in little bulblets that pop off into
the dirt as you dig them up and they spread even more. I have managed
to keep some areas at bay by smothering them with newspaper and
bark, but it is incredible how far they will creep. The worst place
it occurs is in the vegetable patch where it has spread through
compost. If hoed over, it just pops up again the next day. My elderly
neighbour has told me he got rid of his by dabbing the leaves with
creosote which burnt the bulbs. As I can't imagine this would do
the soil any good, I was hoping you could make another suggestion.
are several types of oxalis that can be a nuisance once they get
established. It sounds as if your problem is probably Oxalis
incarnata, though its flower tends to be pale lilac rather than
white. However, control is the same regardless of type.
Probably the easiest
way is to use one of the many glyphosate-based weedkillers on the
market, such as Roundup, Glyphosate 360 or the convenient ready-touse
types like Zero or Weedmaster Blue that come in trigger packs and
need no mixing. The active ingredient (glyphosate) is absorbed through
the leaves and travels through the plant to the bulbs, killing them,
as long as enough of the product is absorbed.
Apply the first spray
when there's a lot of oxalis foliage present to absorb the active
ingredient, then spot-spray regrowth regularly as it appears. If
you're vigilant you should reduce the problem, but it can take time
Glyphosate breaks down
in the soil and doesn't affect nearby plants, as long as you don't
get it on their foliage or stems.
Another product effective
against oxalis is Escort, but it's generally more expensive and
less widely available than glyphosate.
Gardener, Issue 155, 2004, Page 26
Reproduced with permission from the former Weekend Gardener magazine. The views expressed here are not necessarily those of the RNZIH.