On 4/4/10 7:47 PM, MiamiCuse wrote:
South Florida zone 10b.

I have planted some Costus (Ginger family) in a 50' long planter area.
However the weeds are growing like wild fire and I am unable to keep up with
pulling them. I wanted to use some weed killer to control the weeds (clover
leaf type, see a pic here
http://www.biology-blog.com/images/b...-leaf-3100.jpg ), but
have heard that weed killer will also kill plants that have rhizones which
my Costus is.

Is this true? Is there a better way to control the weeds beside hand
pulling?

Thanks,

MC



Take a piece of the weed -- not merely one leaf -- to a "real" nursery
(not a lumber yard or hardware store) for identification. This might be
oxalis instead of clover.

There is a specific weed control that severely burns oxalis,
sufficiently to kill most of it, without harming other plants (except
for spotted spurge, another weed). Sold under various brand names, it
contains ammonium thiocyanate, which quickly decomposes into a urea form
of fertilizer; sodium thiocyanate is about as effective. Any oxalis
plants that survive must be hand dug, for which I recommend the use of a
paring knife. Be alert! Oxalis readily forms seeds, which are not
affected by the chemical; the thiocyanates act only on growing foliage.

If your weed is indeed clover, hand pulling is the best control. Do
this before it flowers, and you won't have to repeat. Try to leave some
of the roots in the soil; they are an excellent source of nitrates for
nurishing other plants.

--
David E. Ross
Climate: California Mediterranean
Sunset Zone: 21 -- interior Santa Monica Mountains with some ocean
influence (USDA 10a, very close to Sunset Zone 19)
Gardening diary at http://www.rossde.com/garden/diary