"Derek Carver" wrote in message
...
I am posting this message just in case you are suffering this weed on your
lawns.

We had at our house when we arrived an old Edwardian Tennis Lawn. This
has
been used as a play area for many years but when the kids left home we
decided
to work on it and turn it into a croquet lawn. But there were large areas
of
field woodrush.

Experts who came in to help said there was nothing on the market that
would
kill this weed.

But my old gardening books recommended nitro-chalk in order to create
conditions disliked by this plant. I duly applied it. There was no
instant
effect, of course, but two or three years later I was suddenly aware that
there
was no field woodrush anywhere to be seen and, as yet, it hasn't returned
although it is in other parts of the garden that I didn't treat.

Frankly I can't think what the purpose of the 'nitro' was other than to
encourage the grass to re-colonise the area. Its disadvantage was that
the
only form in which I could buy this was pelleted, which meant that the
fertiliser tended to burn the grass for a while where it was concentrated.
It
didn't show up, that much, of course, but in order to keep up with the
treatment (and not let the lawn return to its acid state again) I think I
will
just add the chalk - assuming one can buy chalk in its powdered form.

Derek Carver
Oxshott, Surrey

Yes Woodrush is quite persisent but actually I quite like it, the flowers
are very attractive in a quiet sort of way. Some of it's bigger relatives
are excellent ornamental plants esp. Luzula niveum, Luzula sylvatica and its
variegated form.
Field woodrush occurs typically on acid impoverished lawns that are mown
very close.
Why does Nitro-Chalk work? - Well it is Calcium nitrate and as you've seen
it's powerful stuff. You are adding a big slug of nitrogen which is boosting
the growth of grasses at the expense of the Woodrush which doesn't tolerate
competition. You are also raising the pH because Calcium nitrate is a basic
salt.
If you really must get rid of Woodrush it will also help if you set the
mower a bit higher - still mow as frequently or more if you want and collect
the cuttings when the Woodrush is flowering and setting seed.
Feeding and higher mowing will also help against several other lawn weeds
and mosses.

Rod