On Fri, 24 Apr 2009 08:25:55 -0700 (PDT), wrote:

This weed, which we call "The Tumor" (in your best Arnold
Schwartzenager voice) is drivng us nuts. It comes on super fast,
grows super fast and returns after we pull it out. Its got prickly
edges. See phot link below.

Is there a chemical based weed killer that can take this out? Preen
did nothing to it. This weed just laughed at Preen.

http://ucemergencymedicineorg.siteprotect.net/weed.jpg

Look like wild lettuce to me. Lactuca something or other. It spreads
by seed I think, so I doubt it's coming back - just new plants.
Personally I like the plant - it grows tall with yellow flowers that
open in the morning. If you pull it out, roots and all (easiest after
a rain) and don't let plants go to seed you won't have it next year.

A chemical based weed killer is likely to take out all kinds of things
besides the plant you don't want. Some of those things may be
beneficial to you without your knowing.

Best to deal with specific problems specificly, imo.

hth,

Kate