Question
I have a rental property in Discovery Bay, California, with a 90/10 mix lawn.  It has been overcome by about 75% bentgrass which looks terrible.  It gets heat stressed easily, or goes dormant in winter much worse than balance of lawn...yuk!

It will become vacant again in March 09, and we'll be faced with the need for curb appeal.  I've received an estimate to replace the entire 1600 sq. ft. lawn area with new sod at $2400.00, as the only method to truly eradicate bentgrass.  (After first having sprayed the entire lawn with roundup, and waiting for it all to die out)

What can you tell me about bentgrass?  Is there no other method to eradicate it selectively with chemicals?  Are we really talking about a "replacement only" solution?

Help please!

Answer
Bentgrass -- 'Agrostis palustris' in my neck of the Woods, 'Agrostis densiflora' in yours -- is a noxious Weed that spreads all over coastal California and Oregon:

calphotos.berkeley.edu/cgi/img_query?query_src=photos_index&enlarge=0000+0000+0305+0264


The California DOT deals with Weeds like this year round.  They have posted some of their controls, and some that they have rejected, and the general results of each:

teamarundo.org/control_manage/docs/alt_veg_control_2003.pdf

See the 'Executive Summary.'  Flaming and Mowing are two very effective methods of controlling the most pervasive Weeds.  They point out that 'Flaming... controlled vegetation very effectively if applied to small, newly developed Weeds.  Under wet, damp conditions, the heat from the flame was conducted down the leaves of the plant below the Soil, where further destruction occurred.  One or two applications controlled vegetation, but the cost of gas, labor and the application speed would prohibit the use of this technique on a large scale.'

On a small scale, though, it would work.

They also make use of Corn Gluten Meal and numerous other non-toxic Weedkillers, both pre- and post-emergent.  You Californians are lightyears ahead of the rest of the country when you have the state doing cutting edge Weed control.  Some of these products even have food grade ratings.  That's incredible.

But there is another side to this problem, and that's your Lawn.  Grown well, the right kind of Grass will overcome most Weeds without you lifting a finger except to mow it.  What kind of Grass were you growing that caved in so easily?  You have Full Sun?  How's the Soil?

In addition, given that your goal here is undoubtedly to minimize cost and labor, I would like to strongly recommend that you consider a vigorous groundcover instead of Grass.  It would not need mowing or watering; it would be environmentally friendly; poor Soil would not be a factor; and you would not lose any sleep over Bentgrass.  Any ideas?

THE LONG ISLAND GARDENER