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Moe DeLoughan · 18-05-2016, 02:26 PM posted to rec.gardens

On 5/17/2016 10:03 PM, wrote:
Hi.

I have a patch of very agressive grass spreading into the rest of
my lawn. It is rather broad bladed and maybe a bit lighter in color
than most grasses. A specific quality is that it has a strange
pungent smell when mowed, almost like hot plastic. I have heavily
applied a crabgrass targeting dry weed 'n feed type of product by
Fertilome but it has had no visible effect. Can anyone tell me what
this stuff might be?

If you live in the US, you probably have a County Extension Office,
and the County Extension Agent can identify the grass for you. Another
option is to find a knowledgeable person at a local farm and garden
store, but that can be hit or miss. It is important to have the plant
accurately identified, because you won't know what will work on it
until you know what it is. Crabgrass preventer (which is what is in
your combo packages with fertilizer) is a pre-emergent herbicide that
is applied earlier in the growing season before annual grass seeds
have begun to sprout. It will then work by killing the seeds as they
sprout. If your grassy weed is a perennial, the crabgrass preventer
will have exactly zero effect upon it.

Broadly speaking, the only effective control for perennial grassy
weeds is a non-specific herbicide such as Roundup, which kills
everything it touches. It is difficult to develop an herbicide that
can distinguish between good perennial grasses (your lawn grasses:
bluegrasses, fine fescues and hybrid perennials ryes) and bad
perennial grasses (tall fescues, quackgrass, etc.).

But again, your best bet is to take a complete sample of the weed
(stems, blades, and roots) to a local expert for identification and
advice as to the best approach for dealing with it.