Monday, July 29, 2013

What Does Crabgrass Look Like?

Late July has welcomed the growth and development of mature crabgrass once again on the lawns of Northern Illinois.  This annual ritual begins in late spring when the soil temps get above 60 degrees allowing the seed from last year's crop to germinate.  The plant begins a slow development process that really doesn't fully blossom until once the temps get above the 90 degree mark for several days in a row.  This usually occurs late July when the lack of moisture also assists in the thinning of desirable grasses leaving plenty of room for the crabgrass to fully expand.   This has happened every summer for thousands of years and will continue to do so for as long as anyone reading this will ever survive.  There are a lot of mis-identifications when it comes to spotting crabgrass so I would like to discuss a few identifiable characteristics .

 Crabgrass in a thin area of turf just off of a curb

Crabgrass is most commonly found along driveways, curbs, sidewalks and anywhere that soil temperatures can escalate quickly in the summer months.  It can also be found in the middle of low-maintained turf areas especially when the turf is cut very short.  Crabgrass spreads out more horizontally on the ground which is why these areas are much more inviting for the plant.  It is an annual grass that puts out a seed head every summer for next year's growth.  These pictures show the spreading nature of the grass from its center rather than growing upright like most other grasses.

Crabgrass is most commonly confused with tall fescue in the Northern Illinois area.  Tall fescue grows naturally in many lawns because it is a native wild growing plant in the area as well as the fact that it is used in a lot of cheap grass seed blends available in the Midwest.  It is a perennial grass that grows every year in the same spot.  It often stays greener longer in summer but browns out early in the fall and spring.  It is actually better suited for the temperature ranges found locally however the rough leaf blade characteristic makes it much less appealing to most homeowners.

Tall fescue growing in middle of bluegrass lawn ( this is not crabgrass!).

The easiest way to tell the difference between the two grasses is its height.  Tall fescue grows significantly taller than the surrounding bluegrass, however crabgrass grows longer horizontally than it does vertically.  The more scientific approach to distinguishing the two is the leaf.  Crabgrass has a smooth leaf blade while tall fescue has a ribbed and course leaf blade texture.  The leaf of a crabgrass plant also contains tiny hairs and has a deep low collar.  The tall fescue has a broad collar similar to a man's shirt and no small hairs.  

Crabgrass with no collar and tiny hairs

 Tall fescue with broad shirt-like collar and no hairs.  

Crabgrass can be easily treated when properly identified, while tall fescue is usually left to grow in most lawns.  Unfortunately tall fescue is usually mis-identified as crabgrass by most homeowners leaving them frustrated that their pre-emergent crabgrass product did not work properly.  Properly identifying crabgrass and tall fescue can lead you to the right solutions faster when treating your lawn.  If you have any concern wether crabgrass or tall fescue is taking over your lawn call the professionals at Lawn Doctor today.

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