Quack and Crabgrass

Quackgrass and Crabgrass are probably the two most common lawn weeds.  Crabgrass and Quackgrass both love hot dry conditions and spread rapidly when those same conditions weaken your turf grass.

The crabgrass grows from seed left behind by last year’s plants and die back in the fall.  The plant is flat and spreads across the soil surface.  Crabgrass first appears as small plants in early spring. If you apply crabgrass pre-emergent in very early spring you should have little or no problem with crabgrass.  The pre-emergent prevents the crabgrass seed from germinating.  The pre-emergent is commonly combined with fertilizer and easily available every spring.  Since crabgrass will germinate when the soil temperature has been consistently 50 degrees for about 5 days, it is important to apply early.  Do keep in mind that it takes the soil a lot longer to warm up than the air.  Nights are substantially cooler than warm spring days, so that also slows down the warming of the soil.  Although it is difficult to determine your soil temperature, you can safely apply the crabgrass pre-emergent ahead of time.  When you see the first dandelion bloom, it is time to apply the pre-emergent.

If you did not apply a crabgrass pre-emergent, or applied it too late, you can pull the plants out.  They are a shallow rooted plant so they pull out fairly easily.  But to make quick and complete work of the task, get a good hold at the base of the leaf stems, grasping all the leaves from a single plant at once.  Then just pull straight up.  It you pull when the soil is moist, not long after a rain, the plant will pull out quite easily.  If crabgrass is not removed when young, the plant will spread rapidly across the lawn surface as it matures, choking out you turf grass.  When fully mature, long branched stems with thousands of seeds form.  All those seeds will be waiting to sprout next spring.

Quackgrass is a perennial lawn weed that is very difficult to control.  It has an extensive and deep root system that is very difficult to pull.  It grows tall quickly then spreads out.  Underground rhizomes spread rapidly and send up many new plants.  If allowed to mature it will also produce seeds on upright stems.  Unfortunately, standard lawn weed controls have no effect on quackgrass.  A non-selective weed control such as round-up will kill quackgrass, but it will also kill any grass or plant it comes in contact with.  If the problem is severe apply on a very calm day ,trying a much as possible to limit the spray to the quackgrass plants.  You may wind up doing a little seeding in the bare spots.  If you catch quack grass when it is still young, you can try pulling it out.  Be sure your soil is good and moist after a soaking rain to help remove as much root as possible.  Bits of roots and underground runners may produce new plants, so keep an eye out for them and pull as soon as possible.

Once you have quackgrass in the lawn, it is very difficult to eradicate.  Seeds will drop for next year and rhizomes will be left in the soil to shoot up new plants.  Keeping your lawn healthy and thick will help keep quackgrass crowded out of the majority of the lawn.  But of course the real problem areas area along the driveway and curb where the grass is stressed, dry, and constantly weakened by foot traffic.

If you can get crabgrass and quackgrass under control, keeping it that way will only require minimal attention.