Poa Annua – Annual Bluegrass

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Poa annua, otherwise known as annual bluegrass, is an annual grass that usually spreads by seeds. It has bright green colored leaves with a fine texture and a tufted look. It grows in a variety of conditions but moist and compacted soil suit the weed the best. Well irrigated turfs and a good rainfall can be really inviting to this weed. It also thrives in a range of light conditions from partial shade to full sun. One of the problems with this weed is the fact that it can produce seeds throughout its lifecycle with the majority of the seeds appearing early in the spring. Once your lawn is infected with even a few of these plants, the spread can be really rapid as mowing, birds and foot traffic all can lead to spreading the seeds far and wide throughout your lawn. If left unattended, this weed can completely take over your lawn in a matter of weeks.

Goals of Management

Weeds can be such an eyesore in lawns. Not only can these hideous weeds mar the beauty of your lawn, they can be a real threat to the overall health of the grass as well. A proper weed control program is pivotal in maintaining a healthy and lush lawn. Weeds can be very pesky, but surprisingly resilient. If you do not take the proper care, well, they do spread like weeds and soon take over your precious green patch of heaven! This is why many homeowners turn to a lawn service to take care of this problem.

A complete elimination of the annual bluegrass from your lawn can be very challenging after a large infestation.

How to Manage Poa Annua?

As the saying goes, prevention is better than cure. One of the best ways to control the spread of this aggressive weed is to eliminate the spread of the plant to uninfected areas. No single method is successful in eliminating bluegrass from lawns. Instead, a series of general practices can be implemented to control the spread along with some measures to control it. Let’s look into how can this problem be tackled with a multi-pronged attack:

  • As a rule of thumb, always make sure that the density of grass in your lawn is high. Less dense and patchy lawns expose fertile land for the weeds to grow.
  • Watering is essential, but make sure you are not overwatering your lawns. Overwatering your turf will make the grass vulnerable for a bluegrass invasion.
  • Avoid aerating the lawn during the peak of bluegrass germination period. This will aid in spreading the seeds and magnifying the problem.
  • If any solitary bluegrass growths are spotted in your lawn take them out immediately before they begin to seed. Isolate the areas where the infestation has already occurred and make sure that you are not spreading seeds from these areas to the uninfected areas.
  • Manual weeding is a sound defense against this weed, although, it can be labor intensive and would require frequent attention.
  • Some herbicides have been quite successful in limiting the germination of the annual bluegrass and can be applied before the seeds of the weed germinate. However, these don’t have any impact on the germinated plants. The best time to apply these pre-emergent herbicides is early summer or early fall when the soil temperatures are below 70F.
  • Always remember the fact that if you plan on using herbicides, always remember to get it done by a lawn service pro.
  • In some cases, Poa Annua has been known to exhibit resistance to these herbicides due to repeated and overuse. Always limit the usage of herbicides and employ them as a final solution if nothing else works.
  • In the worst-case scenario, if the Poa Annua infestation is too severe, it might be best to start fresh by completely doing a complete kill-off of the turf. You can apply a nonspecific herbicide such as glyphosate that works for a few months and then re-seed or lay new sod.