Poa annua, also known as annual bluegrass, is a common weed that can be found in turf areas. While it may look harmless, Poa annua can quickly become a problem, as it can crowd out desirable grass species and create an uneven surface. Controlling Poa annua requires a combination of proper turf care practices, manual removal, herbicides, and preventative measures. In this article, we will discuss identifying Poa annua, its life cycle, and the various strategies for controlling Poa annua in turf areas.
Identification & Life Cycle
Identification is key, as early intervention can prevent the grass from becoming established. It has bright green leaves that are thin and flat, and have a boat-like shape at the tip. The weed is known for forming small groups or clumps and produces flowers during the fall and winter season. When it flowers, it has small spiky clusters of whitish-tan flowers, which are located at the top of the grass stem. These clusters of flowers are known as seed heads. The plant dies off in the spring as temperatures rise, but the seeds can remain on the soil surface for years before germinating again.
Controlling poa annua
Poa annua is considered one of the most difficult turf weeds to control. However, there are effective methods for managing and controlling Poa annua.
1. Proper turf care practices:
One of the best ways to prevent the establishment of Poa annua is to maintain healthy turfgrass. This includes regular mowing, watering, and fertilization to promote a thick, healthy turf. Aerate and dethatch your lawn regularly to keep the soil loose and allow water and nutrients to reach the roots of the desired turf species. This can help prevent the establishment of Poa annua by creating a dense root system that reduces bare spots and weed invasion.
2. Manual removal:
For small infestations, manual removal can be effective. This involves pulling out the Poa annua by hand, making sure to remove as much of the root system as possible. It is important to do this before the plant produces seeds, as the seeds can remain dormant in the soil for years and sprout later. This may prove to be labor intensive in certain situations.
Pre-emergents and post-emergents can be effective in controlling Poa annua. Yet, they should be used with caution.
Post-emergent herbicides on Poa annua should be applied when the grass is actively growing. Care should be taken to avoid damage to non-target species.
Pre-emergents can have an effective control on preventing the seeds from germinating. Timing the pre-emergent application is very crucial. Apply the pre-emergent before soil temperatures reach 70 degrees. Be aware that the pre-emergent may effect the germination of overseeded turf as well.
Currently there is no herbicide that strictly targets Poa annua. Using both pre-emergent and post-emergent may take several applications for an effective control.
4. Preventative measures:
Prevention is key to managing Poa annua. Avoid overwatering your lawn, as this can create a damp environment that is conducive to the growth of Poa annua. Additionally, avoid over-fertilizing your lawn, as this can promote the growth of Poa annua and other weeds.