Bottom left image: Harry Rose from South West Rocks, Australia, Poa annua plant2 (7398665598), crop from Plantopedia, CC BY 2.0
For anyone who wants a nice, even lawn in their garden, Poa annua, the annual meadow grass, is a sheer horror. To a certain extent, it fragments the lawn by forming several islands with the weeds or weeds. Since individual grass stalks can also grow up to 30 centimeters high, the aesthetic perception usually suffers a lot. This unloved pest can only be fought by ripping it out or digging it out. Unfortunately, organic sprays do not help.
Recognize
The perfidious thing about this weed is that it immediately catches your eye. The grasses and tussocks are much lighter in color than the lawn. Instead of blending into the lush green, the sometimes almost white meadow grass stands out clearly. Of course, there can no longer be any talk of an even, closed surface. In addition, the individual stems can reach a length of up to 30 centimeters. In most cases, the lawn appears very shaggy and unkempt. Specifically, the intruder can be recognized by the following characteristics:
- very light green coloring of the entire plant
- Formation of an eyrie or nest
- very short creepers
- blooms for almost the entire growing season
If all of these characteristics are present, there is clearly an infestation with Poa annua, which you should combat immediately. Alternatively, however, Poa trivialis or a type of millet may have crept in. There are great similarities, however, as a rule, they do not share the above features at the same time.
Tip: Poa trivialis can be recognized, among other things, by the fact that it does not bloom throughout the growing season, but only in June and July.
harmful effect
Weeds are also plants, you don't always have to fight them, but it's a little different with Poa annua. It's not just the visual impression that suffers. Rather, this type of bluegrass can spread so massively that sooner or later the entire lawn suffers. If you do not take early action to prevent the spread, the only thing that can help is total sanitation. These are the concrete dangers that emanate from the weed:
- it robs the desired lawn of the necessary nutrients
- forms a large number of seeds that can be easily distributed
- has a high susceptibility to root rot and snow mold, which can be transferred to the lawn
- develops conspicuous yellow and brown colors when dry
- leaves little room for the desired weed to develop
- immediately colonizes every free area in the lawn
Bluegrass tends to become dominant very quickly. If you let it, the matter with the green lawn is often completely settled after two to three years. Combat is therefore urgently needed.
Rasbak, Poa annua, crop from Plantopedia, CC BY-SA 3.0
Fight Poa annua
Weeds are best fought with an organic spray or with a household remedy that should not necessarily be based on chemicals. Unfortunately, neither works with bluegrass. There is neither an organic spray nor a home remedy that could actually kill the plant.
Notice: A total chemical herbicide would of course destroy the plant. However, spraying this agent would also damage the rest of the lawn and other plants.
In order to be able to combat this type of bluegrass effectively, it only helps to uproot or dig up each individual plant together with the root. It is important to immediately fill up the resulting hole with soil and sow the free space with grass again. The weed itself should definitely be disposed of in the closed dustbin to avoid seed flight and thus resettlement.
prevention
Cutting out the individual plants is a laborious affair. It is much easier to prevent an infestation in the first place with a few preventive measures. The most important measure is regular mowing of the lawn. Mowing is something of a reliable household remedy. You should pay particular attention to the following points:
- Always mow the lawn very short
- start mowing very early in the year
- Mow often and regularly depending on the weather
The purpose of mowing is to prevent any meadow grass that may be present in the lawn from forming seeds. The plant itself can be combated preventively by scarifying the lawn at least once a year. In addition, existing gaps should be closed as quickly as possible by overseeding.
Poa annua can also be kept in check by watering. The weed likes it wet, while it does not cope well with dry conditions. The lawn should therefore only be watered very sparingly. Under no circumstances should the lawn sprinkler run for several hours a day. A vigorous watering every two weeks makes sense. Exception: If the heat is strong and lasts longer, watering has to be done more often.