Controlling Annual Bluegrass: How to Get Rid of Poa Annua

We all know that weeds are a pain. And while we try to keep our lawns and gardens as weed-free as possible, sometimes they can creep in and take over. Annual Bluegrass, or Poa Annua as it is formally known, is one such weed. It can be hard to control, and it grows quickly and spreads easily throughout your lawn or garden.

In this blog post we’ll go over how to identify annual bluegrass as well as some tips on how to treat the plant with herbicides and other treatments. You may even find some helpful hints about protecting your plants from them in the future! Keep reading below for more information about controlling annual bluegrass.

What Annual Bluegrass Is

Annual bluegrass is one of the most common weeds found anywhere and everywhere in the United States, as well as many other countries around the world. In fact, it is so common that many homeowners and business owners use it for grass. The famous Oakmont Country Club in Pennsylvania, as well as other golf clubs around the country, use annual bluegrass on their putting greens.

It is officially called Poa Annua, and has been known as Annual Meadow Grass as well, but Annual Bluegrass is its most common moniker. It is an annual weed, as you can infer from its name, and it is a low-growing turfgrass that grows in temperate climates.

How and Where It Grows

As Annual Bluegrass is an annual weed, it grows for a single year, casts seeds around it throughout the meadow or yard that it is in, and then dies. It germinates in the late summer and autumn, after soil temperatures drop below 70 degrees F (21 C), and continues to germinate all throughout the winter. It is very fast and effective at seeding, so a single small plant can produce up to 100 seeds in only two months.

This weed has relatively shallow roots and grows quickly which makes it hard to fully kill. It spreads quickly and thrives in moist conditions, like places with frequent rainfall or lots of irrigation. In the high heat of summer it usually withers and dies, leaving unsightly brown spots in your lawn.

What It Looks Like

You most likely have seen Poa Annua growing all around you your whole life; it is incredibly common and found in almost every city and street in the USA. It isn’t a particularly high-growing weed, usually growing about 6-10 inches in height, but it will certainly stand out above your grass. It tends to grow in clumps; the grassy stem parts are usually slightly flattened, a bit boxy in shape, and rough and serrated at the edges.

At the top of these stems there are tassled, flowery pods that grow 1-2 inches in length and are a more pale green. If there is a large infestation of Annual Bluegrass, all of the tops of the plants will seemingly blend together into a white-green feathery cloud that seems to lay over the grass.

How To Eliminate Bluegrass From Your Lawn

Poa Annua is a tricky weed to kill and remove completely from your lawn or garden because it is so hardy and spreads so quickly.

As Annual Bluegrass is an annual weed, it only lives for one year and therefore does not have a large root system that stores resources. Of course, if you allow the plant to take over the roots of the grass plants in your yard, it will start to dominate.

First you need to identify where the weed is growing if you don’t want it spreading throughout your entire lawn or garden. You can use both organic and chemical means of removal, or take a combination of the two to fully get rid of this weed.

Using Organic Ways

The first thing to do when dealing with Annual Bluegrass is to pull up any plants that are starting to dominate your lawn and remove them. This is the simplest and most organic way of dealing with Annual Bluegrass, but it may not be enough. For a stronger attack against Poa Annua, you can also use additional organic techniques to kill the weeds and keep them from coming back for good.

You can get an organic herbicide spray made from vinegar, oil soap and dish soap to help kill all of the weeds in your lawn. This spray is safe for animals and will not harm any other plants that you may be growing. Boiling water can be used to kill weeds in the same way, so if you want an organic alternative, try pouring boiling water wherever you see dead or dying grass. Do this a few times and it should kill the weed without harming your grass.

You can also try fertilizing your lawn with corn gluten, which acts as a fertilizer and is also organic. Using corn gluten to fertilize will not only keep Annual Bluegrass from growing, but it will also prevent other weeds from growing as well because corn gluten prevents root formation. However, it will not prevent the seeds from germinating.

Using Chemicals Ways

Chemical weed killers can be purchased from a local home and garden store, but you will want to make sure you use the right chemicals on your lawn because you do not want to do more harm than good. The best chemical weed killer for Annual Bluegrass is a pre-emergent herbicide, which is made of certain fertilizers that will not only kill the weed, but prevent it from coming back for one full year.

The pre-emergent herbicide can be used with any fertilizer and will help make sure your grass stays healthy throughout the season. It works by preventing new weeds from sprouting up, and stops the seed germination process before it begins.

Apply the product during early fall so that you have time for it to take effect before winter arrives, and early spring when the plant is growing actively. However, while a pre-emergent herbicide will effectively control Annual Bluegrass for the year, Poa Annua is a tough weed and can withstand many years of not germinating.

You will need to continue using this weed killer for multiple years to ensure you kill all of the Poa Annua seeds so that it won’t ever come back.

How to Prevent Bluegrass From Growing

Annual Bluegrass is an annual weed, so the primary way to prevent infestations is to stop the seeds from growing in the first place. As they say, prevention is the best cure. There are few tips you can use to help prevent Poa Annua from getting a foothold in your lawn.

Keep your grass short: Annual Bluegrass is more likely to grow if your lawn is long and shaggy. Keeping your grass cut at about 2 inches will make it less appealing for Poa annua seeds (and other weeds) to grow there.

Because Annual Bluegrass likes moist, compact soil conditions, you should make sure your lawn is healthy, dry, and well aerated. Cultivating your soil regularly will help to reduce the amount of weeds in your yard by aerating deep into the soil and allowing sunlight to reach grass seed and help it to grow.

A dense turf of healthy grass and plants is a great way to stop Poa Annua as well, because there is not much room for any other plants to grow. If you have a lot of weeds in your garden, either plant more grass or cultivate the soil so that it becomes less weed-friendly.

That’s All

Poa annua is a weed that grows everywhere: you can find it in your lawn, garden, local sports fields, anywhere grass is found. And it can be very difficult to control.

But, as you can see from the information in this blog post, there are a few different ways to control and prevent Annual bluegrass. You should be able to find one that best fits your needs and preferences for getting rid of annual bluegrass from your lawn. You can also learn some preventative measures that will keep annual bluegrass away in future seasons. If you’re looking for more help with controlling annual bluegrass or want some tips on how to prevent it from coming back next year, make sure to contact us!

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