Annual bluegrass (Poa annua) Flower, Leaf, Care, Uses

Moisture-loving, keep the soil moist but do not let water accumulate.

Fertilization

Fertilization once in spring.

Soil

Sand, Clay, Loam, Chalky, Acidic, Neutral, Alkaline

Sunlight

Full sun, Partial sun

Hardiness Zones

Grasses, sedges and allies

4 to 10

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Annual bluegrass

Water

Twice per week

Sunlight

Full sun

Hardiness Zones

4 to 10

Planting Time

Spring

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Questions About Annual bluegrass

Watering

Pruning

Sunlight

Temperature

What should I do if I water my Annual bluegrass too much or too little?

Overwatered Annual bluegrass

If your grass is turning yellow or pale green, it may be getting too much water. Although Annual bluegrass is tolerant of almost any soil type (it is not sensitive to pH, and can be in sandy, loamy, or clay soil types), it doesn’t do well in soil that doesn’t drain well. Avoid planting this grass in marshy areas or where the ground feels spongy. If you irrigate your lawn, err on the side of too little water vs too much, since Annual bluegrass does best if it’s allowed to dry out before being watered again.

Wet soil can allow fungus to grow, or create a favorable habitat for insect pests and weeds. Of course you can’t control how much rain falls on your Zoysia grass, and the occasional heavy rainfall is unlikely to cause problems for this resilient plant. However, long-term overwatering can cause the plant to suffer and even die off.

Underwatered Annual bluegrass

One of the advantages of growing Annual bluegrass is that it can survive without much water since it has adaptations that help it to conserve water. This grass has a deep root system, meaning it can use groundwater if it hasn’t been watered in a while. In drought conditions, this grass will turn yellow and get crispy, but it can recover once the dry spell is over. The ability to recover from a variety of conditions is one of the many reasons that Annual bluegrass is such a popular grass.

How to water Annual bluegrass?

In most places where grasses are used in landscaping, there will be sufficient rainfall to keep it looking good without supplemental irrigation or watering. However, if it is planted in a very dry climate or there is a lengthy drought, Annual bluegrass may die out if it isn’t watered. During the winter months, this grass goes dormant and may appear to be dead, but it still needs moisture to keep from becoming fully dehydrated. It regrows as weather warms up in the spring.

A good rule of thumb for watering Annual bluegrass is that it does best with about an inch of water every 1 week. A thorough drenching in a short period of time is better than a slow and steady drip, as it leads to a stronger, deeper root system.

Freshly planted grass has more specific requirements for watering. After planting, the young grass needs to be kept moist for the first 3 to 4 weeks until it has a chance to establish itself. The best time of year to plant Annual bluegrass is in the late spring to early summer, when there tends to be plenty of rainfall anyway. However, if your area experiences a dry spell after you’ve recently planted grass in your lawn, it is a good idea to cover the grass to prevent water evaporating or to water the lawn to keep soil moist.

What should I consider when watering my Annual bluegrass?

The environmental conditions, soil type, and amount of drainage will affect how often Annual bluegrass needs to be watered. If your lawn has sandy soil that doesn’t retain much moisture, you may need to irrigate to keep this grass looking its best. Clay soils that drain slowly and hold a lot of water are less likely to need additional water, but can be bad for Annual bluegrass as this grass is sensitive to too much water around its roots.

Is pruning necessary for my Annual bluegrass?

Annual bluegrass is a kind of annual plant so it doesn't need much pruning. You only need to cut off and clean the diseased, yellow or dropped leaves and stems during its growing period. This will help your Annual bluegrass to stay away from pathogens infection.

How do I prune my Annual bluegrass?

During the growth of the plant, yellowing, drying and spotted leaves are produced, and these spotted and discolored leaves need to be trimmed off. If the whole piece of leave is discolored or infected, you will need to cut it off completely. In other situations, you will only need to cut off the discolored or infected part on certain leaves. Annual bluegrass above the ground will die and dry up in the winter, and the dead plants need to be cleaned up.

Are there any cautions I should be careful with when pruning my Annual bluegrass?

Annual bluegrass leaves are delicate, so take care not to score or bruise them. Unless the leaves are withered or heavily discolored, do not prune the leaves from the lowermost branches unless they’re damaged. They typically grow the largest, so they supply the plant with critical energy to keep it growing right. Please prevent the wounds from water after pruning until they are fully recovered. Remember always sterilize the tools before pruning. When the pruning is finished, please throw all the waste leaves and stems into the trashbins to avoid diseases and bugs.

Are there any tips for pruning my Annual bluegrass?

Sterilize all the tools before pruning; unclean tools will pass pathogens to the plant through wounds;
Prune on sunny days because the new cuts will be infected by pathogens if they're distained by rain or water.
Throw all the waste leaves and stems into trashbins, they will easily rot and attract diseases and bugs

When should/shouldn't I prune my Annual bluegrass?

Expect to prune your Annual bluegrass every week if it’s growing well or every two weeks if it grows slowly. It is always good to prune it on sunny days because if you prune it on rainy days, the rainwater will distain the cuts and cause the whole plant to be infected.

What should I look for when pruning my Annual bluegrass in different seasons?

Because Annual bluegrass is an annual plant, the pruning should take place basically during the seasons that the plant grows rapidly. During the growth of the plant, yellowing, drying and spotted leaves are produced, and these spotted and discolored leaves need to be trimmed off.

How much sunlight should Annual bluegrass get per day to grow healthily?

You must expose the plants to at least 6 to 8 hours of sunlight daily. They prefer more exposure to the morning light, especially in the summer. The Annual bluegrass needs full sun and more sunlight that it can get. The more light these species get, the more they can manufacture food, produce beautiful blooms, and survive.

What type of sunlight does Annual bluegrass need?

The Annual bluegrass grows best under full sunlight. It's best not to crowd them together so they can get exposure to the sun evenly. The leaves shouldn't be starved with sunlight. If planted in pots, try to expose the herbaceous flowers in windows with direct sun and ensure they receive full sunlight regardless of the months.

They don't tend to do well in partial or filtered light as this will not produce strong stems and healthy flowers. It's best if the Annual bluegrass is always exposed to the sun.

Can sunlight hurt plants? How to protect Annual bluegrass from sun and heat damage?

When the temperature rises above 90℉(32℃), the Annual bluegrass can get damaged by extreme temperatures, especially if they are exposed to many hours of sun. It's always ideal for providing some shade from the light in the afternoon in the summer. It's always important to keep in mind that the sunlight in the summer is stronger than the one in the winter. Sunlight exposure is also 50% longer in the summer than in the winter.

If the Annual bluegrass is too stressed with sunlight, you might want to keep them fully hydrated. Water them when the top of the soil is about 2 inches dry, and move the plants indoors if it's too hot outside. This is the case if they are planted in containers.

It can be normal for the plant leaves to wilt during the day. Generally, they can recover at night. However, when you notice that the Annual bluegrass is still drooping, this means that the plant is losing water fast, and you need to water them.

Should I protect Annual bluegrass from sun exposure?

The Annual bluegrass does not need any protection from the sun. In fact, they love the sun, and some species are heliotropic. Plant them in south-facing gardens whenever possible so they can be exposed from morning to afternoon. While the sun can benefit them, some may experience a sunburn. You might offer protection from the afternoon and midday sun through a shade of a tree or a wall.

Growing the Annual bluegrass in shady areas is impossible because the larger flowers would require a lot of energy to grow and produce. Always provide the lighting conditions and set them in an area with full sun for best results.

What will happen if Annual bluegrass gets inadequate sunlight?

When the Annual bluegrass does not get adequate sunlight, or they are not placed in full sun locations, it's worth noting that the photosynthetic process will slow down. A lack of sunlight will cause the stems to become more leggy since they become thin and long since they tend to seek too much sunlight. They will not bloom and produce seeds in the shade.

Inadequate sunlight will also mean that the older leaves can die, the color of the new ones is lighter than the old foliage, and the new growth is smaller than the last ones.

The Annual bluegrass indeed loves the sun so much. However, they can wilt when exposed to excessive heat and ultraviolet light during the extreme summer months, so be careful. You might want to cover them with a net that has a green shade, especially in the summer, to prevent the leaves and the flowers from scorching. When they are indoors, reduce the heat with the help of a fan.

Does Annual bluegrass need special care about sunlight during its different growth stages?

When the Annual bluegrass is growing, they need more light than their mature counterparts. The younger ones should receive adequate light, but they might not be prepared for sudden full sunlight, especially if they are grown in a nursery. They can be more sensitive to the summer sun, so the lighting should be gradual and slow.

How much light does Annual bluegrass need for photosynthesis?

During summer or late spring, the Annual bluegrass needs 6 to 8 hours of direct light every single day. This is whether they are planted outdoors. If the Annual bluegrass is planted in pots or you're growing them in the winter, they need direct fluorescent lights that help them grow better. Make sure to place them in an indoor area where they are facing south or east so they can have enough sunlight for photosynthesis.

Are there any cautions or tips for sunlight and Annual bluegrass?

When transplanting the plants, they should not be exposed to sudden sunlight. Give the Annual bluegrass to grow and mature before transplanting outside. Some species of herbaceous plants can grow taller and might cast a shade on other young plants. Allow between 80 to 100 days of growing season before planting another batch to ensure that every plant receives more than enough sunlight for at least 6 hours a day.

Make sure that the Annual bluegrass receives the best light possible, especially if it's planted in a nursery. These are sun-loving plants, but too much sunlight with a very hot temperature is also detrimental to their growth. Indoor lights should be replaced with natural sunlight as much as possible since these species crave this every day.

What is the optimal temperature for Annual bluegrass?

The best temperature for Annual bluegrass depends on the time of year. There are two primary seasons to discuss for temperature: the growing season, and the dormancy season. During the growing season, once Annual bluegrass has begun to sprout, the ideal temperature range should be anywhere from 65~80℉(18~27℃). Any colder than 15℉(-10℃), and the plant will suffer; its leaves may brown and wilt, but if this is a short cold snap, then Annual bluegrass may be able to survive with some help.

During the warmer parts of the year, Annual bluegrass will need to be similarly protected from temperatures that are too high. 95-105℉ (35-40℃) is the top of this plant’s temperature range, and anything above that will compromise the integrity of the foliage and blooms of Annual bluegrass. Hotter temperatures can cause wilting, drooping, and even sunburn on the leaves, which can be difficult for Annual bluegrass to recover from. There are quite a few ways to combat this issue that are quick and easy!

Temperature requirements for first year or seedling Annual bluegrass

If this is the first year of your Annual bluegrass outside as a new plant, then it may need a little extra tending during the coldest months of the year. Not only can frost more severely damage a first-year Annual bluegrass, but it can also prevent it from growing back as a healthy plant come spring. This plant needs to be kept at 40℉(5℃) or above when they’re not yet established, which can be done either by bringing your Annual bluegrass inside for a month or two, or putting up mulch or fabric barriers that protect from frost damage.

It’s also a good idea to plant Annual bluegrass in a shadier spot during the first year or two, as smaller and weaker plants have a more difficult time maintaining their own temperatures in the heat. First-year Annual bluegrass should receive no more than five hours of direct sunlight per day, particularly if the ambient daytime temperature gets above 80℉(27℃). Shadecloth and frequent watering or misting are the keys to summer heat control.

How can I protect Annual bluegrass from extreme temperatures?

If cold temperatures (below 15℉(-10℃)) do occur during the growing season, there are a few measures you can take to help protect Annual bluegrass from frost or cold damage. If you’re growing Annual bluegrass in a container, then the container can simply be brought inside in bright, indirect light until the temperatures rise up over the lower threshold again. Another option that’s better suited for ground-planted Annual bluegrass is to use mulch or horticultural fabric to create an insulated barrier around the plant, which will protect the plant from frost and cold wind.

For temperatures that are hotter than 80℉(27℃) in the shade during the day, be careful to only expose Annual bluegrass to six hours or less of sunlight per day, preferably in the morning hours. Putting up shade cloth, or a fine plastic mesh, can help reduce the amount of direct sunlight that hits the plant during the hottest parts of the day. You can also install a misting system that allows for a slow release of cooling mist around the base of the plant during the day to lower ground temperatures.

Dormant season temperature recommendations for Annual bluegrass

During the cold winter months, Annual bluegrass needs a certain measure of cold in order to stay in dormancy until it’s time to sprout. Sprouting too early, that is before the danger of the last frost has passed, can be fatal to Annual bluegrass, especially if it’s already had a head start when the frost hits. Winter temperatures should ideally stay below 32℉(0℃), but if they get up to 40℉(5℃), everything will be just fine.

An unexpected warm spell during the cold months, which can happen in more temperate climates like woodland rainforests, can trigger a premature sprout from Annual bluegrass. In this case, if there’s still imminent danger of frost, you may want to try covering it with clear plastic on stakes so that the cold has less of a chance of damaging the new sprout. This setup can be removed when the danger of frost has passed. Occasionally, Annual bluegrass will be able to resprout at the correct time without any help, but this method increases the chances of a successful second sprouting.

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Common Pests & Diseases

Common issues for Annual bluegrass based on 10 million real cases

Aged yellow and dry

Natural aging can cause leaves to turn yellow and dry out.

Solutions: If the yellowing and drying of leaves and flowers is a natural progression due to age, nothing can be done to slow or stop the process. Once hormones within the plant begin the process of senescence, it’s irreversible.

Underwatering

Leaves may wilt for a variety of reasons.

Solutions: The easiest (and most obvious) way to address underwatering is to fully hydrate the plant. However, this must be done carefully. A common mistake that many gardeners make is to douse their underwatered plants with water. This can overwhelm the roots of the plant and shock its system, something that can be even more damaging than the lack of water to begin with. Instead, water thoroughly and slowly, taking breaks to let the water slowly saturate through the soil to get to the roots. Use room temperature water, as cold water might be too much of a shock. In the future, shorten the time between waterings. A good rule of thumb is to check the soil around each plant daily. If it’s dry to at least two inches down, it’s time to water. If a container plant is repeatedly drying out very quickly, repotting into a slower-draining container might be a good idea, too.

Brown spot

This infection can cause brown spots or patches to appear on the plant.

Solutions: In minor cases of brown spot, there isn’t any need to treat the disease. However, if much of the foliage is affected and defoliation occurs, the plant will benefit from getting rid of the infection. It is recommended to start by applying organic treatment options, working up to the more potent synthetic, chemical fungicides if necessary. Organic options won’t kill the fungus, but will prevent it from spreading. Dissolve ½ teaspoon of baking soda and one teaspoon of liquid soap in a gallon of water. Using a spray bottle, spray on tops and bottoms of leaves until the mixture drips off. Repeat every two weeks until existing spots stop enlarging and new spots no longer appear. Spray a copper-based fungicidal soap on the leaves, coating the top and bottom leaf surfaces. Reapply as directed on the product label. Copper penetrates the leaf surface and prevents germination of spores so the fungus cannot spread. Apply an all-purpose fungicide to the entire plant, following the label instructions carefully.

Root rot

Soft root rot can be caused by over-watering or pathogenic infection.

Solutions: These are the solutions for root rot: Stop applying water and allow the plant to dry out. In the case of potted plants, the gardener can remove plant from its container and lay it on a sheet of paper in a shady spot to speed the drying process. Cut away black mushy root material until healthy white material is reached. Sprinkle root ball with anti-fungal powder. Repot using sterilized potting mixture but don't water for first couple of days. Ensure that the new pot offers adequate drainage. Terracotta pots can absorb moisture into their walls. Adopt an appropriate watering regime. For most potted plants, refrain from watering until the first inch or two of the soil is dry to the touch. Even plants that prefer to be kept "evenly moist" should never be allowed to sit in soggy soil. Outdoor plants should not be receiving so much water that it pools at the surface of the soil.

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Weed Control

Weeds

Annual bluegrass is native to temperate Eurasia but has been introduced to much of the rest of the world. It is considered a nuisance within its native range and invasive outside of it. This large range is partially due to high phenotypic plasticity, which allows annual bluegrass to adapt more readily to a variety of habitats. Additionally, each plant can produce thousands of seeds annually that can be spread by livestock, birds, wind, water, and clothes/boots. While a variety of herbicides have been shown to be effective in controlling annual bluegrass, some populations have evolved resistances. Thus, a rotation of different herbicides can be more effective. Alternatively, hand pulling can be effective at controlling small infestations, while mulching can also help suppress weed development.

How to Control it

If annual bluegrass becomes a problem, it can be dug up while it’s still growing, before it seeds and spreads into larger patches. Otherwise, herbicides may be required. If so, it is best to start treatments before the seeds germinate, sometime in the fall, in order to prevent new infestations. A second application may be needed 8 to 10 weeks later. Solitary plants can also be removed by hand or with a hoe before seed production starts. This can be effective as long as it’s done frequently.

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Distribution Map

Habitat

Waste places, cultivated land, grassland

Native

Cultivated

Invasive

Potentially invasive

Exotic

No species reported

More Info

Plant Type

Grass

Flower Color

White

Green

Yellow

Bloom Time

Spring, Early summer, Mid summer, Late winter

Leaf Color

Green

Name story

Annual bluegrass

Annua refers to the meaning of annual. The bluegrass in the common name refers to the bluish appearance of the massed grass in late Spring. Although Poa annua is commonly considered as a solely annual plant for its name, perennial biotypes do exist.

Symbolism

Psychic powers, Protection. It symbolizes food, concealment and hardiness.

Usages

Garden Use

Annual bluegrass is a popular turf in cool and warm climates since it spreads readily. It's often used in lawns or causeways, where its vibrant green clumps are pleasant to the eye. This grass sprouts tall whispy seed stalks in the summer months, which can be raked away. It grows in full sun but will turn brown in hotter weather during the summer.

Scientific Classification

Phylum

Vascular plants

Class

Monocotyledons

Order

Family

Grass

Genus

Meadow-grasses

Species

Annual bluegrass

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Asthma-plant

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Monarch fern

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Moisture-loving, keep the soil moist but do not let water accumulate.

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Add to My Garden

Annual bluegrass

Poa annua

Also known as: Wintergrass, Low spear grass

Annual bluegrass (Poa annua) is a low-growing grass native to Europe and Asia. Poa annua is known commonly as both annual bluegrass and poa. The Latin name is derived from the Greek word poa, which is a type of fodder grass.

Twice per week

Water

Full sun

Sunlight

Weeds

Care Guide for Annual bluegrass

Water

Fertilization

Fertilization once in spring.

Soil

Sand, Clay, Loam, Chalky, Acidic, Neutral, Alkaline

Sunlight

Full sun, Partial sun

Hardiness Zones

4 to 10

Know the light your plants really get.

Find the best spots for them to optimize their health, simply using your phone.

Download the App

Questions About Annual bluegrass

Watering

Pruning

Sunlight

Temperature

What should I do if I water my Annual bluegrass too much or too little?

How to water Annual bluegrass?

What should I consider when watering my Annual bluegrass?

Is pruning necessary for my Annual bluegrass?

How do I prune my Annual bluegrass?

Are there any cautions I should be careful with when pruning my Annual bluegrass?

Are there any tips for pruning my Annual bluegrass?

When should/shouldn't I prune my Annual bluegrass?

What should I look for when pruning my Annual bluegrass in different seasons?

How much sunlight should Annual bluegrass get per day to grow healthily?

What type of sunlight does Annual bluegrass need?

Can sunlight hurt plants? How to protect Annual bluegrass from sun and heat damage?

Should I protect Annual bluegrass from sun exposure?

What will happen if Annual bluegrass gets inadequate sunlight?

Does Annual bluegrass need special care about sunlight during its different growth stages?

How much light does Annual bluegrass need for photosynthesis?

Are there any cautions or tips for sunlight and Annual bluegrass?

What is the optimal temperature for Annual bluegrass?

Temperature requirements for first year or seedling Annual bluegrass

How can I protect Annual bluegrass from extreme temperatures?

Dormant season temperature recommendations for Annual bluegrass

Get tips and tricks for your plants.

Keep your plants happy and healthy with our guide to watering, lighting, feeding and more.

Download the App

Common Pests & Diseases

Common issues for Annual bluegrass based on 10 million real cases

Aged yellow and dry

Natural aging can cause leaves to turn yellow and dry out.

Learn More

Underwatering

Leaves may wilt for a variety of reasons.

Learn More

Brown spot

This infection can cause brown spots or patches to appear on the plant.

Learn More

Root rot

Soft root rot can be caused by over-watering or pathogenic infection.

Learn More

Treat and prevent plant diseases.

AI-powered plant doctor helps you diagnose plant problems in seconds.

Download the App

Weed Control

Weeds

How to Control it

Do you have weeds in your garden?

Differentiate them from your plants by a picture, and learn how to control them.

Download the App

Distribution Map

Habitat

Waste places, cultivated land, grassland

Map

Native

Cultivated

Invasive

Potentially invasive

Exotic

No species reported

More Info

Plant Type

Grass

Flower Color

White

Green

Yellow

Bloom Time

Spring, Early summer, Mid summer, Late winter

Leaf Color

Green

Name story

Annual bluegrass

Symbolism

Psychic powers, Protection. It symbolizes food, concealment and hardiness.

Usages

Garden Use

Scientific Classification

Phylum

Vascular plants

Class

Monocotyledons

Order

Grasses, sedges and allies

Family

Grass

Genus

Meadow-grasses

Species

Annual bluegrass

Find your perfect green friends.

Plan your green oasis based on your criteria: plant type, pet safety, skill level, sites, and more.

Download the App

Related Plants

Hairy beggarticks

Bidens pilosa

Chandelier plant

Kalanchoe delagoensis

Phymatosorus scolopendria