Poa annua ( Annual Bluegrass )

Characteristics

Cultivar:	n/a
Family:	Poaceae
Size:	Height: 0.83 ft. to 1 ft. Width: 0.5 ft. to 0.67 ft.
Plant Category:	annuals and biennials, turf grasses,
Plant Characteristics:	low maintenance,
Foliage Characteristics:
Foliage Color:	green,
Flower Characteristics:
Flower Color:	greens,
Tolerances:	deer, drought, heat & humidity, pollution, rabbits, seashore, slope, wind,

Requirements

Bloomtime Range:	Early Summer to Late Summer
USDA Hardiness Zone:	5 to 8
AHS Heat Zone:	Not defined for this plant
Light Range:	Part Shade to Full Sun
pH Range:	4.5 to 7.5
Soil Range:	Mostly Sand to Mostly Clay
Water Range:	Normal to Normal

Plant Care

Fertilizing

How-to : Fertilization for Annuals and Perennials

Annuals and perennials may be fertilized using: 1.water-soluble, quick release fertilizers; 2. temperature controlled slow-release fertilizers; or 3. organic fertilizers such as fish emulsion. Water soluble fertilizers are generally used every two weeks during the growing season or per label instructions. Controlled, slow-release fertilizers are worked into the soil ususally only once during the growing season or per label directions. For organic fertilizers such as fish emulsion, follow label directions as they may vary per product.

How-to : Fertilize Lawn

Now is the time to fertilize the lawn.

Light

Conditions : Partial Shade

Partial Shade is defined as filtered light found beneath trees with high limbs. Partial shade usually offers some protection from direct afternoon sun.

Conditions : Part Sun

Part Sun refers to filtered light, with most sun being received during the afternoon hours. Shade usually occurs during the morning hours.

Conditions : Sun

Sun is defined as the continuous, direct, exposure to 6 hours (or more) of sunlight per day.

Conditions : Light Conditions

Unless a site is completely exposed, light conditions will change during the day and even during the year. The northern and eastern sides of a house receive the least amount of light, with the northern exposure being the shadiest. The western and southern sides of a house receive the most light and are considered the hottest exposures due to intense afternoon sun.

You will notice that sun and shade patterns change during the day. The western side of a house may even be shady due to shadows cast by large trees or a structure from an adjacent property. If you have just bought a new home or just beginning to garden in your older home, take time to map sun and shade throughout the day. You will get a more accurate feel for your site's true light conditions.

Conditions : Partial Sun, Partial Shade

Part sun or part shade plants prefer light that is filtered. Sunlight, though not direct, is important to them. Often morning sun, because it is not as strong as afternoon sun, can be considered part sun or part shade. If you live in an area that does not get much intense sun, such as the Pacific Northwest, a full sun exposure may be fine. In other areas such as Florida, plant in a location where afternoon shade will be received.

Conditions : Full to Partial Sun

Full sunlight is needed for many plants to assume their full potential. Many of these plants will do fine with a little less sunlight, although they may not flower as heavily or their foliage as vibrant. Areas on the southern and western sides of buildings usually are the sunniest. The only exception is when houses or buildings are so close together, shadows are cast from neighboring properties. Full sun usually means 6 or more hours of direct unobstructed sunlight on a sunny day. Partial sun receives less than 6 hours of sun, but more than 3 hours. Plants able to take full sun in some climates may only be able to tolerate part sun in other climates. Know the culture of the plant before you buy and plant it!

Conditions : Light and Plant Selection

For best plant performance, it is desirable to match the correct plant with the available light conditions. Right plant, right place! Plants which do not receive sufficient light may become pale in color, have fewer leaves and a "leggy" stretched-out appearance. Also expect plants to grow slower and have fewer blooms when light is less than desirable. It is possible to provide supplemental lighting for indoor plants with lamps. Plants can also receive too much light. If a shade loving plant is exposed to direct sun, it may wilt and/or cause leaves to be sunburned or otherwise damaged.

Conditions : Full Sun

Full Sun is defined as exposure to more than 6 hours of continuous, direct sun per day.

Watering

Conditions : Regular Moisture for Outdoor Plants

Water when normal rainfall does not provide the preferred 1 inch of moisture most plants prefer. Average water is needed during the growing season, but take care not to overwater. The first two years after a plant is installed, regular watering is important. The first year is critical. It is better to water once a week and water deeply, than to water frequently for a few minutes.

Planting

How-to : Lawn Soil Preparation

Soil should provide a good rooting environment that supplies adequate moisture, air, and nutrients. The new lawn site should first be worked to insure uniform drainage and water penetration. Remove old sod or existing weeds, which can prevent new seeds from rooting properly. This can be done by hand or with a nonselective herbicide that will kill roots too. Add limestone if the pH of your soil is too low (6.0 or lower); consult your garden center for specific rates to properly adjust pH. Also add a starter fertilizer, which is high in phosphorus (important for new root growth). Organic matter in the form of peat moss or rotted compost may be added at a rate of 1 cubic yard per 1000 sq. feet area . Rake all these materials together, smooth, then firm the seedbed with a roller prior to seeding. Finally soak the seeding area and keep it moist until you are ready to seed.

How-to : Lawn Seed Selection

When planning a lawn consider your climate and the use the lawn will get. Some species do not grow well when subjected to excess foot traffic, others form a denser mat which resists wear.

Grass seed are characterized according to temperature. Cool season grasses are best suited to the northern half of the United States, while warm season grasses are best for the southern half of the US. Cool season grasses, generally grown from seed, withstand cold winters, but suffer in hot, dry summer conditions and should not be mowed too closely. They are usually established during their active growing season, the cooler months.

Warm season grasses, can be seeded, grown from plugs (small circles of turf), sprigs (stolons or rhizomes) or sodded, and are more heat, drought and wear tolerant than cool season grasses. They also can be mowed more closely and will lose color when temperatures creep below 50 degrees F. Warm season grasses are usually established during their growing season, the warmer months. Sod can be layed any time of year.

Instead of a single type of seed, it may be preferable to go with a mixture of different types of seed. While a single type of seed will produce a lawn which looks more uniform, this lawn will be more susceptible to disease and other damage resulting in loss of the lawn. A mixture of seed will provide you with some insurance as a population of different grass types will be better able to survive any adversity.

Warm Season Grasses include: Common Bermuda, Hybrid Bermudas, Centepede, Zoysia, St. Augustine, Buffalo Grass, Bahaia. Cool Season Grasses include: Fescues, Perennial Bluegrass, Rye, Bentgrass.

How-to : Seeding a Lawn

Late summer through early fall are generally the best times to sow grass seed. Sow the seed with a rotary spreader to assure uniform distribution. After seeding, roll the surface to ensure that the seeds are making good contact with the soil. Water seedbed thoroughly and keep it uniformly moist until all seed has sprouted (this may take 2 to 3 weeks). The first mowing cut should be high (about 2 inches) and make sure the mower blades are sharp.

How-to : Laying Sod

Sod, is a ready-made lawn that was grown on a sod farm and harvested to be transplanted elsewhere. It is more expensive than seeding but it saves significant time compared to seeding. It is also useful on slopes or areas where erosion is a problem. Sod is essentially mature top growth, roots, and only a minimal amount of soil. When laying sod, first prepare the soil as you would when seeding. Then lay the rolls out on the bed and stagger the seams where strips end, pushing edges together tightly. If sodding on a slope, you may want to secure sod to ground with long pins or nails, which should be removed once roots have established. Keep well watered until the roots become established.

Problems

Weeds : Preventing Weeds and Grass

Weeds rob your plants of water, nutrients and light. They can harbor pests and diseases. Before planting, remove weeds either by hand or by spraying an herbicide according to label directions. Another alternative is to lay plastic over the area for a couple of months to kill grass and weeds.

You may apply a pre-emergent herbicide prior to planting, but be sure that it is labeled for the plants you are wishing to grow. Existing beds may be spot sprayed with a nonselective herbicide, but be careful to shield those plants you do not want to kill. Non-selective means that it will kill everything it comes in contact with.

Mulch plants with a 3 inch layer of pinestraw, pulverized bark, or compost. Mulch conserves moisture, keeps weeds down, and makes it easier to pull when necessary.

Porous landscape or open weave fabric works too, allowing air and water to be exchanged.

Weeds : Annual Bluegrass

Annual Bluegrass is a cool season grass that germinates and thrives during the fall, winter and early spring. Its characteristic bright green color and tufted, fine texture makes it stand out in the normal lawn. Another way to distinguish this grass is by looking for the tell-tale, transparent white lines on both side of the midvein on newer shoots. Holding the blade up to light will make this job easier. On grass that has not been frequently mowed, white flowers, or seed heads, will appear as pyramidal clusters. These seed heads will mature somewhere between May and July, depending on where you live. Once warmer weather has set in, the grass will die back, leaving unsightly brown patches in the lawn, shrub border or flowerbed. Though the annual form is described here, there are perennial forms of bluegrass too. Be careful, as Kentucky Bluegrass, Poa pratensis, a commonly planted lawn grass, closely resembles annual bluegrass.

Prevention and Control: A healthy, thick lawn that is not overwatered or overfertilized is your best bet for preventing the establishment of annual bluegrass. Also make sure that your lawn is well aerated, as compacted soils tend to favor weeds. Mowing at the proper height will also discourage establishment. If this weedy grass becomes a problem in the garden, try pulling it out by hand while still young, prior to seed set. A good layer of mulch around vegetables, shrubs, and flowerbeds will deter establishment and make pulling by hand easier. If the infestation is too large to pull by hand, spot treat with a recommended herbicide. Always read the label's directions for use.

Lawns: To prevent emergence, use a pre-emergent herbicide according to label directions.

Miscellaneous

Conditions : Deer Tolerant

There are no plants that are 100% deer resistant, but many that are deer tolerant. There are plants that deer prefer over others. You will find that what deer will or will not eat varies in different parts of the country. A lot of it has to do with how hungry they are. Most deer will sample everything at least once, decide if they like it or not and return if favorable. A fence is the good deer barrier. You may go for a really tall one (7 to 8 feet), or try 2 parallel fences, (4 to 5 feet apart). Use a wire mesh fence rather than board, since deer are capable of wiggling through a 12 inch space.

Conditions : Pollution Tolerant

Air pollution is becoming a bigger problem each day. Pollutants in our air damage plants. The plants are damaged by absorbing sulfur dioxide, ozone, peroxyacetyl nitrate, ethylene, and nitrogen dioxide through their pores. Cell membrane damage may result in leaf drop, blotched or burnt looking leaves, or off-colored tissue between veins. Vehicles and industrial processes are the key culprits and conditions worsen on hot summer days. Though planting only pollution tolerant plants is not the solution to this problem, it is a visual band aid. Your Cooperative Extension Service may have a list of plants that are more pollution tolerant in your area.

Conditions : Rabbit Tolerant

As cute as they are, rabbits can really damage a vegetable garden. Young, tender lettuce plants seem to be their favorite. If a free-roaming dog is not a possibility for you, consider installing raised vegetable beds and covering tender shoots with netting. If you have ample room, you can opt to plant enough for you and the bunnies. Scents don't always repel animals, as they get used to them and are often washed off in the rain.

Conditions : Salt Tolerant

Anyone that lives close to the coast or in areas where soil salt content is high, can appreciate a plant that is salt tolerant. Salt damage is usually worse where the climate is arid: there is not enough rainfall to wash built up salts from the soil. It takes about 30 inches of rainfall a year to move salt through the soil. Plants that have salt damage usually have yellow leaves, brown tips or margins, and leaf drop. Soils may have a crusty white layer, too. Salt tolerant plants are often natives or introduced plants that have evolved in salty conditions.

Conditions : Slope Tolerant

Slope tolerant plants are those that have a fibrous root system and are often plants that prefer good soil drainage. These plants assist in erosion control by stabilizing/holding the soil on slopes intact.

Conditions : Wind Tolerant

Plants that are wind tolerant usually have flexible, strong branches that are not brittle. Wind tolerant plants often have thick or waxy leaves that control moisture loss from whipping winds. Native plants are often the best adapted to not only wind, but also soil and other climatic conditions.

Conditions : Erosion Control

Plants that help to control erosion have fibrous root systems that help to keep soil intact. Leaves and the overall form of a plant can prevent erosion by breaking up water droplets before they hit the ground, lessening splashing and runoff.

Glossary : Low Maintenance

Low maintenance does not mean no maintenance. It does mean that once a plant is established, very little needs to be done in the way of water, fertilizing, pruning, or treatment in order for the plant to remain healthy and attractive. A well-designed garden, which takes your lifestyle into consideration, can greatly reduce maintenance.

Glossary : Some Sand

Some Sand refers to a soil that drains fast, but has lower water holding capacity due to the presence of a little organic matter. A good workable soil that needs added fertilizer due to lower fertility levels and adequate water. Usually gray in color. Forms a loose, crumbly ball that easily falls apart when squeezed in the hand.

Glossary : Sandy Loam

Sandy Loam refers to a soil that drains well, with excellent air space, and evenly crumbled texture when squeezed in the hand. A good workable garden soil that benefits from added fertilizer and proper watering. Dark gray to gray-brown in color.

Glossary : Loam

Loam is the ideal soil, having the perfect balance between particle size, air space, organic matter and water holding capacity. It forms a nice ball when squeezed in the palm of the hand, but crumbles easily when lightly tapped with a finger. Rich color ranges between gray brown to almost black.

Glossary : Some Clay

Some Clay refers to a soil that is loam-like, but heavier. Drainage is not bad, prolonged periods of rain cause bog-like conditions. Rich in nutrients, but needs the addition of organic matter to improve texture. Easily forms a ball when squeezed and requires a firm tap with finger to crumble. Light brown to slightly orange color.

Glossary : Annual

An annual is any plant that completes its life cycle in one growing season.

Glossary : Grass

Grass: A member of the Poaceae family, usually having round, hollow or solid stems with regularly spaced nodes. Seed are produced on spikes in the form of a raceme, panicle, or spike.

Conditions : Site Conditions

When setting criteria for site conditions, check boxes that apply to your planting area. This will narrow the search for appropriate plants. Naturally, you'll need to select a USDA Hardiness Zone. Selecting a specific soil type and pH are just as important as light and water conditions because they enable a search that will find plants best suited to your site.

Glossary : Plant Characteristics

Plant characteristics define the plant, enabling a search that finds specific types of plants such as bulbs, trees, shrubs, grass, perennials, etc.

Glossary : Soil Types

A soil type is defined by granule size, drainage, and amount of organic material in the soil. The three main soil types are sand, loam and clay. Sand has the largest particle size, no organic matter, little to no fertility, and drains rapidly. Clay, at the opposite end of the spectrum, has the smallest particle size, can be rich in organic matter, fertility and moisture, but is often unworkable because particles are held together too tightly, resulting in poor drainage when wet, or is brick-like when dry. The optimum soil type is loam, which is the happy median between sand and clay: It is high in organic matter, nutrient-rich, and has the perfect water holding capacity.

You will often hear loam referred to as a sandy loam (having more sand, yet still plenty of organic matter) or a clay loam (heavier on the clay, yet workable with good drainage.) The addition of organic matter to either sand or clay will result in a loamy soil. Still not sure if your soil is a sand, clay, or loam? Try this simple test. Squeeze a handfull of slightly moist, not wet, soil in your hand. If it forms a tight ball and does not fall apart when gently tapped with a finger, your soil is more than likely clay. If soil does not form a ball or crumbles before it is tapped, it is sand to very sandy loam. If soil forms a ball, then crumbles readily when lightly tapped, it's a loam. Several quick, light taps could mean a clay loam.

Glossary : Tolerant

Tolerant refers to a plant's ability to tolerate exposure to an external condition(s). It does not mean that the plant thrives or prefers this situation, but is able to adapt and continue its life cycle.

Glossary : Drought Tolerant

Very few plants, except for those naturally found in desert situations, can tolerate arid soils, but there are plants that seem to be more drought tolerant than others. Plants that are drought tolerant still require moisture, so don't think that they can go for extended period without any water. Drought tolerant plants are often deep rooted, have waxy or thick leaves that conserve water, or leaf structures that close to minimize transpiration. All plants in droughty situations benefit from an occasional deep watering and a 2-3 inch thick layer of mulch. Drought tolerant plants are the backbone of xeriphytic landscaping.

Glossary : Ground Cover

Aground cover is any low growing plant that is planted in a mass to cover the ground. Shrubs, vines, perennials, and annuals can all be considered ground covers if they are grouped in this fashion. Ground covers can beautify an area, help reduce soil erosion, and the need to weed.

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