- Fast Facts About Kentucky Bluegrass
- Caring For Kentucky Bluegrass Lawns: Tips On Planting Kentucky Bluegrass
- Information on Kentucky Bluegrass
- Kentucky Bluegrass Maintenance
- Kentucky Bluegrass – America’s Favorite Cool Season Grass
- Kentucky Bluegrass Seeds 7100
Fast Facts About Kentucky Bluegrass
Ever wonder how the most commercially valuable cool-season turfgrass in America got its name? Kentucky bluegrass, or Poa pratensis, is neither blue, nor did it originate in Kentucky, at least not the varieties that most are familiar with. But there is a believable explanation of how this species got its name.
European settlers are generally thought to have brought seed of the species with them when they established their homesteads in central and northern Kentucky in the 17th and 18th centuries. Kentucky bluegrass grows well as a pasture grass on the limestone soils of the region. This cool-season, sod-forming perennial grass is also palatable for grazing animals. And that’s thought to be one of the reasons it was established in the central and northern regions of Kentucky.
As previously mentioned, the species, like all familiar grass species, is green. But in areas where common meadow grass is allowed to grow to its mature height of 2 to 3 feet, the plants put on small silvery-blue flowers.
If you get the privilege of visiting eastern Oregon or northern Idaho, where Kentucky bluegrass (many different cultivars) is grown for the commercial production of seed, you will be delighted at seeing the waving mature grass plants just prior to harvesting. Whether you see blue or not, it’s a beautiful sight.
Kentucky bluegrass is the most commercially valuable cool-season turfgrass in America. It’s almost universally found on lawns in much of the Midwest and Northeast. Turfgrass breeders are constantly working with the species, seeking varieties that are ever-more attractive, durable and resistant to stresses, such as heat, drought, insects and diseases.
Few of these varieties are being developed and tested as a pasture or forage grass. Palatability isn’t a characteristic homeowners, sports field managers or golf course superintendents value.
Kentucky bluegrass is the turf grass species most widely used in the northern half of the U.S. It produces a dark-green, medium textured, dense turf and spreads by underground rhizomes that can self-repair damaged spots.
A cool season turf grass, Kentucky bluegrass can go dormant in hot summers without adequate irrigation, and is susceptible to diseases and weeds. It prefers full sun but tolerates some shade; it does not tolerate salt spray. Some experts recommend a mixture of 15 percent perennial ryegrass and 85 percent Kentucky blue for a more disease-resistant and heat-tolerant turf.
A Kentucky bluegrass lawn can be established from sod or seed sown in the fall at two to three pounds per 1,000 square feet. Kentucky bluegrass needs a well-drained, moist, fertile soil with a pH between 6 and 7.
Because of its shallow root system Kentucky bluegrass needs frequent watering (1 ½ inches per week in hot weather) to stay green in the summer. A bluegrass lawn needs water when the blades get a bluish cast or when walking across the lawn leaves footprints. It will survive drought by turning brown.
Mowing Kentucky Blue Grass
Mow no more than 1/3 of the blade height at a time, to a height of 1 ½ to 3 inches. Mowing too low encourages weeds. High mower yields deeper rooting and greater heat and drought tolerance.
Fertilizing Kentucky Blue Grass
A soil test is the only way to know for sure what type of fertilizer and amendments the soil needs before planting. Kentucky Bluegrass needs well-prepared, well-drained soil. Organic matter (e.g. rotted manure or compost) applied before planting at a rate of three to six cubic years per 1,000 square feet and tilled to 8-10 inches improves the structure and fertility of the soil.
During active growth Kentucky bluegrass needs four to six pounds of nitrogen per 1,000 square feet.
Want to Learn More About Growing Kentucky Bluegrass?
Contact your local seed sellers or extension service to find out the best varieties of Kentucky bluegrass for your location.
Most extension services also provide inexpensive soil text kits. Go to The National Institute of Food and Agriculture homepage to find the extension office nearest you.
The following websites have good information about growing a Kentucky bluegrass lawn:
Kentucky Bluegrass, Texas Cooperative Extension.
The UC Guide to Healthy Lawns: Kentucky bluegrass.
Here’s a .pdf file entitled Kentucky Bluegrass Lawns via Kansas State University.
And of course, who can forget Bill Murray and Chevy Chase’s discussion about bluegrass from the Comedy Caddyshack?
Caring For Kentucky Bluegrass Lawns: Tips On Planting Kentucky Bluegrass
Kentucky bluegrass, a cool season grass, is a species native to Europe, Asia, Algeria and, Morocco. However, even though this species is not native to the United States, it is grown all over the East Coast, and can also be grown in the west with irrigation.
Information on Kentucky Bluegrass
What Does Kentucky Bluegrass Look Like?
At maturity, Kentucky bluegrass is about 20-24 inches tall. It can be recognized quite easily because of its “V” shaped leaves. Its rhizomes allow it to spread and create new grass plants. Kentucky bluegrass rhizomes grow quite quickly and form a thick sod in the spring.
There are over 100 cultivars of this grass and most stores selling grass seeds will have a variety to choose from. Bluegrass seed is also frequently sold mixed with other grass seeds. This will give you a more balanced lawn.
Planting Kentucky Bluegrass
The best time to plant Kentucky bluegrass seed is in the fall when the soil temperatures are between 50-65 degrees F. The soil needs to be warm enough for germination and root development so that it will survive through the winter. You can plant Kentucky bluegrass on its own or combine several varieties for a diverse blend.
Kentucky Bluegrass as Forage Crop
Kentucky bluegrass is sometimes used for grazing livestock. If allowed to develop properly, it can withstand low grazing. Because of this, it does well as a grazing crop when mixed with other cool season grasses.
Kentucky Bluegrass Maintenance
Because this is a cool season grass, it requires at least 2 inches of water per week to keep it healthy, growing, and green. If your area gets less water than this, it will be necessary to irrigate. If irrigation is required, the turf should be watered in small amounts daily instead of once per week in large amounts. If the grass does not get enough water, it may go dormant in the summer months.
Kentucky bluegrass will do much better when nitrogen is applied. In the first year of growing, 6 pounds per 1000 square feet may be needed. Years after, 3 pounds per 1000 square feet should be adequate. Less nitrogen may be needed in areas with rich soil.
Usually, if weeds are allowed to grow, Kentucky bluegrass lawns will be covered in dandelions, crabgrass, and clover. The best form of control is using a pre-emergent herbicide on lawns annually. The best time to do this is in the early spring before weeds are noticeable.
Mowing Kentucky Bluegrass Lawns
Young grass does best when kept at a 2-inch height. It should be mowed before it ever reaches 3 inches. Grass should never be mowed lower than this because it would cause young seedlings to be pulled up and ruin the overall health of the lawn.
Kentucky Bluegrass – America’s Favorite Cool Season Grass
Kentucky bluegrass is by far the favorite and most widely used of all the bluegrass species.
It is one of the more beautiful cool season lawn grasses. It is known for its excellent color, density and texture. It can be purchased in both seed or sod. Kentucky bluegrass seed is commonly included in seed mixtures with cool season turf grasses.
How to Identify K. Bluegrass
The easiest method of identifying K. bluegrass is to look for the boat shaped tip. If you look carefully, the tip of the blade folds together to resemble the bow of a boat. If you pull the length of the grass through your fingers, the tip will split, leaving two small points. Only orchardgrass has a similar shaped tip.
You can also look for very narrow, upright standing grass blades that come to a point. Other grass types, such as fescue will have much wideer blades in comparison.
Bluegrass forms a dense and attractive turf. For some people, the thin blades are more appealing than wider bladed grasses.
Kentucky Bluegrass has a solid advantage over other cool season grasses by its ability to spread. The fact that it can spread and heal itself when damaged is probably the greatest reason for its popularity. It spreads through the production of rhizomes. See Plant Structure for a complete explanation of rhizomes. Rhizomes are stems that grow horizontally just below the surface of the ground. Each rhizome produces a “node” every few inches along its length from which a new bluegrass plant will sprout. Bluegrass is an excellent choice for busy lawns where backyard activities tend to wear down the turf. Athletic fields will often use a combination of bluegrass and perennial ryegrass. The bluegrass will heal damages and perennial ryegrass is used for its high wear resistance.
Kentucky bluegrass seed is often blended with turf-type tall fescue seed when grown for sod production. Most tall fescue varities don’t have the structure to hold sod together very well, but bluegrass does. When sod is harvested, the roots are cut, but the rhizomes from the bluegrass keep the sod from falling apart.
Sports fields planted with fescue will usually add K. Bluegrass. This is because the grass will spread and heal any damaged spots. Fescue doesn’t produce runners so bluegrass has this as an advantage and is almost always included in the mix.
Since the rhizomes grow underground, they help ensure the survival of the plant. It can survive damage that would kill other grasses. Even if the grass is removed at ground level, bluegrass could still grow back because of the underground growing points on the rhizomes.
Kentucky bluegrass has better cold tolerance than other cool season grasses. It can withstand periods of very cold weather that would normally damage fescue or ryegrass. The adaptation zone for bluegrass extends through the cool/humid and cool/arid regions.
However, bluegrass doesn’t do well in the south. It is too hot. I have heard from people as far south as Dallas, TX asking how to keep their bluegrass alive. It is always best to choose a grass that does well where you live.
Kentucky Bluegrass is considered a high water user in summer, partly due to a shallower root system than other grasses. Without proper irrigation or sufficient rainfall in summer, bluegrass is one of the first grasses to go dormant.
On the up side, however, even after extended drought, bluegrass has the remarkable ability to recover from dormancy without damage.
Another disadvantage is that Kentucky Bluegrass is not very shade tolerant and will thin or die if planted in heavy shade. Rough bluegrass, on the other hand, is a variety of bluegrass that has much better shade tolerance. Shade grasses, such as fine fescues, are also compatible with Kentucky bluegrass.
Common and Improved Bluegrass Varieties
There are two basic categories of Kentucky bluegrass: Common bluegrass varieties and improved bluegrass varieties. To see the specific varieties, click on the Cultivars page.
Common bluegrass varieties are the oldest cultivars of Kentucky bluegrass. The older varieties are used in many seed mixtures and is the type usually seen growing in home lawns. The term used for these older varieties have become known as the “public varieties”. It is a very attractive lawn grass with all the attributes listed above. However, the major drawback is that the older cultivars are highly susceptibility to the fungal grass disease called “leaf spot”.
Common bluegrass varieties are best used on sites that will not be receiving regular fertilization and irrigation. This is because common bluegrass will become too disease prone when placed on a fertility program.
This presents a problem with seed mixtures sold in lawn and garden stores. Many of these stores that offer bluegrass, sell the older “public variety”. Again, it is not a problem unless you intend to fertilize regularly throughout the season. It is better, if possible, to purchase your seed through a store or warehouse that supplies the landscape and turf industry. Many of these warehouses sell to the public and their employees have a better product knowledge. You can usually get improved Kentucky bluegrass blends that are resistant to leaf spot.
Improved varieties were released many years after common bluegrass varieties hit the market. These cultivars have been developed for athletic and sports fields where there is more intense maintenance. Improved bluegrass was designed to be much more resistant to various grass diseases and also have a slower growth rate. Some varieties make a great lawn grass.
Irrigation and Drought Tolerance
Bluegrass has the natural ability to survive several weeks or even months of drought. Following a drought, new growth will spring up from the rhizomes. Bluegrass has a shallow root system, so if it doesn’t rain, it will need to be watered a couple times a week during the summer to keep it green. Kentucky bluegrass should receive at least 1/2 inch with each watering.
Kentucky bluegrass can be mowed as low as 1.5 inches in the cooler times of the year. This height increases to 3 to 4 inches in summer to help it survive the summer heat. Personally, I rarely adjust my mower below 4 inches all year. That may seem high if you are not used to it, but the grass quickly adjusts. The additional blade length enables the grass to endure drought and heavy traffic.
In the industry, the amount of fertilizer is stated in pounds of Nitrogen per 1000 sq. ft. per year. Kentucky bluegrass requires 4-5 lbs of nitrogen per 1000 sq. ft. per year. There is an easy formula for determining how much fertilizer to apply regardless of the percent of nitrogen in the bag. Click on getting the correct fertilizer rate.
Bluegrass can suffer damage from white grubs, billbugs, sod webworms, and leafhoppers. White grub controls can be applied as a preventative. You can use products like Merit by Bayer, Grub-Ex by Scotts, or similar products. With these products, they only kill the insects that feed on the grass and not beneficial insects. Insecticides can also be applied as soon as damage is seen. Damage can occur quickly, so it is important to monitor for insects or be aware of the time when they are active.
“Leaf Spot”, “Melting Out Disease”, and “Rust” are three of the more common diseases that affect the common bluegrass varieties. They can best be controlled by proper watering techniques and infrequent use of high nitrogen fertilizers. However, rust problems are usually indicative of low nitrogen soils. A little nitrogen fertilizer will help with rust.
Very often when I see rust on grass, I will check to see if it is on the bluegrass. From my experience it will often begin there and spread to other grass or remain only on the bluegrass.
Necrotic Ring Spot is another serious disease of heavily fertilized bluegrass. Once established, it is difficult to control. Fungicide treatments are necessary.
Preventative maintenance includes core aeration to relieve soil compaction and to help control thatch. As with all grasses, knowledge on the use of organics to build up beneficial micro-organisms is extremely helpful. Beneficial micro-organisms are the natural enemies of disease pathogens.
Consider our product, AgriGro Turf Formula or Bountiful Harvest Biostimulant. Research has shown it increases beneficial microorganisms 3400% in the first 24 hours after application. This explosion of microorganisms breaks down soil elements fast and delivers nutrients to the roots. This feeds the turf with less applied fertilizer. It is shown to suppress many diseases.
Click here to see what AgriGro can do for your lawn.
Other Bluegrass Varieties
Rough bluegrass is used in shaded and damp areas. It does not perform well in full sun or in arid locations. The exception is when is it used in winter to overseed dormant burmudagrass. This is about the only time when rough bluegrass can make a beautiful, full sun lawn.
Annual bluegrass is grassy weed with a one year life cycle. It is a “winter annual”, meaning it germinates and matures in the fall, lives through the winter, and then produces seed in the spring before it dies. It is one of the first grasses to green up in the spring. It is most noticeable when other grasses haven’t yet come out of dormancy.
It presents the biggest problem in closely mowed turf where more sunlight reaches the blades. It can even survive on golf green that are mowed at 1/4 inch. Lawns that are mowed at 3 or 4 inches have less problems with annual bluegrass. It can easily thrive in a variety of soil conditions including heavily compacted soil. By the time warm season grasses green up, annual bluegrass has started dying back.
In areas like gravel driveways, Round-Up can be sprayed to control it and other weeds. In lawns, try to manage your grass is such a way that encourages the lawn grass and not the annual bluegrass. The easiest way is to raise the mower blade to mow at higher levels. It doesn’t prefer sites where there is too much competition, so maintaining a thick turf is helpful. To control annual bluegrass in warm season grasses, you can try overseeding in the fall with ryegrass. A pre-emergent applied in the fall before annual bluegrass germinates will help. However, only use a pre-emergent if you don’t intend to overseed.
Coarse and Turf-Type Tall Fescue Grass
Tall fescue is one of the best cool season grasses. It is preferred by many because of its dark green color, wear resistance and heat tolerance. Click here to find out everything you need to know about tall fescue.
Fine Fescue Grass
The fine fescue grasses are known for their exceptional shade and cold tolerance. They also have some of the narrowest blades of any grass type. Click here for detailed information about its climate range, uses and management.
Annual and Perennial Ryegrass
Ryegrass has come a long way with the introduction of new turf species. See all the pros and cons about using the perennial and annual varieties.
Overseeding Lawns – Detailed Tips and Techniques for a Beautiful Lawn
Lawn overseeding is one of the most overlooked practices by homeowners. However, it is one of the most important steps you can take to maintain a consistently thick and beautiful lawn. Find complete information on why and how to overseed correctly.
Watering a New Lawn
Watering a new lawn is very different from watering a mature lawn. When planting a new lawn, success will be greatly increased by learning proper watering techniques.
Understanding Organics and Organic Lawn Fertilization
An unbiased look at organic fertilizers, how they work and how to best use them to your advantage. Includes detailed information on natural organic fertilizers and organic/synthetic fertilizer blends.
All About Lawn Fertilization
Fertilizing a lawn can be tricky if you are not sure how to do it correctly. Find everything from understanding fertilizer ingredients to calculating fertilizer rates to planning your fertilizing schedule for the entire year and more.
Lawn Winterization Tips and Techniques
Fall winterization is the most important time for fertilizing cool season grasses. Warm season grasses do not receive the same treatment. Find everything you need to know to winterize both cool and warm season grasses.
Lawn Care Academy Products for Lawn and Garden
Lawn Care Academy’s list of quality products that will help you develop and maintain your lawn and garden.
Kentucky Bluegrass to Lawn Care Academy Home
Kentucky Bluegrass Seeds 7100
Kentucky Bluegrass Seeds 7100 The basis of any good lawn seed mixture. While slower to germinate, Kentucky Bluegrass thickens into a fine, lush green turf. It has excellent wear tolerance and a high self repairing capacity due to its sod forming ability.
How to Grow
3000 seed/gram For New Lawns, spread good clean topsoil to a depth of 15 cm (6”). Break up any clumps and rake level. For repairing old lawns, mow grass close to the soil surface. Rake vigorously to remove clippings and accumulated thatch. Add top soil to fill in any low spots then rake smooth. Grass seed can be applied in spring when the soil warms and again from mid August to late September. Note that cold soil can greatly extend the normal germination time. Sow seed at a rate of 454 g per 40 sq. m (1 lb per 440 sq. ft.) Apply twice at half rate over the area in a criss-cross pattern. Lightly rake the seeded area to just barely cover the seed with soil. Roll once with a roller at half capacity if the soil is light. Water with a fine spray for two or three weeks to keep the seedbed moist. Mow for the first time when seedlings reach 8 cm (3“) height. Kentucky Bluegrass takes about 3 weeks to germinate when both soil temperature and moisture conditions are ideal. Note that cold and/or dry soil can greatly extend the normal germination time.
Kentucky bluegrass (Poa pratensis) receives its name from its blue inflorescence, an open, branching, pyramid-shaped structure known as a panicle. The panicle is 1-1/2 to 5 inches long and 1 to 3 inches wide. The waving branches bear spikelets on their ends. Each spikelet has three to six flowers capable of producing abundant awnless seed.
A bluegrass plant ranges from 18 to 24 inches in height and is characterized by slender, upright stems. The stems are slightly flattened in shape.
The leaves vary in length from 2 to 10 inches and average 1/4 inch in width. The blades are flat or folded and feel soft to the touch. Take a good look at the veins of the leaf for an interesting characteristic of Kentucky bluegrass—along the keel are two oddly transparent veins sometimes compared to racing stripes. The tip of the leaf is considered boat-shaped. Each leaf arises from a sheath with large veins.
Kentucky bluegrass is capable of forming dense mats thanks to its abundant rhizomes, tough stems that grow horizontally under the ground. The rhizomes of bluegrass typically grow two to four inches beneath the surface of the soil, but sometimes deeper.
Kentucky bluegrass can be found growing wild across all of Kansas in a variety of sites. It does well in open woods and meadows, as well as sites where the soil has been disturbed, such as tilled fields and overgrazed pastures.
Despite its adaptation to this wide range of locations, bluegrass is actually rather specific in its preferences and will not truly thrive unless its needs are met. The soil must be well drained and medium in texture—Kentucky bluegrass cannot tolerate compacted clay. Its pH preference is 6.0 to 7.0. It will be most productive in areas of full sunlight, although it can stand some shade if it receives adequate moisture and nutrients.
Kentucky bluegrass really excels in climates where the average daily July temperature does not exceed 75 degrees and where the air is humid.
Photo courtesy of USDA NRCS
This species is a cool-season perennial. It takes off quickly in early spring and grows aggressively while the weather is cool, starting from the previous year’s roots and continuing with a fresh new crop of roots. It also puts out rhizomes with amazing rapidity, and can spread through additional shoots known as tillers.
Kentucky bluegrass flowers from May through July. It often reproduces asexually by forming seeds in the ovary wall of the flower. Most of the seeds, therefore, are clones of the mother plant. Once the flowering process is completed and the summer grows hot and dry, Kentucky bluegrass protects itself from drought damage by going dormant.
It turns green again as days become short and cool. During this second period of growth, the plant focuses on putting out more rhizomes, spreading itself to collect solar energy. Late in the fall, the growth slows down and carbohydrates are stored in the abundance of new rhizomes to provide the nutrients needed to start all over again in the spring.
Kentucky bluegrass is not a native of the United States, but rather Europe, northern Asia, and some of the mountainous areas of Algeria and Morocco. It arrived on our shores with settlers during the colonial period, and it spread across the nation with the pioneers.
Since that time, Kentucky bluegrass has made itself a desirable source of food and shelter to many different animals, ranging from insects to grazing mammals. It hosts May, June, and Japanese beetle grubs, while it provides forage to deer, turkey, and rabbits. Its seeds feed many different songbirds and rodents.
The forage value of Kentucky bluegrass is well known across the nation. It provides excellent nutrition to horses, cattle, and sheep when the weather is cool, although its production is limited when the temperatures rise. It can be seeded as a monoculture, but mixing it with a legume will increase its nutritional value still further and provide for the nitrogen needs of the grass stand, as well. Plant into either a tilled or a no-till seedbed with adequate fertility and an optimal pH value, no deeper than 1/4 inch. Once the stand is established, it can be grazed in the early spring as soon as the grass reaches five inches tall. Always leave a stubble of about two inches to prevent subsequent weed invasion.
The thick mat formed by Kentucky bluegrass is also excellent for erosion control purposes. It can be used to stabilize banks, pond edges, and field borders, and it is a good grass cover in orchards. The type and amount of maintenance bluegrass will require in this role will depend on the specific application. Where the height of the grass is not an issue, it will only need to be mowed once a year to control weeds and keep the stand looking its best.
Even in the hotter, drier climate of Kansas, Kentucky bluegrass has some potential in lawns and recreational areas. It is best adapted to the Glaciated Region, with its higher rainfall and quality soils. However, those in other parts of eastern Kansas who are fortunate enough to have loam soil should be able to grow Kentucky bluegrass, as well. In Kansas, the best time to plant is September, as the soil will be cooling off and the weeds will be less competitive than in the spring. Before planting, ensure that your lawn seed gets off to a good start by tilling in high-quality organic matter such as compost at a rate of three to six cubic yards per 1,000 square feet of lawn. Broadcast seed at a rate of two to three pounds per 1,000 square feet. To ensure seed germination and seedling survival, water the lawn two or three times a day for the first couple of weeks. After this establishment period, Kentucky bluegrass should require irrigation only weekly and only in hot weather. Mow whenever the grass reaches three inches tall to bring it back down to a height of two inches (never lower than this, or the plants will be damaged and become more susceptible to disease). In the fall, the lawn can be core-aerated every year or two to avoid compaction problems.
Kentucky bluegrass can be invasive in cool, wet climates. This is unlikely to be a serious problem in any part of Kansas.
The pollen of Kentucky is a major contributor to late-spring allergies.
The various varieties of fescue used in lawns may present some identification challenges at first glance. However, bluegrass has thinner blades and produces a fine-textured turf. All types of fescue have wider blades, thus producing a coarser turf.
Parts of a Grass Plant: A Glossary
Definitions for technical terms used in this post.
Grasses of Kansas