Cool Season Grasses: Definition, Types and Uses

With a fibrous root system, cool-season grasses include some of the most popular species, such as tall fescue, Kentucky bluegrass, perennial ryegrass, chewings fescue, and creeping red fescue, among others. 

Typically, cool-season grasses grow in regions like the Pacific Northwest, the Upper Midwest, New England, and Northern California, along with other upper two-thirds of the United States.

Cool-season grasses come under a category providing assistance for overseeding troubled spots in your lawns, forming new lawns, and areas for livestock forage.

1. Kentucky Bluegrass

Kentucky bluegrass, also known as Poa pratensis, is native to Europe, North Asia and the mountains of Algeria and Morocco. And in the western states, this cool-season lawn grass is grown with irrigation. It grows 18 to 24 inches tall and can be identified by its boat-shaped leaf tip. While Kentucky bluegrass grows most vigorously, the appearance of new leaves takes around ten days in the spring to 22 days in the summer and fall.

During the establishment stage, Kentucky bluegrass requires at least 5 to 6 pounds of nitrogen in the first year and 2 to 3 pounds in the subsequent years for adequate growth and maintenance. This cool-season grass thrives in full sun, but some varieties flourish in shaded areas. 

Of all the common cool-season U.S. lawn grasses, Kentucky bluegrass is the only one with excellent winter hardiness. Even though the Kentucky bluegrass grows and repairs by itself, it still needs proper care, a high level of maintenance, and favorable growing conditions. Watering, fertilizing, aerating, pulling out weeds, and mowing correctly with a strict schedule can land you a dense, lush, durable lawn that exceeds your expectations. Remember that the optimal time to germinate and propagate Kentucky bluegrass is during early fall.

2. Perennial Ryegrass

Perennial ryegrass, commonly known as Lolium perenne, is identified for its speedy germination trait. While most homeowners might not take it as a serious attribute compared to Kentucky bluegrass, which makes an ideal lawn or fescues that are preferred due to low maintenance, perennial ryegrass is much more than a nurse grass. 

With the feature of withstanding light shade, perennial ryegrass flourishes in the regions with moderate summers and cool winters. Although this cool-season grass is most widely used as permanent lawn grasses, some of its varieties struggle to thrive in shady areas. Perennial ryegrass is identified by its coarse texture and produces bunch-forming grass, unlike the Kentucky bluegrass that aggressively spreads through underground stems called rhizomes.

Perennial ryegrass is grown for its ability to germinate quickly and the function of providing shade and protection to other grass types which might take up to three weeks to establish, such as Kentucky bluegrass. While perennial ryegrass does well in mild coastal regions, to acquire perfect re-establishing greens, you should water them two to four times per day until the first germination. With the establishment, you can lower the irrigation frequency. In addition, this cool-season grass prefers soil with a pH of 5.5 to 7.5. 

Regarding care and maintenance, you must consider mowing the perennial ryegrass to 1 ½ – 2 ½ inches for dense growth. Fertilizing nitrogen per year during its active growth period will also render an excellent pastoral or turf choice of grass for your cooler region.

3. Fine Fescues

Fescue (genus Festuca) comes from the Poaceae grass family and is available in two distinct species – tall fescue and fine fescue. Fine fescues are identified by their fine and narrow leaf blades and are mostly in demand due to their low-maintenance characteristic since they still look attractive when left un-mowed. 

Eden recommends using the soil with a pH of 5.0 to 6.5 for fine fescues to flourish, but you must avoid planting it on heavily trafficked areas like an athletic field. Being a shade and cold tolerance grass type, this species is mainly used to establish a thick and lush lawn for home. 

Care and maintenance are a critical part of the upkeep of your lawn. In case of fine fescues, homeowners don’t have to think twice before finalizing this grass type if they are looking for low-maintenance turfgrass. 

Fine fescues are drought tolerant and also have low fertilizing needs. They come with a high tolerance for low mowing, but when it comes to irrigation, they require consistent moisture during the establishment stage. You must follow an irrigation and fertilizing schedule to flourish on your lawn and prevent them from going dormant.

4. Tall Fescue

Festuca arundinacea or tall fescue is mostly used as forage grass throughout Europe. It is mostly preferred due to its heat, cold, drought and shade tolerance. They are also the number one choice for homeowners who wish to enhance the resilience and durability of their lawns. 

Tall fescue is also available in various cultivars with a bunch forming growth habit. One can easily identify the tall fescue with its wide-dark green color leaf blades, which are very coarse to touch. Even though this type of cool-season grass maintains itself in the winter weather, it still requires a moist environment, soil with a pH range between 5.5 and 7.5, and a 3-1-2 ratio formula of the fertilizer. 

Known for its tolerance for disease and pests, tall fescue lets the gardener down because of its limited capacity for self-repair. At the same time, the care and maintenance of tall fescue involves full or partial sun exposure, one ¾ inch of water, and soil pH range between 5.5 – 6.5 with good drainage and high fertility. 

5. Bentgrass

Emerging from the stolons, bentgrass is a perennial creeping grass that produces dense, bluish-green foliage. Bentgrass typically thrives and grows rapidly in cool, humid environments. When propagating, bentgrass initially has light-colored patches but eventually turns wilted and brown during the summer.

You can easily identify bentgrass through its horizontal growth pattern and shallow root system. Looking at its appearance and growth pattern, this grass type does not seem to complement a home lawn. However, bentgrass is mostly used as pasture for grazing animals. But, it does not imply that people do not wish to grow this grass in their yard. Due to its dense, bluish-green foliage and ability to withstand high foot traffic, bentgrass is also grown as lawns. 

Since bentgrass is a useful species for cool zone lawns, getting familiar with the care instructions is also essential to maintain it. Due to its low mowing height requirements, one must schedule frequent mowing for this grass type. Also, high amounts of fertilizer and correct irrigation are required to keep bentgrass.  

6. Rough Bluegrass

Rough bluegrass or rough talk isn’t as adaptable as the other cool-season grass species due to its intolerance for drought, heat, and traffic. While this cool-season grass species thrives in cool, moist conditions, it is often confused with Kentucky bluegrass. However, you can distinguish between them by examining their root structure. Kentucky bluegrass comes with rhizomes that grow below the ground, and rough bluegrass includes stolons above ground. 

When it comes to the uses of this grass type, one might think it has none due to its patchy appearance and lack of complementing the lawn with another species of grass. However, it is sometimes used in combination with ryegrass (perennial/annual) for winter overseeding of golf courses. Rough bluegrass can also withstand a little shade, given that sufficient moisture is present. 

But, rough bluegrass comes with its fair share of pros and cons. While it has a high tolerance for low temperature, it is susceptible to most turfgrass insects and diseases. 

A moderate to high maintenance schedule works with this grass type, given its low tolerance for foot traffic, heat, and drought. But with rich and fertile soil, frequent fertilization, and right irrigation, you can acquire flourishing rough bluegrass. 

7. Creeping Fescue

Red fescue or creeping fescue (Festuca Rubra) in your lawn will render fine grass blades with a medium to dark green color. No matter your soil type, creeping fescue can grow quickly and well, even in sandy soil, while covering a lot of areas, which is why it is suitable for tough home lawns, golf courses, and recreation fields.

Red fescue can tolerate cold to an extent, but it is not as cold tolerant as the other species of cold-season grasses, such as Kentucky bluegrass.

Ensure that your lawn is fully irrigated. In summers, you can water your red fescues once or twice a week. However, during the dormant season, consider watering not more than twice a month. Fertilize well during the establishing stage and refrain from fertilizing red fescues’ in dormant days. 

In the case of mowing, keep the glass blades between 1 to 3 inches. While creeping red fescue grass is susceptible to white grubs and billbugs, you can prevent these pests and diseases with a suitable herbicide.

8. Annual Ryegrass

Annual ryegrass, also known as Italian ryegrass, is known for its erosion control and winter overseeding of warm-season lawns. This cool-season lawn grass also includes rapid germination and establishment. It also resists disease while tolerating foot traffic. Coming to its tolerance for cold, annual ryegrass struggles in extreme cold and heat weather, unlike the other cool-season grass types. It flourishes in moderate northern summers and moderate southern winters. 

Keeping the mowing height of 2 to 3 inches, following timely irrigation of up to 1 ¼ inches and the right fertilizing schedule are some of the care instructions to maintain the winter color. 

What are the Maintenance Needs of Cool-season Grasses?

Mowing, fertilizing, and irrigating seem to be the three most essential steps that you must take care of to maintain your turfgrass or lawn. With cool-season grasses also, these are the same maintenance needs. However, the level of maintenance varies depending on the type of cool-season grass you wish to plant and take care of. 

• Mowing – 2.5 – 3.5 inches is the ideal mowing height that most landscapers recommend. However, the Eden experts suggest never to remove more than 1/3 of the grass height. And if your cool-season grass blades are too tall, then you should mow them once at a high setting and again at a lower setting a few days later. Again the various cool-season grass species have distinct requirements. For instance, Kentucky bluegrass and tall fescue need mowing once or twice a week. 
• Irrigation – Depending on the weather conditions, the watering level can range from moderate to high. However, the drought tolerance also plays a part in this stage. While rough bluegrass has no tolerance for drought, Kentucky bluegrass can survive in extreme drought conditions. However, Eden professionals also recommend watering between 4 am to 12 noon to prevent any signs of fungus pressure on your lawn since the turf dries up during the afternoon. 
• Fertilization – Fertilizing during spring after the winter dormancy assists your turfgrass or cool-season grass revive its lush, green appearance. While established turfgrass requires mainly nitrogen, you can apply crabgrass pre-emergent along with the fertilizer if crabgrass was a problem last year. Eden also recommends using a fertilizer spreader to help apply the product evenly and refrain from spreading too much fertilizer. 

Overseeding, grub control, and leaf removal are some areas that you must take care of to maintain your lawn effectively and effortlessly. 

To conclude, the types of cool-season grasses are ‒ Tall fescue, Kentucky bluegrass, perennial ryegrass, and chewings fescue, and creeping red fescue, among others. Cool-season grasses can be used for overseeding troubled spots in your lawns, forming new lawns, and areas for livestock forage.

Contact Eden’s professionals to help you establish various cool-season grasses in your lawn or yard.