In Iowa, there are several types of grass that can be used for a home lawn. They are unique in their own ways, and while for some “grass is grass”, they aren’t always interchangeable. Certain conditions must exist for each of these different grasses to thrive. By the time you finish this blog, you will find that turf selection is really important. We encounter problems on customer lawns with regularity that could easily have been prevented if a different bag of seed would’ve been purchased.
Which Grass Species is Most Suitable for Your Property?
There are thousands and thousands of species of grass across the world, but there are only a few dozen that are suitable for use on lawns, athletic fields, parks, and golf courses. A plant’s ability to withstand regular mowing is the lone trait that separates the “turfgrasses” from the rest of the herd. Those grass types, the select few that we can mow every week without killing it, are segregated into two general groups: warm-season and cool-season. As you likely assumed, we’re in the cool region! To put it simply, cool season grasses are more tolerant of lower temperatures in the spring and fall. Most importantly, they can survive our harsh Midwestern winters and emerge in the spring after a deep hibernation. They can, however, struggle during times of high heat and humidity, which we certainly experience in our area.
Life Cycles for Cool Season Grasses in Iowa
The life-cycles for all cool-season grasses are similar; from mid-March into April, the plant is waking up. As frost leaves the soil and ground temperatures rise, the roots become active and start producing food for the plant to use. With more sunlight and increased temperatures, the plant greens up and starts growing. By mid-April, we consistently have high temperatures in the 60’s, which is when shoot (the visible above-ground part of the plant) growth accelerates. Cool season grasses grow rapidly in May and June, due to a combination of long daylight hours, timely rains, humidity, and high temperatures. When grass is growing rapidly, it can feel like you’re mowing every four or five days, and still struggling to keep up! In July and August, the heat becomes a bit more extreme. This, combined with scarce rain events, causes the plant to slow its root and shoot growth considerably. For some, this is a welcome break from the constant mowing. However, this is a difficult stretch for lawns in our region. Even on lawns that are irrigated regularly, it can be a challenge to keep everything green, healthy and thriving. Usually, lawns slip into dormancy for a few weeks, which is a healthy, normal response. The grass “goes to sleep”, shutting down until environmental conditions improve. Once the worst of the summer weather passes, lawns come out of dormancy on their own. Shorter daylight hours, cooler nighttime temperatures, and a timely rain will alleviate the pain of summer and bring the lawn back to being green. For Cedar Rapids and Iowa City homeowners that feel like their lawn never “woke up”, it may be time to call a professional.
Fall is the best time of year for the health of your lawn. Like spring, we see an increase in root and shoot growth. However, the grass doesn’t grow as fast as it does in the late spring. This is important because it means that more growth and energy is being sent to the roots. This regrowth of root tissue is needed to help the plant recover from the summer, and to help it prepare for winter. Just as in the spring with roots “waking up” before the leaf tissue, the opposite is true in the fall. As temperatures fall, top growth shuts down but roots will continue growing and building energy reserves until the ground freezes. Once the soil freezes, grass goes into winter dormancy, waiting patiently for the next spring to arrive! Our blend of fall lawn treatments ensure that your grass will have all the nutrients it needs to survive the winter and thrive the following spring.
The Seasons of Turf; Warm and Cool
Now that we’ve covered the life cycle of your average cool season grass plant, let’s look at how our country is divided in this turf civil war. The map below shows where “cool” and “warm” climates persist. Just to our south, is a mysterious area known as the “transition zone”. The transition zone is a difficult place to be if you’re a grass plant. Warm season grasses do pretty well here, but winter can be uncomfortable. In years where winter is more harsh than normal, warm season grasses may die off. Cool season grasses are great for 8 or 9 months, but the extreme heat of the summer can be fatal. It is not uncommon for lawns and turf areas in the transition zone to require new seed or sod on a regular basis. Over the past few decades, the transition zone has moved slightly north. This has had an effect on our specific area, which will be discussed in further detail a bit later.
Cool Season Grass Species in Iowa
The most widely used grass on lawns throughout Iowa, especially Cedar Rapids and Iowa City, is Kentucky bluegrass. When weighing all the pros and cons of different grass types, it is the ideal grass type for use on lawns in Iowa. Kentucky bluegrass has a leaf texture that is much softer than most other cool-season grasses. Walking barefoot across the lawn isn’t possible or comfortable on many grass types. However, it is one of the perks of having a thick, healthy bluegrass lawn! It has a wide range of colors; from lighter “John Deere” green to the deep, blue/green shades found in many of the popular newer varieties. Kentucky bluegrass spreads through underground roots called rhizomes. This ability to spread can create a thick, dense carpet of turf once a stand of bluegrass has established. These roots also give bluegrass the ability to “fill in” areas where turf is thin/sparse, recover from damage more readily, and form a sod that can be cut and transported. Kentucky bluegrass is the best-suited grass type for use in sod production.
Kentucky bluegrass does well in full sun environments. It is the premier turf for use on athletic fields, where shade is minimized. On newly constructed homes, you will typically find that at least part of the lawn has been sodded. With minimal shade present in new developments, it is the best turf type to use. However, there IS some benefit to having partial or intermittent shade on a bluegrass lawn that is not irrigated. In the hottest stretch of summer, having a few hours of shade is extremely beneficial. It helps cool the soil and reduces the amount of water used by the plant. Knowing whether or not you have too much shade can be tricky, especially when it’s something that can be subjective, and it changes over the course of decades as trees grow larger. We frequently see lawns where the difference between “Needs shade” to “Whoa! Too much shade!” can be 15 paces. My general rule of thumb for bluegrass lawns; if an area will receive shade from 2 or more trees, it will struggle. Later, I will discuss seed blends and how they are used to cover all bases and take the subjectivity out of decision making.
There are a few drawbacks to Kentucky bluegrass, and because of those, the way we care for Kentucky bluegrass must account for them. It is not very tolerant to high-traffic areas. Large dogs can present challenges if they are confined to specific areas, and constant walking traffic can slowly beat an area down. If these issues are present, moving those traffic patterns will result in recovery, and yearly aeration will alleviate soil compaction. As mentioned earlier, bluegrass does recover rather quickly from any type of stress. Also, Kentucky bluegrass requires more water than other grass types. additional irrigation will likely be needed in stretches of summer when rainfall is sparse, to keep the plant green and healthy. However, this can be a lot of work and rather pricey. Letting Kentucky bluegrass slip into dormancy is normal and completely fine, and as we’ve discussed, the plant will recover when weather conditions improve. Having a bit of shade helps bluegrass weather the hot/dry stretches of summer, and we constantly stress the importance of mowing your lawn a bit longer in the summer for this very reason. By keeping more leaf tissue on the plant, less water is lost. Proper mowing height can make a huge difference in keeping your plant healthy and vibrant!
Kentucky bluegrass, because of its rapid growth and underground stems, can produce a lot of thatch. Yearly aerating or a spring rake helps keep thatch at healthy levels. Spring raking is done early in the spring and is just like if you were raking leaves in the fall. The purpose is to remove dormant grass and thatch with the goal of increasing air flow to the soil, breaking up the barrier of dead material that soaks up water and nutrients, and giving the lawn a head start to greening up in the spring. This valuable service is offered by UltraLawn and is done with mechanical attachments to our mowing equipment, which helps move more material with greater efficiency. Please contact us if you are interested in an aeration or spring rake, and speak with our experts about what you can do to improve the health of your Kentucky bluegrass lawn.
Another grass type that is frequently used in Iowa is Perennial ryegrass. However, it is not used in the same manner as Kentucky bluegrass. Ryegrass is added to seed blends because of its unique positive traits, but it is not common for a lawn to be predominantly ryegrass. There are some special instances where pure stands of perennial ryegrass are found.
The hallowed tennis courts at the All-England Tennis Club are perennial ryegrass, because it does well in high-traffic areas, can thrive at lower mowing heights (the courts of Wimbledon are kept at roughly 0.4”), and persists in the cloudy, dreary weather that is common in Great Britain.
On golf courses in the south, ryegrass is used to overseed where warm-season turf goes dormant. Ryegrass germinates from seed very quickly; usually in 3-5 days. That quick germination time is very appealing, as it means less time to deal with a “brown” golf course. Winters, even in areas that we think of as being warm and pleasant, can still offer some very cool stretches. Perennial ryegrass has very good cold tolerance, making it an excellent choice for winter overseeding.
Ryegrass is also used for overseeding in our region, but predominantly on high-traffic athletic fields. Over the course of a season, soccer and football fields wear out considerably. There’s a high concentration of aggressive foot traffic that turf cannot withstand after weeks and months. Ryegrass is used extensively throughout the season for overseeding these thin areas, because of the quick germination and it has a higher rate of germination at colder temperatures. This is imperative when talking about soccer and football, which are played in the fall as temperatures drop. However, there is a potential drawback to using ryegrass extensively for overseeding. Ryegrass has a shiny, slippery leaf surface. Over time, the concentration of ryegrass in these high-traffic areas (between the 20-yard lines for football fields) becomes so thick that the playing surface potentially becomes slippery. Years ago, legendary Iowa coach Hayden Fry was accused of using ryegrass as a tactic for slowing down faster teams that had to play at Kinnick Stadium.
Perennial ryegrass is used extensively in seed blends with Kentucky bluegrass. They have a similar appearance and texture, making it difficult at times to tell the difference between the two. As mentioned several times in this blog already, ryegrass germinates from seed very quickly. This is perfect for covering up one of the biggest drawbacks to Kentucky bluegrass; slow germination times! Bluegrass can take 14-21 days to germinate, which can be extremely frustrating for anyone trying to start it from seed. Ryegrass will germinate within the first week (if it’s getting enough water!) and will provide cover and erosion protection while we wait for bluegrass to come in. Once the bluegrass does take hold and fill in, the ryegrass blends nicely to from a consistent stand.
There are some traits of perennial ryegrass that should be kept in mind. It is not a very deep-rooted grass, so drought tolerance isn’t great. It will need to be watered to avoid dormancy just like Kentucky bluegrass. Perennial ryegrass is considered a “bunch-type” grass, meaning that it does not spread through horizontal stems or roots like Kentucky bluegrass. Where each seed germinates, that individual plant grows and matures to eventually form a clump of grass. At that point, the plant has reached maturity and won’t get any larger. If there are thin areas that need filled in, it will have to be done with additional seeding.
The first two grass types we’ve discussed are well-suited for Iowa lawns receiving a great deal of sunlight. The next grass type we’ll discuss is our best weapon for a situation where shade is an issue. Before we go any further, it must be noted that no grass will survive in an area that is completely shaded. Sunlight is one of the ingredients needed for plants to create food. Even though there are some plants that do well in shady landscape settings, the requirements for grass are a bit different. “Full shade” does not mean “no sunlight”. No matter the plant, it still requires at least a few hours of direct or filtered sunlight. Landscaping plants with large leaves have a great deal of chlorophyll to create carbohydrates and make up for the lack of sunlight. Grasses don’t have the extensive leaf surface to do that. Add in the fact that regular mowing puts pressure on turf to constantly grow and replenish, and it makes shady situations even more difficult.
Fine-leaf fescues refer to a family of grass species that all have a few traits in common. Their leaf blades are extremely thin, similar to the needles from a pine tree. Most of them grow in clumps, which limits just how thick it will get unless thin areas are overseeded. Creeping red fescue DOES spread through rhizomes, making it an outlier from the other fine fescues. This spread isn’t as aggressive as Kentucky bluegrass, so fine fescues won’t develop into a thick sod like bluegrass. Although there are several species of fine-leaf fescues, they are almost always blended. They have slightly different colorations, but it isn’t noticeable when they are mixed together. A pure stand of fine fescue can make a very nice lawn surface. It doesn’t grow very fast, meaning less time will be spent mowing. It requires less water AND less fertilizer than other turf types, and even prefers dry soil. A common use for fine fescue has been to establish low maintenance areas in parks, around bodies of water, and on golf courses. These natural habitats are great for wildlife, erosion control, and aesthetic value. Fine fescue can be considered a “low-input” turf since it requires low amounts of fertilizer and water.
Part of what makes fine-leaf fescues require less, is that they are best suited for shade. In those shady environments, plants grow slower. That slow growth means less nutrients and water are required to create food for the plant. Going further, less mowing results in less fuel use and carbon emissions. Fescues are native to Europe, and are often seen on the rolling hills of Great Britain. The cool air, filtered sunlight, and sandy soils that are present in that environment are perfect for fescues. While soils in our area tend to be clay-based, there are areas where sandy soils are prevalent. Those soils, combined with a decent amount of shade, creates a micro-climate that is perfect for fine fescue!
While the name is similar, and they’re in the same family, there aren’t many similarities between tall fescue and fine-leaf fescues. Tall fescue is usually seen as a weed, or an undesirable grass in the lawn. It has a very wide leaf blade and a stiff texture. It grows in a large clump that is unsightly and can create humps in the lawn that disrupts its smoothness. Tall fescue grows very quickly, and you will notice this a few days after mowing. It will stick out above the rest of the lawn, and is rather unsightly in the lawn. We hear many complaints about it from our customers! The picture below shows a Kentucky bluegrass lawn with some clumps of tall fescue.
It’s hard to pinpoint exactly where this tall fescue comes from, especially when it pops through a lawn that was sodded with bluegrass. Tall fescue is frequently found in pastures, waterways, terraces, and other areas in agriculture where grasses are present. As grasses grow and develop seeds, those seeds fall to the ground and never germinate. Over time, those seeds bury themselves in the soil in what is called the “seed bank”. When old farmland is developed into residential lots, there is a lot of soil moved around. Through that process, old, long-buried seeds are brought back up to the surface. Seeds can sit in dormancy for decades and decades, but when given enough water and sunlight, will germinate. That is one explanation for how tall fescue appears in lawns, especially those that are newly sodded with lush, thick bluegrass. Another possibility is that seeds are moved by wildlife, especially birds. Tall fescue is sometimes found in seed blends. If a homeowner isn’t careful, they might end up putting tall fescue seed in their lawn without realizing it.
Tall fescue is immensely frustrating because it can’t be controlled easily. There are no selective herbicides that will eliminate tall fescue without damaging the turf around it. Since it is also a cool-season turfgrass, it’s nearly impossible to develop products to eliminate it from other cool-season grasses. The only chemical treatment that can work on tall fescue is something like Round-Up. The danger in using a non-selective herbicide is damaging plants that you want to keep. In situations where the tall fescue is growing in a tight clump, it will be easy to selectively treat only that area. It becomes more difficult if the tall fescue is growing amongst the lawn. Since it does grow faster, there is a technique that can be used where a brush is used to “paint” the longer fescue leaves with a 2% Round-Up solution. This is not for the faint of heart, as this technique is difficult to execute well.
If you are successful at using Round-Up (glyphosate), you will then be left with spots of dead turf throughout the lawn. Depending on your patience level, you can leave them alone and they will decompose naturally as the lawn around it fills in. It will only fill in on its own if you have Kentucky bluegrass, as that is the only turf type that spreads. This may take some time, especially if the tall fescue clumps were large. If they were, you may need to dig them out and replace those holes with fresh topsoil. From there, you can seed those spots, sod them with small pieces, or let them fill in. Seeding into an established lawn can be tricky, especially a lawn that is receiving lawn applications or isn’t irrigated. Spring pre-emergent products for crabgrass interfere with new seeding, and we see this mistake a lot. It’s understandable that a homeowner wants to fill in thin areas with some supplemental seeding, but if they also apply crabgrass preventer, then all their work is for naught. The watering needs for new seed or sod also pose a challenge when it’s done in an existing lawn. Mature turf doesn’t require nearly as much water as new seed does, and overwatering grass can be detrimental to the plant’s health. Spot-watering would be necessary for caring for these areas, as setting up a sprinkler or operating overhead irrigation will result in too much water where it doesn’t need to go.
Despite all the negative things we’ve just said about tall fescue and how to get rid of it, there have been great strides made in recent years in creating varieties of tall fescue that are much more desirable. These newer cultivars are referred to as “turf-type” tall fescues (or TTTF). These have grown in popularity on athletic fields because they hold up well to traffic, like the older varieties of tall fescue before them. They’re also showing themselves to be a great option for the lawn as well. Drought tolerance isn’t quite as impressive with TTTF, but still better than bluegrass or ryegrass. There are still some issues being worked out with TTTF’s, but there is potential for them becoming a desirable grass type for lawns!
Grass Seed Blends
Several times in this blog, we’ve alluded to “seed blends”. When new lawns are seeded, or seed is sold in stores, it is rarely a single grass type. Each grass type we’ve covered has specific advantages and disadvantages, but thrives in fairly specific conditions. Most lawns have several different growing environments; shady spots between houses or where it faces north, a low-lying area that doesn’t drain well, a south-facing slope that drains TOO well…it’s rare that a single grass type is ideal for every square inch of a lawn. By putting a few grass types together, it covers more of these “micro-climates”.
Lawn seed is generally blended, marketed, and packaged into several groups:
–Full Sun- This blend is going to be predominantly Kentucky bluegrass and perennial ryegrass. The exact percentages may vary, and there will likely be at least two cultivars of each grass type. Ryegrass will germinate quickly and provide cover until the bluegrass germinates and matures. There is a bit of a visual difference between the two grasses, but that will be harder to discern as the lawn fills in. Some lower maintenance blends will also have tall fescue for its drought and traffic tolerance.
–Full Shade- Grass seed meant for success in the shade will lean heavily on fescues. Both the fine-leaf fescues and tall fescue perform well in shady environments. However, they are so different aesthetically that one must be thorough in looking at the label for these blends. If both tall and fine-leaf fescues are used, the result will have an inconsistent appearance. Shady environments are difficult for turf, but it’s important to choose something that will give the best appearance possible.
-Sun & Shade Mix- These products are usually a “catch-all” for home lawns where all sorts of growing conditions are present. These will have a few varieties each of Kentucky bluegrass, perennial ryegrass, and fine-leaf fescues. The general philosophy is that over time, certain grasses will adapt better to a specific area and take over. Bluegrass and ryegrass will proliferate where it’s sunnier, the fine fescues will do better than the others in the shade. One problem is that this approach isn’t very focused, and the consumer will end up planting seed in areas that has no chance of surviving. If 30% of the seeds are fine fescue, that means there are a lot of seeds being planted in the shade for nothing. And, with such a small amount having a chance, then how much grass will actually grow in these areas? Bluegrass will spread on its own and fill in, but fine fescue does not have that capability. If the fescue isn’t very thick, it will require additional seeding at some point in the future.
-Contractor’s Blend- This kind of lawn mix has two goals: Germinate fast and be cheap! The final step after many types of construction projects is to lay seed down and move on to the next job. We’ve found these mixes to be predominantly ryegrass (both annual and perennial), and tall fescue. Unless it is an improved turf-type variety, we wouldn’t recommend seeding with tall fescue. The problematic part is the annual ryegrass being used. As the name suggests, an annual plant lives for one year, then dies. Annual ryegrass is best suited as a cover crop in agricultural settings. It does have a limited purpose for home lawns. If fast germination is needed to keep the ground in place, with the intention of seeding with a more permanent solution the following year, then annual ryegrass does make sense. This scenario is limited to a situation where seeding must be done late in the fall and fast germination is necessary.
Selecting the right type of turf is extremely important to having the best lawn possible. The professional staff at UltraLawn will be able to evaluate your property and come up with a plan to make your lawn as healthy as possible. We have access to professional-grade products that will go a long way in making sure your project is a successful one! Give UltraLawn a call today and have the experts on your side!